National Climate Observing System Klima-Beobachtungssystem

Klima_S0000_Umschlag.indd 6

ABBREVIATIONSABKÜRZUNGEN Global ClimateObservingSystem – GCOSSwitzerland Climate ObservingSystem National Global ClimateObservingSystem–GCOSSchweiz Klima-Beobachtungssystem Nationales 12.3.2008 16:07:05 Uhr Abbreviations

AERONET Aerosol Robotic Network ICSU International Council for Science AGNES Automated GPS Network in Switzerland IDNDR International Decade for Natural Disaster Reduction AMDAR Aircraft Meteorological Data Reporting IGRA Integrated Global Radiosonde Archive ANETZ Automated Monitoring Network IGRAC International Groundwater Resources Assessment Centre AOD Aerosol Optical Depth IMIS Intercantonal Measurement and Information System ASRB Alpine Surface Radiation Budget IPCC Intergovernmental Panel on Climate Change (A)ATSR (Advanced) Along Track Scanning Radiometer IPG International Phenological Gardens AVHRR Advanced Very High Resolution Radiometer ISDR International Strategy for Disaster Reduction BSRN Baseline Surface Radiation Network IUGG International Union of Geodesy and Geophysics CHARM Swiss Atmospheric Radiation Monitoring JMA Japanese Meteorological Agency CIMO Commission for Instruments and Methods of Observation JRC Joint Research Centre, Ispra CM-SAF Satellite Application Facility for Climate Monitoring KLIMA Conventional Monitoring Network CNRS Centre National de la Recherche Scientifique LKO Licht-Klimatisches Observatorium Arosa COP Conference of the Parties LULUCF Land Use, Land-Use Change and Forestry CORINE Coordinated Information on the Environment LWF Longterm Forest Ecosystem Research COST European Cooperation in the field of Scientific and Technical Research MERIS Medium Resolution Imaging Spectrometer Instrument CWINDE European Windprofiler Network MeteoSwiss Federal Office of Meteorology and Climatology DDPS Federal Department of Defense, Civil Protection and Sport MISR Multiangle Imaging SpectroRadiometer DETEC Federal Department of the Environment, Transport, Energy and MODIS Moderate Resolution Imaging Spectroradiometer Communications MVIRI Meteosat Visible and Infrared Imager DLR German Aerospace Center NABEL National Air Pollution Monitoring Network DWD Deutscher Wetterdienst NADUF National River Monitoring and Survey Programme EAN European Aeroallergen Network NAPOL National Pollen Monitoring Network EARLINET European Aerosol Research Lidar Network NAQUA National Groundwater Observation Programme Eawag Swiss Federal Institude of Aquatic Science and Technology NASA National Aeronautics and Space Administration ECC European Cloud Climatology NBCN National Basic Climatological Network ECMWF European Center for Medium-Range Weather Forecasts NCCR National Center of Competence in Research EEA European Environment Agency NCDC National Climatic Data Center EKK Cryospheric Commission of SCNAT NDACC Network for the Detection of Atmospheric Composition Change EMEP European Monitoring and Evaluation Programme NILU Norwegian Institute for Air Research Empa Swiss Federal Laboratory for Materials Testing and Research NIME Precipitation Monitoring Network ENET Supplementary Network NOAA National Oceanic and Atmospheric Administration EPFL Swiss Federal Institute of Technology Lausanne NRP National Research Programme EPN European Phenology Network NSIDC National Snow and Ice Data Center ERS European Remote Sensing Satellite OBS Visual Observations Network ESA European Space Agency OcCC Advisory Body on Climate Change ETH Swiss Federal Institute of Technology Zurich (ETHZ) OECD Organisation for Economic Cooperation and Development EUMETSAT European Organisation for the Exploitation of Meteorological Satellites OMI Ozone Monitoring Instrument EUVC European Ultraviolet Radiometer Calibration Center OPERA Operational Program for the Exchange of weather RAdar information FAGS Federation of Astronomical and Geophysical Data Analysis Services PERMOS Permafrost Monitoring Switzerland FAO Food and Agriculture Organization of the United Nations PMOD Physical Meteorological Observatory Davos FOAG Federal Office for Agriculture PSI Paul Scherrer Institute FOEN Federal Office for the Environment QA/SAC Quality Assurance/Scientific Activity Centre FoG Fluctuations of Glaciers RBCN Regional Basic Climatological Network FOPH Federal Office of Public Health SCNAT Swiss Academy of Sciences FSO Federal Statistical Office SEVIRI Spinning Enhanced Visible and InfraRed Imager GAW Global Atmosphere Watch SGI Swiss Glacier Inventory GCOS Global Climate Observing System SLF Swiss Federal Institute for Snow and Avalanche Research GEBA Global Energy Balance Archive SOGE System for Observation of Halogenated Greenhouse Gases in Europe GEWEX Global Energy and Water Experiment SR Systematische Sammlung des Bundesrechts GFMC Global Fire Monitoring Center swisstopo Federal Office of Topography GLIMS Global Land Ice Measurements from Space UNECE United Nations Economic Commission for Europe GLORIA Global Observation Research Initiative in Alpine Environments UNEP United Nations Environment Programme GMBB Glacier Mass Balance Bulletin UNESCO United Nations Educational, Scientific and Cultural Organization GMES Global Monitoring for Environment and Security UNFCCC United Nations Framework Convention on Climate Change GNIP Global Network of Isotopes in Precipitation VAW Laboratory of Hydraulics, Hydrology and Glaciology GOME Global Ozone Monitoring Experiment WCC World Calibration Center GPS Global Positioning System WCP World Climate Programme GRDC Global Runoff Data Centre WCRP World Climate Research Programme GRUAN GCOS Reference Upper Air Network WDCA World Data Centre for Aerosols GSN GCOS Surface Network WDCGG World Data Centre for Greenhouse Gases GTN Global Terrestrial Network (-G: Glaciers; -H: Hydrology; -P: Permafrost) WGI World Glacier Inventory GTOS Global Terrestrial Observing System WGMS World Glacier Monitoring Service GUAN GCOS Upper Air Network WMO World Meteorological Organization HFSJ High Altitude Research Station Jungfraujoch WORCC World Optical depth Research and Calibration Center HUG Hydrological Study Areas WOUDC World Ozone and Ultraviolet Radiation Data Center IAC Institute for Atmospheric and Climate Science WRC World Radiation Center IACS International Association of Cryospheric Sciences WRC-IRS World Radiation Center, Infrared Radiometry Section IAEA International Atomic Energy Agency WRC-SRS World Radiation Center, Solar Radiometry Section IAP Institute of Applied Physics WRMC World Radiation Monitoring Center ICP International Co-operative Programme WSL Swiss Federal Institute for Forest, Snow and Landscape Research

Klima_S0000_Umschlag.indd 3 6.3.2008 14:38:45 Uhr National Climate Observing System Global Climate Observing System – GCOS Switzerland

Klima_S01_I_II_Impressum_Vorwort.indd 90 5.3.2008 8:29:12 Uhr Imprint

Editor Swiss GCOS Office Gabriela Seiz, Nando Foppa

Federal Office of Meteorology and Climatology MeteoSwiss Krähbühlstrasse 58 CH-8044 Zurich

http://www.gcos.ch

Citation Seiz, G., Foppa, N., 2007. National Climate Observing System (GCOS Switzerland). Publication of MeteoSwiss and ProClim, 92 p.

Layout BBG Werbung AG, Thalwil

Printed at Schellenberg Druck AG, Pfäffikon ZH

Translation Jeff Acheson

Klima_S01_I_II_Impressum_Vorwort.indd 91 5.3.2008 8:29:12 Uhr Foreword Scientific data collection requires continuity. Trends and new developments cannot be detected with an isolated snapshot. Equally, sound conclusions as to how our climate is changing can only be reached on the basis of regular, standardized observations of different climate variables. As is strikingly demonstrated by the recently published Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the key findings and conclusions on the state of the climate are dependent on a correct assessment of the chronology of changes. If we were

not able to place today’s elevated atmospheric CO2 concentrations – or the dramatic retreat of Alpine glaciers – within the detailed historical context of the past 50 years’ developments, we would be unaware of the true interactions within this complex system.

In a country where lives are shaped by changes in the environment, there is a long tradition of systematic observation. Accordingly, Switzerland has numerous long-term data series, which are now part of the fundamental information on the climate system used by researchers and the authorities alike. The expertise acquired through these activities makes Switzerland an important partner in international climate observation programmes.

This report makes available for the first time a comprehensive inventory of the climate variables that have been observed in Switzerland for many years. It thus provides a starting point for the formulation of a financial and legislative strategy to secure the future of the national climate observing system.

Bern, October 2007

Thomas Stocker Kathy Riklin ProClim President OcCC President

Klima_S01_I_II_Impressum_Vorwort.indd 1 5.3.2008 8:29:12 Uhr Klima_S02_03_Zusammenfassung.indd 2 5.3.2008 8:41:00 Uhr Summary

Switzerland has a long tradition of climate La Suisse a une longue tradition en matière observation. Temperature and precipitation d’observation du climat. Des séries de plus de series of more than 150 years, the world’s 150 ans de mesures de la température et des longest total ozone series, glacier measure- précipitations, la plus longue série de l’ozone ments dating back to the end of the 19th total dans le monde, des mesures glaciologiques century and the 100-year anniversary of the depuis la fin du 19e siècle et cent ans d’activité Physical Meteorological Observatory Davos are de l’Observatoire physico-météorologique de only a few of the highlights of Switzerland’s Davos ne sont que quelques-uns des grands contribution to global and regional climate jalons de la contribution suisse au monitorage monitoring. mondial et régional du climat.

The value of Swiss climate measurement series La grande valeur des séries suisses de mesure lies in their long-term continuity, systematic climatiques tient à leur continuité, à des acquisition and remarkable quality. It should be relevés systématiques et à une remarquable borne in mind that if measurement series are qualité. L’interruption de telles séries est donc interrupted, the loss of continuity is irrevocable. irrévocable. Par ce rapport, le Swiss GCOS This report, prepared by the Swiss GCOS Office à l’Office fédéral de météorologie et Office at the Federal Office of Meteorology climato-logie MétéoSuisse donne pour la pre- and Climatology MeteoSwiss, provides, for mière fois un large aperçu des plus précieuses the first time, a comprehensive overview of des longues séries de variables climatiques the most valuable long series of essential essentielles. Cette synthèse examine pour climate variables. For each variable, the report chacune d’elles si des bases légales, des com- identifies any gaps regarding the legal basis, pétences ou des ressources financières font definition of responsibilities or availability of défaut pour assurer leur continuation. financial resources for the continuation of observations. Des dispositions sont requises notamment pour l’observation de la cryosphère (glaciers, There is a clear need for action with regard to pergélisol, neige): il n’existe aucune base the cryosphere observations (glaciers, perma- lé-gale à ce sujet, ainsi le financement de ces frost, snow): there is no legal basis and con- séries de mesure n’est-il pas assuré à long sequently, the funding of measurement series terme. Un besoin de financement existe aussi

is not assured in the long term. In addition, pour la série de mesure du CO2 au Jungfrau-

funding is required for the CO2 measurement joch, pour des séries d’observation des lacs series on the Jungfraujoch, for observations et de la phénologie, ainsi que pour trois cen- of lakes and phenology, and for three inter- tres internationaux de données en Suisse. Les national data centres in Switzerland. The longues séries de mesure du système natio- presented long-term measurement series of nal d’observation du climat (GCOS Suisse) the National Climate Observing System (GCOS ici présentées, sont primordiales pour la Switzerland) are crucial to our understanding compréhension du changement climatique et of climate change, and for the planning and pour la planification et réalisation de mesures implementation of appropriate measures. adéquates.

Klima_S02_03_Zusammenfassung.indd 3 12.3.2008 15:58:16 Uhr Contents

1 Introduction 6 – 11 2 Atmospheric 3 Terrestrial observations 12 – 39 observations 40 – 67

Background 6 Surface Hydrosphere Motivation 10 Procedure 11 2.1 Air temperature 12 3.1 River discharge 40 Structure 11 2.2 Precipitation 14 3.2 Lakes 42 2.3 Air pressure 16 3.3 Groundwater 44 2.4 Sunshine duration 18 3.4 Water use 46 2.5 Radiation 20 3.5 Isotopes 48

Upper air Cryosphere

2.6 Clouds 22 3.6 Snow cover 50 2.7 Water vapour 24 3.7 Glaciers 54 3.8 Permafrost 58

Composition Biosphere

2.8 Ozone 26 3.9 Land use 60 2.9 Carbon dioxide 30 3.10 Forest ecosystem 62 2.10 Greenhouse gases 32 3.11 Forest fires 64 2.11 Air pollutants 34 3.12 Phenology 66 2.12 Aerosols 36 2.13 Pollen 38

Klima_S04_05_Inhaltsverzeichnis.indd 4 5.3.2008 9:01:04 Uhr 4 International 5 Observations outside 6 Conclusions and centres 68 – 75 Switzerland 76 – 79 outlook 80 – 92

4.1 GEBA 68 Ozone (Kenya) 77 Conclusions 80 4.2 BSRN 70 Trace gases (Kenya, Indonesia, Algeria) 78 Outlook 83 4.3 WGMS 72 Glaciers 79 4.4 Other centres 74 Appendix Authors and reviewers 84 References 86 Picture credits 90 Abbreviations 92

Klima_S04_05_Inhaltsverzeichnis.indd 5 5.3.2008 9:01:08 Uhr 1.0 Introduction In recent decades – especially following the adoption of the Climate Convention in 1992 – the demand for observations of climate and climate change has steadily increased. For scientific conclusions on climate change, the attribution of anthropogenic influences and future climate scenarios, long-term, high-quality data series are essential.

Klima_S06_11_Einleitung.indd 6 5.3.2008 9:58:09 Uhr Background The recently published Fourth Assessment by around 2 °C and summer temperatures by Report of the Intergovernmental Panel on almost 3 °C. Precipitation levels are projected Climate Change (IPCC, 2007) summarizes the to rise by about 10% in winter and to fall current state of knowledge on climate change by about 20% in summer. In addition, the and its global impacts. From a global perspec- frequency of extreme precipitation events is tive, Switzerland is relatively seriously affected expected to increase, especially in the winter, by climate change. possibly leading to more frequent floods and By 2050, according to a recent report by debris flows in certain regions. Management the Swiss Advisory Body on Climate Change of climate change and its impacts thus repre- (OcCC, 2007), Switzerland will face autumn, sents a major challenge for the present and winter and spring temperatures to increase the future.

The climate system

The components of the climate system (IPCC, 2007). uction d intro

Since the publication of the previous IPCC of the UNFCCC (“Research and Systematic Assessment Report in 2001, researchers have Observation”) and in Article 10 of the subse- made significant progress in understanding the quent Kyoto Protocol. climate system, current changes in the climate and their impacts on humans and the environ- GCOS is co-sponsored by the World Meteo- ment. To a considerable extent, this improve- rological Organization (WMO), the Inter- ment in scientific understanding can be attri- governmental Oceanographic Commission of buted to substantial improvements in the data UNESCO, the UN Environment Programme base. (UNEP) and the International Council for Science (ICSU). GCOS is designed to ensure The close links between climate observation that the observations and information needed and climate research/modelling were recog- to address climate-related issues are obtained nized when the IPCC was first convened in and made available to all potential users. Build- the 1980s. This led to the establishment of the ing on existing networks and systems, GCOS Global Climate Observing System (GCOS), as encompasses the total climate system includ- well as to the adoption of the UN Framework ing observations of physical, chemical and bio- Convention on Climate Change (UNFCCC) in logical properties of the atmosphere, the ocean 1992. The aims and requirements of syste- and the land surface (see Figure). matic observation are specified in Article 5

Klima_S06_11_Einleitung.indd 7 12.3.2008 15:58:55 Uhr Analyses of the climatological time series d) Support the prediction of global climate collected within the GCOS framework provide change. a key foundation for reports by internatio- Climate predictions should consider not only nal climate experts (e.g. IPCC Assessment the forcings, as described in (b), and their Reports, WMO Assessment Reports on ozone). past history, but also the current state of the The Fourth IPCC Assessment Report makes climate system. Long-term climatological series reference to various papers concerning Swiss also play a key role in the calibration/validation climatological time series, e.g. for precipitation of climate models. (Schmidli and Frei, 2005), radiation (Philipona et al., 2005; Wild et al., 2005), snow (Scherrer et e) Project global climate change infor- al., 2004), glaciers (Zemp et al., 2005), perma- mation down to regional and national frost (Vonder Mühll et al., 2004) and pheno- scales. logy (Defila and Clot, 2001). Impacts and adaptation will be apparent mos- tly on national and local scales, underscoring According to the GCOS Second Adequacy the importance of climate information on that Report (WMO, 2003), systematic climate obser- level. Long-term observations are required vations should support the following applica- in order to develop models for local climate tions: scenarios and to understand the effects of the climate and climate variations on natural a) Characterize the state of the global systems (e.g. glaciers, river discharge, eco- climate system and its variability. systems). There is thus a special need for High priority is attached to the accuracy, homo- detailed local information about the variables geneity and continuity of data, so that climate described in (a) and for an increased density of signals are discernible from systematic biases, observations at the national level. e.g. caused by changes in observing systems over the years. To characterize the climate f) Characterize extreme events and assess system, many variables need to be observed their risk and vulnerability. simultaneously. Data for characterizing extreme events (e.g. floods, storms, heatwaves) are important for b) Monitor the forcing of the climate impact assessment, policy development and system, including both natural and anthro- adaptation. pogenic contributions. Over decades and centuries, variations in total To fulfil these requirements, GCOS has de- solar irradiance and in volcanic aerosols have fined a set of essential climate variables (Table been the main natural drivers of climate varia- 1). This selection takes into account the scien- bility and change. Anthropogenic contributions tific requirements as well as the measurability include greenhouse gases, aerosols and land of climate variables on the global scale. How- use changes. ever, additional variables are needed in order to understand the climate system as a whole. c) Support the attribution of the causes of There are important additional climate variables climate change. systematically measured in Switzerland that Along with systematic observations of the should also be included in the national climate state variables and climate drivers (“forcings”) observing system (GCOS Switzerland). described in (a) and (b), good models are required to be able to relate the expected change in state variables to the forcings.

Klima_S06_11_Einleitung.indd 8 5.3.2008 9:58:10 Uhr The specified applications require more infor- observing networks should be operated in mation than can be provided by the GCOS accordance with the GCOS Climate Monitoring global monitoring networks alone. Therefore, Principles (Table 2). Particular attention needs as noted in the GCOS Implementation Plan to be paid to, for example, metadata (Principle (WMO, 2004), coordination is required at the #3), quality assurance (#4) and data archival regional and especially the national level to im- (#10). In addition, a variety of historical obser- plement denser operational climate observing vations exist that are not yet available in digi- networks. tal form and should be digitized so as to further As far as possible, regional and national climate extend the most important time series.

Domain Essential Climate Variables

Air temperature, Precipitation, Air pressure, Surface radiation budget, Wind Surface speed and direction, Water vapour

Earth radiation budget (including solar irradiance), Upper air temperature, Atmospheric Upper air Wind speed and direction, Water vapour, Cloud properties

Carbon dioxide, Methane, Ozone, Other long-lived greenhouse gases, Aerosol intro d uction Composition properties, Pollen

Sea-surface temperature, Sea-surface salinity, Sea level, Sea state, Sea ice, Surface Current, Ocean colour, Carbon dioxide partial pressure Oceanic Temperature, Salinity, Current, Nutrients, Carbon, Ocean tracers, Sub-surface Phytoplankton

River discharge, Lake levels, Ground water, Water use, Isotopes, Snow cover, Glaciers and ice caps, Permafrost and seasonally-frozen ground, Albedo, Land Terrestrial cover, Leaf area index, Photosynthetic activity, Biomass, Fire disturbance, Phenology

Table 1. Essential climate variables as listed in the GCOS Second Adequacy Report (WMO, 2003), together with additional variables of relevance for Switzerland (in italics).

Switzerland has a long tradition in the obser- forest ecosystem, forest fires, phenology). The vation of climate. Systematic observation pro- data collected are reviewed according to strin- grammes established by Swiss institutions gent quality criteria and transmitted to world make a significant contribution to the global data centres, where they are made available climate observing system. The most important to the international scientific community for systematic observations concern the surface integrated analysis. In this connection, the and upper air climate, Earth radiation budget, data and calibration centres operated by Swiss atmospheric trace gases, aerosols and pollen, institutions play an important role in the stan- hydrology, snow, glaciers and permafrost, and dardization of data and the international data climate-related biosphere variables (land use, exchange.

Klima_S06_11_Einleitung.indd 9 5.3.2008 9:58:10 Uhr Following the ratification of the Kyoto Protocol term planning to ensure continuous and by the Swiss Parliament in summer 2003, the representative observations, e.g. by identifying national GCOS coordination was strengthened the risk of discontinuity ahead of time and by the Federal Office of Meteorology and engaging in remedial action. As far as possible, Climatology (MeteoSwiss). On 1 February 2006, new measurement techniques are also consid- the Swiss GCOS Office was established, ered in the integrated observation system. building on the former GCOS Focal Point at In addition, the Swiss GCOS Office identifies MeteoSwiss. The Swiss GCOS Office is res- resource-related problems affecting the opera- ponsible for coordinating climatological obser- tion of international data and calibration cen- vations carried out in Switzerland by federal tres in Switzerland and provides financial and offices, research institutes and universities/ technological support for selected observa- institutes of technology. This includes long- tions abroad.

GCOS Climate Monitoring Principles

1. The impact of new systems or changes to existing systems should 6. Uninterrupted station operations and observing systems should be be assessed prior to implementation. maintained.

2. A suitable period of overlap for new and old observing systems 7. A high priority should be given to additional observations in data- should be required. poor regions and regions sensitive to change.

3. The results of calibration, validation and data homogeneity assess- 8. Long-term requirements should be specified to network designers, ments, and assessments of algorithm changes, should be treated operators and instrument engineers at the outset of new system with the same care as data. design and implementation.

4. A capacity to routinely assess the quality and homogeneity of data 9. The carefully-planned conversion of research observing systems to on extreme events, including high-resolution data and related long-term operations should be promoted. descriptive information, should be ensured. 10. Data management systems that facilitate access, use and inter- 5. Consideration of environmental climate-monitoring products and pretation should be included as essential elements of climate assessments, such as IPCC assessments, should be integrated into monitoring systems. national, regional and global observing priorities.

Table 2. The ten principles adopted by the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) through decision 5/CP.5 at COP-5 in November 1999, and by the Congress of the World Meteorological Organization (WMO) through Resolution 9 in May 2003.

Motivation Switzerland has a long tradition of climate The aim of this report is to present a complete observations. The long-term climatological inventory of climatological time series in Swit- data series are of high historical signifi- zerland, and to identify significant time series cance for the institutions concerned and are whose continuation is threatened by inade- of major scientific value both for Switzer- quate resources. land and worldwide. Nonetheless, the conti- The report primarily takes stock of the current nuation of valuable time series is frequently situation. In cases where a legal basis or clear- under threat. In addition, long-term observa- ly defined responsibilities are lacking, plans for tions are generally not supported by research a future monitoring network should be elabo- funding. rated and accompany requests for funding.

Klima_S06_11_Einleitung.indd 10 5.3.2008 9:58:10 Uhr Klima_S06_11_Einleitung.indd 11 tinuation. con- their to risks identifying and series gical climatolo- documenting of aim the with land officesfederal and institutes Switzer-in based researchtechnology, of universities/institutes GCOS Swiss the and ProClim 2006, of spring the In Procedure operated by Swiss institutions. It also describes are that variables climate essential of centres data international the presents 4 Chapter isotopes,phenology). Switzerland (pollen, included three other variables of relevance for Tablealso in and listed 1 variables climate tial observations. The survey covered all the essen- 3) (Chapter terrestrial and 2) (Chapter pheric atmos- of headings general the under land, Switzer- in measured variables climate the of account an give chapters two following The Structure main criteria specified were that a series should: gical stations (Müller, 1980; WMO, 1997). The climatolo- of selection of the for basis studies similar the on defined were criteria The fie efre a uvy among survey a performed Office the national climate observing system ( system observing climate national the of the report and looks ahead to the future of conclusions main the summarizes 6 Chapter tutions. insti- Swiss by out carried and/or funded are tological observations outside Switzerland that clima- valuable on focuses 5 Chapter tres). observation international calibration (e.g. cen- climate for importance major of are that land Switzer- in based centres international other to ensure continuedoperationofstations. indicate their requirements for funding in order to asked also were Respondents metadata. of availability and quality data sentativeness, repre-geographical centres, agreements/data international in participation included criteria methods. variables/observation The climate secondary introduced recently concern (c) or abroad, series comparable than years, longer be 50 (b) than more of period a cover (a) Switzerland). GCOS

5.3.2008 9:58:11 Uhr

11 introduction 2.1 Air temperature Temperature is a key indicator of changes in the climate. As long time series of measurements of ground-level temperature in Switzerland are available, dating back to the mid-19th century, long-term trends can be analysed. These analyses provide a sound basis for investigating the contribution of anthropogenic factors to global warming.

2.5

2.0

1.5

1.0

0.5

0.0

deviation [°C] -0.5

-1.0

-1.5

-2.0 1880 1900 1920 1940 1960 1980 2000

years above mean 1961 –1990 years below mean 1961 –1990 20-year weighted mean (Gaussian lowpass filter)

Measurements in Switzerland Air temperature at ground level is now mea- As well as meeting climatological needs, § Legal basis sured by MeteoSwiss at almost 130 stations. the MeteoSwiss stations provide services for Under the Federal Act on Meteorology and In some cases, these systematic measure- other user groups, e.g. warnings, aviation Climatology (MetG, SR 429.1), the federal ments extend as far back as December 1863, weather, and data for civil protection, agricul- authorities are required to record meteoro- when Switzerland’s first nationwide meteoro- ture and tourism. The network of stations has logical and climatological data continuous- logical observation network came into opera- been continually reviewed on the basis of anal- ly throughout the territory of Switzerland. tion. Some monthly values are also available as yses of requirements (Measurement Concepts They are also to participate in the record- paper records from earlier periods, e.g. for 1980 and 2010), and the distribution of sta- ing, exchange and analysis of international Basel (from 1755), Geneva (1768) or Grand St. tions across the country and various altitudes meteorological and climatological data. In Bernard (1817). Since 1980, a number of these has been optimized. addition, they are responsible for the pro- stations have been automated (ANETZ). The At each automatic MeteoSwiss station, vision of climatological information and for roughly 70 ANETZ stations are currently being values are recorded every 10 minutes and the implementation of measures contrib- upgraded in line with the latest technological transmitted to the central database in Zurich. uting to the long-term preservation of an developments, and the other stations in the The temperature observations are used to cal- intact environment. Under the Federal network are also to be converted to automatic culate hourly, daily, monthly and annual means, Ordinance on Meteorology and Climatology operation by 2012 (SwissMetNet project). together with medians, absolute extremes and (MetV, SR 429.11), the Federal Office of Alongside the MeteoSwiss stations, air tem- numerous other parameters, such as frost days Meteorology and Climatology MeteoSwiss is perature is also measured at numerous other or heat days. responsible for these tasks. weather stations by cantonal and communal In order to understand changes in atmos- authorities and private operators. pheric temperature conditions, soundings are 12

Klima_S12_13_Temperatur.indd 12 5.3.2008 10:13:16 Uhr Long time series and their importance At many of the sites chosen in 1863, stations and homogenized. In order to increase the are still in operation today. In the NORM90 density of stations, particularly in the Central project, for each of Switzerland’s twelve major Alpine region characterized by large differences climate regions, a station was selected where in altitude, 16 additional stations were selected measurement data have been collected since with time series from at least 1900 (exception: at least 1900. These long time series were Jungfraujoch only from 1930). These stations analysed for artificial discontinuities and trends of the greatest climatological importance (28 caused, for example, by station relocation, in all) were designated as the Swiss National change of instrumentation and calibrations, Basic Climatological Network (NBCN).

Temperature in Switzerland 1864 – 2006 Deviation of the annual mean from the 1961–1990 average

2.5 The deviation of the annual mean

2.0 temperature in Switzerland from the multiyear average (norm 1961– 1.5 1990) offers a striking example of 1.0 climate change. The linear trend OBSERVATIONS between 1864 and 2005 is + 1.1°C 0.5 per 100 years, yielding a total warm- HERIC

0.0 ing of +1.5 °C from 1864 to 2005 p

deviation [°C] -0.5 (Begert et al., 2005). From a global perspective, temperature is the vari- ATMOS -1.0 able best suited for demonstrating -1.5 the anthropogenic influence on the climate system. Long-term tempe- -2.0 rature series are therefore crucial for 1880 1900 1920 1940 1960 1980 2000 the observation, analysis and quan- years above mean 1961 –1990 tification of climate change. years below mean 1961 –1990 20-year weighted mean (Gaussian lowpass filter)

International Integration Within the GCOS Surface Network (GSN), of the stations, the data are additionally made temperature and precipitation are measured available on a daily basis. In Switzerland, two at around 1000 stations worldwide and trans- NBCN stations were selected as GSN stations mitted on a monthly basis to the GSN Moni- – Säntis and Grand St.Bernard. Seven NBCN toring Centres at the Japanese Meteorologi- stations (Säntis, Grand St.Bernard, Geneva, cal Agency (JMA) in Tokyo (temperature) and Sion, Basel, Zurich and Lugano) belong to the the German Meteorological Service (DWD) in Regional Basic Climatological Network (RBCN) Offenbach (precipitation). At about a quarter of the WMO. Swiss National Basic Climatological Network NBCN. 2 stations belong to the GCOS Surface Network GSN (red) and 7 to the Regional Basic Climatological Network (red + blue).

carried out several times a day in addition to Resources required ground-based monitoring. Increasingly, these Operation of the NBCN stations is assured cover the parallel measurements required vertical temperature profiles are supplemented under the legal mandate of MeteoSwiss. for a 3-year period to meet GSN standards. by ground- and satellite-based remote sensing However, in the case of station renewals, it Additional funds need to be set aside for such measurements and in-situ sensors mounted on has been shown that budgets do not always extraordinary tasks. commercial aircraft ( 2.7 Water vapour). 13

http://www.meteoswiss.admin.ch/web/en/climate/climate_since_1864/tt_rr_1864.html

Klima_S12_13_Temperatur.indd 13 5.3.2008 10:13:20 Uhr 2.2 Precipitation Precipitation, together with temperature, is a key indicator of changes in the climate. As long time series are available for precipitation in Switzerland, dating back to the mid-19th century, long-term analyses can be performed. These are particularly valuable for assessing the effects of climate change on the water cycle and water balance.

1.61.6

1.41.4

1.21.2

1.01 ratio

0.80.8

0.60.6

0.40.4 1880 1900 1920 1940 1960 1980 2000

years above mean 1961–1990 years below mean 1961–1990 20-year weighted mean (Gaussian lowpass filter)

Measurements in Switzerland Precipitation is now measured by MeteoSwiss culate total precipitation on an hourly, daily, § Legal basis at more than 400 stations, some of which have monthly and yearly basis. At the NIME stations, Under the Federal Act on Meteorology and been in operation since December 1863. In a the amount of precipitation is recorded once Climatology (MetG, SR 429.1), the federal number of cases, the measurements go back a day by the station operator, and records are authorities are required to record meteoro- to the 18th century, although there are consid- sent in by post once a month. The NIME mea- logical and climatological data continuous- erable gaps in some of the time series. Since surements are thus not available in real time. ly throughout the territory of Switzerland. 1980, a number of these stations have been To measure precipitation in mountainous They are also to participate in the record- converted to automatic operation (ANETZ). areas, so-called totalizers are used. A total- ing, exchange and analysis of international The roughly 70 ANETZ stations are currently izer generally measures precipitation for the meteorological and climatological data. In being upgraded, and about 60 other stations water year (October 1 to September 30). addition, they are responsible for the pro- (KLIMA, ENET) are also being automated Additional readings are sometimes taken vision of climatological information and for (SwissMetNet project). While the remaining during the year. However, owing to the poor the implementation of measures contrib- precipitation stations (NIME, totalizers) are not accessibility of many totalizers, no more uting to the long-term preservation of to be automated at present, the distribution of than one additional reading (in the spring) is an intact environment. Under the Federal these stations is to be investigated in detail and usually taken. This at least makes it possible to Ordinance on Meteorology and Climatology reviewed in the coming years under a Precipi- determine the relative proportions of winter (MetV, SR 429.11), the Federal Office of tation Concept. and summer precipitation. Meteorology and Climatology MeteoSwiss is At each automatic MeteoSwiss station, precip- In addition to in-situ measurements, precip- responsible for these tasks. itation is collected and measured at 10-minute itation is also calculated indirectly on the intervals. These measurements are used to cal- basis of radar reflectivity with 3 precipitation 14

Klima_S14_15_Niederschlag.indd 14 5.3.2008 10:35:44 Uhr Long time series and their importance systematic recording of precipitation in swit- station is precipitation not recorded. to com- zerland began in 1863 with the operation of, plement the swiss nbcn stations, the most im- initially, about 70 weather stations equipped portant nime stations with daily measurements with a precipitation gauge. the total number are to be defined under the precipitation con- of stations subsequently rose sharply, and by cept. in mountainous areas, the totalizer data around 1900 precipitation was being measured represent important additional precipitation daily at more than 300 locations. at many of series with a low temporal resolution. From a the sites originally selected, stations remain in climatological perspective, 8 of the totalizers operation today. the most important sites are are to be protected with priority 1 and another 27 of the 28 swiss nbcn stations ( 2.1 air 27 with priority 2. temperature); only at the Jungfraujoch nbcn

Precipitation in Zurich 1864 – 2006 ratio of the annual total to the 1961–1990 average

1.61.6 Ratio of the annual total precipitation for Zurich to the multiyear

1.41.4 average (norm 1961–1990) from 1864 to 2006. The data series shows

1.21.2 a significant linear trend, with an increase of approximately 10% over 100 years. In particular, winter 1.01 ratio precipitation has increased (Begert et al., 2005). Long series provide a 0.80.8 basis for understanding the broader atmospheric observations context and permit conclusions con- 0.60.6 cerning trends and recurrence intervals for extreme events (heavy rain- 0.40.4 fall and dry periods). Indirectly, they 1880 1900 1920 1940 1960 1980 2000 are valuable for planning flood pro- years above mean 1961–1990 tection measures and developing years below mean 1961–1990 regional climate scenarios. 20-year weighted mean (Gaussian lowpass filter)

International integration precipitation data from the Gcos surface precipitation radar networks in europe are co- network (Gsn) stations säntis and Grand st. ordinated by the eUmetnet operational pro- bernard are transmitted to the Gsn moni- gramme for the exchange of weather radar toring centre at the DWD, and the Wmo information (opera). all three swiss precip- receives data from the regional basic cli- itation radars are integrated into the opera matological network (rbcn) stations säntis, programme. in addition, the interreG projects Grand st.bernard, Geneva, sion, basel, Zurich verbano and Franche-comté are improving Red: Stations of the Swiss National Basic Clima- and Lugano. the precipitation data from all precipitation radar coverage in the border tological Network NBCN; green: MeteoSwiss pre- meteoswiss stations are also transmitted to regions with italy and France respectively. cipitation radars; blue: 8 totalizers of greatest cli- the Gsn monitoring centre for precipitation in matological significance. offenbach.

radars (La Dôle, albis and monte Lema). these stations have been in operation since 1961 (La Resources required Dôle, albis) or 1993 (monte Lema), and the operation of the nbcn and nime stations totalizers of greatest climatological significance data have been systematically archived in digi- is assured under the legal mandate of are only guaranteed in the short term, as about tal form since 1991. the precipitation radar meteoswiss. however, budgets do not always half of the stations are funded by third parties; data thus represent potential long time series cover the parallel measurements required for in addition, the commercial importance of the for future analyses. a 3-year period to meet Gsn standards. the totalizer network is declining. 15

http://www.meteoswiss.admin.ch/web/en/climate/climate_since_1864/tt_rr_1864.html

Klima_S14_15_Niederschlag.indd 15 12.3.2008 15:59:25 Uhr 2.3 Air pressure Air pressure is an important component of the climate system, characterizing both local and large-scale atmospheric circulation. It is one of the key variables for backward modelling of long- term global meteorological datasets. Long-term observation of air pressure permits conclusions concerning, for example, variations in meteorological conditions.

2.5 2.5

2.0 2.0

1.5 1.5

1.0 1.0

0.5 0.5

0.0 0.0

-0.5−0.5 deviation [hPa] -1.0−1.0

-1.5−1.5

-2.0−2.0

-2.5−2.5 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

years above mean 1961–1990 years below mean 1961–1990 20-year weighted mean (Gaussian lowpass filter)

Measurements in Switzerland Surface pressure is now measured by the associated station relocations. As air pres- § Legal basis MeteoSwiss at 90 stations. Systematic measure decreases with increasing elevation, mea- Under the Federal Act on Meteorology and surements began in 1864, when Switzerland’s surements are strongly dependent on the Climatology (MetG, SR 429.1), the federal nationwide meteorological observation net- altitude of the station. To allow measurements authorities are required to record meteoro- work came into operation. Early records for from different stations to be compared, the logical and climatological data continuous- individual sites such as Basel or Geneva go readings are converted to sea level pressure. At ly throughout the territory of Switzerland. back to the 18th century. However, as these the automatic stations, air pressure is measured They are also to participate in the record- data have never been processed, they are either every 10 minutes, and these values are used ing, exchange and analysis of international not available in digital form or only as monthly to calculate hourly, daily, monthly and annual meteorological and climatological data. In averages. means. As well as being highly important for addition, they are responsible for the pro- Historically, air pressure was measured with climate observation, these data are essential for vision of climatological information and for mercury barometers. Since the monitoring net- description of the current state of the atmos- the implementation of measures contrib- work was automated, new methods of mea- phere, for weather forecasting and for model- uting to the long-term preservation of surement have increasingly been used. At the ling. Alongside the MeteoSwiss stations, air an intact environment. Under the Federal automatic stations, air pressure is measured pressure is also measured at a number of Ordinance on Meteorology and Climatology by means of an aneroid barometer – a metal other weather stations by cantonal and (MetV, SR 429.11), the Federal Office of box which expands or contracts in response communal authorities and private operators. Meteorology and Climatology MeteoSwiss is to changes in air pressure. The introduction of Surface pressure is one of the climate vari- responsible for these tasks. a new type of instrument caused less signifi- ables that cannot yet be measured opera- cant inhomogeneities in the data series than tionally by satellites. The problem is primarily one 16

Klima_S16_17_Luftdruck.indd 16 5.3.2008 10:45:10 Uhr Long time series and their importance From the Swiss meteorological network devel- ments, as most of the stations have record- oped since 1863, 28 stations of climatological ed air pressure data continuously since 1863. significance were selected so that Switzerland’s It is not planned to homogenize all of the 28 climate would be represented and character- time series, since air pressure shows strong ized as well as possible ( 2.1 Air temperature). regional correlations and the processing of These Swiss national Basic Climatological net- a selection of nBCn series is thus sufficient to work (nBCn) stations also provide the most describe long-term trends in Switzerland. important long series of air pressure measure-

Air pressure in Zurich 1959 – 2006 Deviation of the annual mean from the 1961–1990 average

2.5 2.5 Deviation of the annual mean air S n pressure in Zurich from the 1961– 2.0 2.0 1990 average between 1959 and 1.5 1.5 2006. The trend correlates with that 1.0 1.0 observed for air temperature, indi- OBSERVATIO 0.5 0.5 cating the relationship between the frequencies of atmospheric circula- 0.0 0.0 HERIC

tion patterns and regional climate p -0.5−0.5 variability. Long-term air pressure deviation [hPa] -1.0−1.0 series are valuable for the descrip- ATMOS -1.5−1.5 tion of long-term variations in the frequency of atmospheric circula- -2.0−2.0 tion patterns. In addition, they are -2.5−2.5 the key input variable for the global 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 and regional reanalyses used in the years above mean 1961–1990 validation of climate models. years below mean 1961–1990 20-year weighted mean (Gaussian lowpass filter)

International integration Of the Swiss nBCn stations, Säntis, Grand temperatures, precipitation) of the GSn. St.Bernard, Geneva, Sion, Basel, Zurich and Measurement of this variable is, however, a Lugano belong to the Regional Basic Clima- target requirement. At the WMO, efforts are tological network (RBCn) of the WMO, which also under way to establish an international comprises 2600 surface stations worldwide. surface pressure database. In an initial global Two of the Swiss stations – Säntis and Grand dataset, measurements of surface pressure St.Bernard – also belong to the GCOS Sur- (including Swiss RBCn data) have been Swiss National Basic Climatological Network face network (GSn), which includes 980 processed for the years 1850–2004. This data- NBCN. 2 stations belong to the GCOS Surface stations worldwide. Air pressure measurement set comprises global data on a monthly basis Network GSN (red) and 7 to the Regional Basic is not one of the minimum requirements (mean with a spatial resolution of about 500km. Climatological Network RBCN (red + blue).

Resources required Operation of the nBCn stations is assured has been shown that budgets do not always under the legal mandate of MeteoSwiss. cover the parallel measurements required for a of accuracy, since the daily fluctuations to be However, in the case of station renewals, it 3-year period to meet GSn standards. measured are much smaller than the average air pressure values. 17

http://www.meteoswiss.admin.ch/web/en/climate/climate_norm_values.html

Klima_S16_17_Luftdruck.indd 17 5.3.2008 10:45:13 Uhr 2.4 Sunshine duration In addition to temperature, precipitation and air pressure data, other meteorological measurements are required as indicators of changes in the climate. Among the most important additional variables recorded at weather stations are wind speed and direction, humidity, sunshine duration, global radiation, cloud cover and snow.

1.41.4

1.31.3

1.21.2

1.11.1 ratio

1.01

0.90.9

0.80.8 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

years above mean 1961–1990 years below mean 1961–1990 20-year weighted mean (Gaussian lowpass filter)

Measurements in Switzerland The variables of greatest climatological im- sure ( 2.3 Air pressure), this chapter describes § Legal basis portance are now measured by MeteoSwiss the other important meteorological measure- Under the Federal Act on Meteorology and at almost 130 stations. In some cases, these ments – wind speed and direction, humidity Climatology (MetG, SR 429.1), the federal systematic measurements extend as far back and sunshine duration. Global radiation is cov- authorities are required to record meteoro- as December 1863, when Switzerland’s first ered together with other radiation measure- logical and climatological data continuous- nationwide meteorological observation net- ments in section  2.5 Radiation, cloud cover ly throughout the territory of Switzerland. work came into operation. Since 1980, a in section  2.6 Clouds, and snow in section They are also to participate in the record- number of these stations have been auto-  3.6 Snow cover. ing, exchange and analysis of international mated (ANETZ). The roughly 70 ANETZ sta- At the ANETZ stations, humidity is measured meteorological and climatological data. In tions are currently being upgraded in line every 10 minutes (current value) and sunshine addition, they are responsible for the pro- with the latest technological developments, duration (accumulated value) at 10-minute vision of climatological information and for and the other stations in the network are also intervals. Wind speed/direction is measured the implementation of measures contrib- to be converted to automatic operation by continuously and on this basis mean values uting to the long-term preservation of 2012 (SwissMetNet project). Alongside the and gustiness are transmitted every 10 minutes. an intact environment. Under the Federal MeteoSwiss stations, some of the essential The 10-minute values are used to calculate the Ordinance on Meteorology and Climatology climate variables are also measured at numer- means for wind speed/direction and humidity, (MetV, SR 429.11), the Federal Office of ous other weather stations by cantonal and and the total values for sunshine duration. Meteorology and Climatology MeteoSwiss is communal authorities and private operators. The surface measurements of wind speed/ responsible for these tasks. As well as temperature ( 2.1 Air temperature), direction and humidity are supplemented precipitation ( 2.2 Precipitation) and air pres- by in-situ observations (soundings, airborne 18

Klima_S18_19_Sonnenscheindauer.indd 18 12.3.2008 15:59:55 Uhr Long time series and their importance A permanent Swiss monitoring network was direction were measured three times a day. established in the second half of the 19th cen- For this reason, wind data have only been tury. Recently, the 28 stations of the greatest systematically analysed since the 1980s. In climatological significance have been designat- addition to the 12 homogeneous tempera- ed as the Swiss National basic Climatological ture and precipitation series dating back to Network (NbCN) ( 2.1 Air temperature). In 1864, homogeneous time series are now most cases, time series for humidity go back available from 1959 for air pressure, sunshine to 1863. Measurements of sunshine duration duration, vapour pressure and cloud cover, began some years later, and only at select- and from 1981 for global radiation and wind ed locations. before the network was auto- speed. mated (starting in 1981), wind speed and

Sunshine duration in Zurich 1959 − 2006 Ratio of the annual total to the 1961–1990 average

1.41.4 Homogenized data on sunshine duration in Zurich from 1959 to

1.31.3 2006. Homogenization is required because measurement conditions SERVATIONS 1.21.2 are not generally constant for long b O time series. Changes in measurement conditions (e.g. station relo- 1.11.1 ERIC ratio cations, environmental changes, h new instruments) can lead to abrupt 1.01 or gradual increases or decreases in ATMOSP readings, confounding trend analy- 0.90.9 sis of time series. Statistical methods and assessments of station history 0.80.8 are used in an attempt to identify 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 and correct inhomogeneities in time years above mean 1961–1990 series (Begert et al., 2003). years below mean 1961–1990 20-year weighted mean (Gaussian lowpass filter)

International integration Of the Swiss NbCN stations, Säntis, Grand temperature, precipitation, air pressure, snow St.bernard, Geneva, Sion, basel, Zurich and depth, sunshine duration, relative humidity Lugano belong to the Regional basic Climato- and cloud cover) from around 2000 stations logical Network (RbCN) of the WMO. and checked for inhomogeneities. This makes As part of the EU ENSEMbLES project, a Euro- it possible to minimize the influence of varia- pean dataset was compiled for various obser- tion in measurement conditions over time on vational series (minimum, maximum and mean subsequent trend analyses. Swiss National Basic Climatological Network NBCN. 2 stations belong to the GCOS Surface Network GSN (red) and 7 to the Regional Basic Climatological Network RBCN (red + blue).

Resources required Operation of the 28 Swiss NbCN stations is been shown that budgets do not always cover measurements) and increasingly also by meas- assured under the legal mandate of MeteoSwiss. the required 3-year parallel measurements. urements from ground- and satellite-based however, in the case of station renewals, it has remote sensing instruments ( 2.7 Water vapour). 19

http://www.meteoswiss.admin.ch/web/en/climate/climate_norm_values.html

Klima_S18_19_Sonnenscheindauer.indd 19 5.3.2008 10:55:17 Uhr Klima_S20_21_Strahlung.indd 20 2.5 § 20 Legal basis lbl topee ac ( Watch Atmosphere Global rme n codne ih h Federal the with accordance in gramme Council Decree of25November 1994. the in participates and 0.429.01) World Organization the Meteorological of member a is Switzerland addition, In tasks. these for responsible is MeteoSwiss Climatology and Meteorology of Office Federal the 429.11), SR (MetV, Ordinance on Meteorology and Climatology Federal the Under projects. research plied ap- conduct to and climatology and logy meteoro- theoretical support to are They Switzerland. of territory the throughout ly continuous- data climatological and logical meteoro- record to required are authorities federal the 429.1), SR (MetG, Climatology and Meteorology on Act Federal the Under in theclimate. changes of study detailed a allow and measurable are changes These budget. radiation the in changes as manifested directly greenhouse gases and anthropogenic aerosols on the climate are of effects The climate. in differences regional and seasonal for accounting system, climate the in factor main the is Radiation Radiation GAW WMO pro- ) WMO ( SR

teml rdain rm h Erhs surface Earth’s the from radiation (thermal) longwave upward and radiation shortwave arerecorded. threeAt reflectedsites, these of radiation (atmospheric) longwave downward and radiation (solar) shortwave downward the all At work. ( Budget Radiation Surface Alpine in 1995mented another the 10by of stations as known network, lies south and of Locarno-Monti the Alps. This Plateau Central the on is station Payerne the while Alps, the in situated are stations Davos and Jungfraujoch The spectrum. tromagnetic elec- the of portion infrared the to visible the of radiation fluxes from the ultraviolet through measurement the for stations dedicated four operates MeteoSwiss stations, SwissMetNet) ( network automatic the at ation radi- global of monitoring the to addition In Measurements inSwitzerland pei Rdain oioig, a supple- was Monitoring), Radiation spheric CHARM CHARM and Sis Atmo- (Swiss ASRB ANETZ ASRB stations, , now , ) net- ) Watch ( line Surface Radiation Network ( Network Radiation Surface line Base- the to belongs also station Payerne The Bern. The Bern. the involved in the tent of the atmosphere. Various institutions are con- vapour water and depth optical aerosol the determine to order in resolution temporal uously with the greatest precision and at a high contin- measuredare fluxes radiation spectral and with accordance in measuredare fluxes radiation longwave and global) and diffuse ( budget radiation surface global the studies recorded. additionally are are attached to the lite products. In the Eumetsat Satellite Applica- ments are also used for the validation of satel-  4.2 PMOD/WRC GAW BSRN GAW guidelines. In addition, individual addition, In guidelines. CHARM/BSRN ). To this end, shortwave (direct, (direct, shortwave end, Tothis ). ) programme. CHARM , the WMO ETH network: MeteoSwiss, and and the University of Global Atmosphere CHARM ASRB BSRN 5.3.2008 11:17:23 Uhr and measure- ), which ), BSRN ASRB

radiation ﬂuxes [W/m 2 ] 270 275 280 285 365 370 375 380 330 335 340 345 10 10 90 95 0 5 Solar netradiation Total surface absorbedradiation Thermal downwardradiation Thermal upwardradiation 9619 0020 0419 9820 022004 2002 2000 1998 1996 2004 2002 2000 1998 1996 Klima_S20_21_Strahlung.indd 21 Radiation fluxesinW/m dated specificallyfortheAlps. vali- and data satellite Europeanfrom derived SAF ( Monitoring Climate for Facilities tion site, there isalsoaASRBstation. CHARM every At budget. radiation surface the of components individual monitor (blue) work and ASRB net- (red) The stations of the CHARM radiation ﬂuxes [W/m 2 ] Radiation budgetintheAlps 1995 −2004 330 335 340 345 365 370 375 380 270 275 280 285 10 10 ) project, a variety of radiation products are 90 95 0 5 Solar netradiation Total surface absorbedradiation Thermal downwardradiation Thermal upwardradiation 9619 0020 0419 9820 022004 2002 2000 1998 1996 2004 2002 2000 1998 1996 2 CM- o ln-em oioig n poie relia- provide and monitoring long-term for Data are supplied to the World Radiation Data Radiation Monitoring Centre ( Centre Monitoring Radiation

carried out at ten been have measurements radiation addition, respectively.In 2001 and 1996in established were sites Locarno-Monti and Jungfraujoch Payerne the at and measurements were initiated at Davos in 1991 the Under Long timeseriesandtheirimportance Resources required the with Europeaninitiative a in studied being of climatology BSRN GAW ( Centre integration International for specifically budget radiation the in trends study to possible it making data, radiation ble CHARM their operation is assured both under the legal stations into the MeteoSwiss-run SwissMetNet, With the integration of the WRC the and MeteoSwiss of participation http://www.meteoswiss.ch/web/en/climate/global_climate_monitoring/GAW_CH_Allg.html . The . in Zurich. Under Zurich. in World Data Centres, and to the World the to and Centres, Data World WRDC and BSRN CHARM ASRB ) in St.Petersburg, one of five of one St.Petersburg, in ) UV has been designated as the as designated been has ASRB aito oe Erp is Europe over radiation BSRN ewrs r designed are networks rgam, radiation programme, stations since 1995. The COST station in station 1992. The CHARM Action 726, the 726, Action WRMC and ) of the of ) PMOD ASRB /

total of 38 of total 1995 ( has been measured at measured been has Jungfraujoch and Locarno and two and Locarno and Jungfraujoch four The ual stations. individ- at recently began only measurements these although sites, four at recorded also GAW programme. mandate of MeteoSwiss and through the Swiss of validation routine for station official an also within radiation surface for network baseline global comparison with other variables. ANETZ at located are Weissfluhjoch) (Cimetta, tions climate variablesusingsatellitedata. meteorological services, which aims to monitor European several involving project joint a is the Alps. Outgoing radiation components are components radiation Outgoing Alps. the CM-SAF radiation and thus changes in the green- the in changes thus and radiation longwave downward study to possible it make measurements these conditions, free strong cloud-dependent variation. In cloud- show radiation longwave downward and solar Net radiation. longwave and upward temperature in increase an ducing pro- thereby rising, is radiation absorbed total how show Alps the in network ASRB the from measurements budget Radiation house effect (Philipona etal.,2005). house effect (Philipona  (now SwissMetNet) sites, permitting sites, SwissMetNet) (now GCOS 2.8 Ozone). CHARM products. The BSRN . The Payerne station is one of a of one is station Payerne The . stations ( stations ttos aen, Davos, Payerne, stations CHARM EUMETSAT  4.2 BSRN) and is and BSRN) 4.2 stations since stations UV ASRB radiation

CM-SAF sta-

5.3.2008 11:17:27 Uhr

21 ATMOSPHERIC OBSERVATIONS 2.6 Clouds The interaction between radiation and clouds remains one of the major sources of uncertainty in climate models. High priority is therefore accorded to measurement of the spatial distribution and microphysical properties of clouds. For this purpose, soundings and ground-based observations can be ideally supplemented by satellite data.

Measurements in Switzerland At the MeteoSwiss monitoring stations (except ic variables such as cloud cover, cloud type § Legal basis for airports), cloud variables are not measured (classified by various spectral properties), Under the Federal Act on Meteorology and instrumentally, but estimated by observers at cloud-top height and cloud wind, as well as Climatology (MetG, SR 429.1), the federal regular intervals. Currently, 54 stations belong microphysical properties such as optical depth, authorities are required to record meteoro- to the visual observation network (OBS). The droplet size distribution, cloud-top phase and logical and climatological data continuously variables recorded include cloud cover, cloud liquid water content. Among the most im- throughout the territory of Switzerland. This type, cloud height, visibility, and present and portant sensors for cloud observation over includes records of clouds in the atmosphere past weather. Observations are made at least Europe are – on polar-orbiting satellites – and the radiation balance at the top of the three times a day and transmitted by laptop. AVHRR (onboard NOAA), MODIS and MISR atmosphere. The federal authorities are also At the airports, in addition to human observ- (onboard Terra) and MERIS (onboard Envi- to participate in the recording, exchange and ers, present weather sensors are used to meas- sat), and – on geostationary satellites – MVIRI analysis of international meteorological and ure a number of cloud variables (e.g. ceilo- (onboard Meteosat first-generation satellites) climatological data. Switzerland is a member meter for cloud-base height) and visibility and SEVIRI (onboard Meteosat second-genera- of the European Organisation for the Exploi- (transmissometer). tion satellites). tation of Meteorological Satellites EUMETSAT Comprehensive recording of the spatial extent The Earth Radiation Budget is the balance be- (SR 0.425.43). Under the Federal Ordinance and high temporal variability of clouds, includ- tween incoming solar radiation and outgoing on Meteorology and Climatology (MetV, SR ing their microphysical properties, has only longwave and reflected shortwave radiation 429.11), the Federal Office of Meteorology been possible since the first weather satellites at the top of the atmosphere. This value can and Climatology MeteoSwiss is responsible were launched in the 1950s. Satellite measure- only be directly determined by satellite meas- for these tasks. ments can be used to determine macroscop- urements. No systematic analyses of satellite 22

Klima_S22_23_Wolken.indd 22 5.3.2008 11:35:55 Uhr Long time series and their importance Visual observations from the 28 Swiss Natio- NORM90 project, in addition to sunshine dura- nal Basic Climatological Network (NBCN) station, cloud data from eight conventional NBCN tions ( 2.1 Air temperature) go back to the stations (Andermatt, Bad Ragaz, Chaumont, 19 th century, as do meteorological measure- Château d’Oex, Elm, Grächen, Meiringen and ments at many stations. However, in most Sils Maria) were homogenized from 1961 on- cases the data have not yet been homoge- wards. At certain NBCN stations (e.g. Engel- nized; i.e. they may contain inhomogeneities berg, Davos), the continuation of visual obser- resulting from different observers, changing vations is not guaranteed. observation times or station relocations. In the

Total cloud cover in the Alps 1989 − 2003 Area-averaged monthly total cloud cover from satellite data and surface observations

Monthly cloud cover from satellite 10 0 data (NOAA/AVHRR) and surface observations (SYNOP), 1989–2003. The curves represent spatial av- 80 erages for the Alps as a whole OBSERVATIONS (blue; 46-47.8 N, 8-14 E) and for the territory of Switzerland (red; 46-

60 HERIC

47.5 N, 6.5-10 E). Also given for p the Alps are the mean difference d (satellite measurement minus cloud cover [%] 40 ATMOS SYNOP), the standard deviation s of the differences and the correlation 20 coefficient c. This analysis is part of the German Aerospace Center (DLR) d = -1.0% s = 8.2% c = 0.75 European Cloud Climatology (ECC) 0 study (Meerkötter et al., 2004). 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 Switzerland (Sat) Alps (Sat) Alps (SYNOP)

International integration In addition to total cloud cover, the Euro- matology analysis based on satellite data col- pean Cloud Climatology (ECC) project included lected since 1983. However, the dataset for the variables “coverage of low, medium-high, Europe in the initial years includes a number of high, and thin clouds”, “liquid and ice water major inhomogeneities which need to be duly content”, “cloud-top temperature” and “infra- taken into account. red emissivity” for the period 1989–2003 across In the EU projects CLOUDMAp and CLOUD- Europe (34-72 N, 11 W-32 E) with a spatial MAp2, the derivation of various cloud variables The 28 stations of the Swiss National Basic resolution of approximately 1 km, derived from from satellite data was studied in detail, and Climatological Network (NBCN) where visual the NOAA/AVHRR data and evaluated climato- the value of data assimilation was tested observations of clouds are carried out. logically. Globally, the results of the Internatio- for regional numerical weather prediction nal Satellite Cloud Climatology project (ISCCp) models. represent the most comprehensive cloud cli-

Resources required The funding of visual observations at the NBCN resources are required for systematic analysis stations is assured; in individual cases, the con- of the satellite data on cloud variables and the tinuation of observations could be threatened radiation balance for Switzerland. data are yet available for Switzerland ( 4.1 by staffing problems. Additional financial GEBA). 23

http://www.meteoswiss.admin.ch/web/en/services/data_portal/monitoring_networks.html

Klima_S22_23_Wolken.indd 23 5.3.2008 11:35:58 Uhr 2.7 Water vapour As well as surface measurements, vertical profiles of key atmospheric variables (air temperature, air pressure, wind, water vapour) are of crucial importance for climate monitoring. They make it possible to investigate climate signals in various layers of the atmosphere. As a natural greenhouse gas, water vapour is of particular interest in this context.

20hPa

50hPa

100hPa

200hPa

300hPa

pressure level [hPa] 500hPa

700hPa

925hPa

1970 1980 1990 2000 temperature geopotential height

Measurements in Switzerland Since 1942, Switzerland has a permanent Since 2000, a wind profiler installed at Payerne § Legal basis aerological station at Payerne, which is op- has continuously recorded vertical wind con- Under the Federal Act on Meteorology and erated by MeteoSwiss. Operations involving ditions up to an altitude of approx. 5km. This Climatology (MetG, SR 429.1), the federal two soundings per day were commenced in system is part of the European Wind Profiler authorities are required to record meteoro- 1954. Today, with four radiosondes launched Network (CWINDE). For continuous record- logical and climatological data continuous- per day, there are twice-daily continuous meas- ing of the vertical distribution of temperature ly throughout the territory of Switzerland. urements of air pressure, temperature, relative and water vapour, other passive and active They are also to participate in the record- humidity and wind speed/direction, and twice- remote sensing systems (microwave radio- ing, exchange and analysis of international daily measurements of wind speed/direction meter, lidar) are currently being tested for sub- meteorological and climatological data. In alone, up to an altitude of approx. 33km. An sequent installation on an operational basis. In addition, they are responsible for the pro- exception is humidity, which is measured up future, these remote-sensing data can also be vision of climatological information and for to an altitude of approx. 12 km. In addition, used for climatological analyses. the implementation of measures contribut- ozone soundings ( 2.8 Ozone) are carried out At the Institute of Applied Physics (IAP) of the ing to the long-term preservation of an intact three times per week. From 1999, for control University of Bern, a competence centre is environment. Under the Federal Ordinance purposes and to provide additional humidity concerned with research on water vapour in on Meteorology and Climatology (MetV, SR profiles, parallel soundings were performed the atmosphere. For this purpose, a new ob- 429.11), the Federal Office of Meteorology experimentally using a chilled-mirror, dew/ servatory was built in Zimmerwald near Bern in and Climatology MeteoSwiss is responsible frost-point hygrometer (“SnowWhite”). Since 2006. Here, microwave radiometers, GPS re- for these tasks. 2001, these have been carried out about once ceivers and spectrophotometers are used. a month. Measurements of wind, temperature and, in 24

Klima_S24_25_Wasserdampf.indd 24 5.3.2008 11:45:38 Uhr Klima_S24_25_Wasserdampf.indd 25 Payerne Payerne radiosounding 1967 −2006 microwave spectrum. and humidity profiles from the infrared and/or temperature retrieve to used be can satellites on installed sounders addition, In gramme. ( Reporting Data Meteorological Aircraft the under aircraft commercial most on out carried also are humidity cases, some andZimmerwald. Bern blue: Payerne; Red: measurements. upper-air out carrying Stations pressure level [hPa] Temperature andgeopotentialheightateightpressure levels 925hPa 700hPa 500hPa 300hPa 200hPa 100hPa 50hPa 20hPa temperature 1970 AMDAR 1980 geopotential height ) pro- ) The University of Bern holds a globally unique globally a holds Bern of University The soundings perday). 1954(two and day) per sounding 1948(one from possible is data of Analysis atmosphere. the in conditions vertical describing for tion Long timeseriesandtheirimportance quality requirements for long-term monitor- long-term for requirements quality ( Network Air Upper logical stations worldwide are part of the ( Network logical Climato- Basic Regional the of one is Payerne integration International under operationally files in the stratosphere have been determined tent since 1994. Since 2003, water vapour pro- con- vapour water integrated on series data of operation addition, In MeteoSwiss. of date to be regarded as assured under the legal man- Operation of the Payerne aerological station is Resources required the as struments GUAN selected operate to planned is it addition, to belong also will station Payerne the 12008, January From climate. the of ing series of Payerne provides a valuable founda- valuable a provides Payerne of series The long and high-quality radio sounding time basis to the monthly and daily a on soundings from data http://www.meteoswiss.ch/web/en/services/data_portal/monitoring_networks.html 1990 ttos ih bodr ag o in- of range broader a with stations WMO RBCN . About 150 of the 800 aero- GCOS GAW GUAN 2000 ) stations that transmit that stations ) Reference Upper Air Upper Reference and ), meeting higher meeting ), NDACC GUAN (Net- GCOS . In . in the troposphere. They complete the trend results long-term cooling in the stratosphere, and warming show These (2007). Haimberger and (2006) Häberli in found be to are soundings Payerne the of tions Homogeniza- 1996). al., et (Aschwanden line) tical time series shown are homogeneous from 1992 (ver- The 26 and m 500m. 800 between altitudes at levels pressure 8 for units without presented are means multiyear the from deviations relative smoothed ning of ozone balloon soundings ( begin- the with coincides period evaluation the of start The (1967–2006). Payerne at soundings night mid- from heights geopotential Temperaturesand for more than60years. tion system to have monitored the free atmosphere observa- only the is network radiosonde global The observations. satellite-based resultsof the with ent consist- are and measurements surface Swiss from s potential a as ae vial i a eiae database dedicated ( a in available made are Switzerland across from measurements Watervapour programmes. Change) position Com- Atmospheric of Detection the for work medium termthrough project funding. the in assured is instruments remote-sensing ( Network stations. swisstopo the at operationally 2006 the under basis experimental an on 1999) (from initially of analysis by estimated package. Total water vapour content has been 70 research stations. than more from measurements with dataset of the ( ( Center Data Climatic al ter ( ( Reading GUAN ed Global Radiosonde Archive of the Nation- the of Archive Radiosonde Global ed ai sudns r tasitd o the to transmitted are soundings radio STARTWAVE US ). The stratospheric water vapour profiles vapour water stratospheric The ). UK Monitoring Centres at the at Centres Monitoring IAP ). The data are archived at the Integrat- UK are integrated in the global GRUAN COST-716 ) and the Hadley Centre in Exe- in Centre Hadley the and ) ) as part of an GRUAN . aen hs en listed been has Payerne ). programme, and since and programme, station. The Payerne Payerne The station. NCDC NCCR GPS ai signals, radio 2.8 Ozone). The Climate work ) in Asheville in ) ECMWF NDACC AGNES in

5.3.2008 11:45:42 Uhr

25 ATMOSPHERIC OBSERVATIONS 2.8 Ozone The ozone layer in the stratosphere filters out a large proportion of the sun’s harmful ultraviolet rays. Monitoring of stratospheric ozone is therefore extremely important, especially in view of the rate of ozone depletion – which has however been reduced in recent years thanks to international agreements.

360 B156B156 MittelwerteMean value 1926 1926–1969: − 1969: Brewer ~330 Dobson units Brewer B72B72 B40

340

320

ozone column [DU] AbnahmeDecrease 19701970 – − 2006: 2006: ~20 Dobson units n 300

D101 D15 D7 D51D51 280 D2 D62D62

280 300 320 340 360 DobsonDobson

19251925 19501950 19751975 20002000

Measurements in Switzerland MeteoSwiss uses a variety of instruments to soundings are carried out three times a week, § Legal basis monitor ozone concentrations in the atmo- using an ozone sonde attached to an aerologi- Since 1985, thinning of the ozone layer by sphere over Switzerland. cal balloon ( 2.7 Water vapour). ozone-depleting substances such as chlo- At the Light Climatic Observatory (LKO) in Aro- Since November 1994, the Institute of Applied rofluorocarbons has been closely monitored sa, total ozone has been measured continuous- Physics (IAP) at the University of Bern has oper- under the Vienna Convention for the Pro- ly since 1926 using Dobson and Brewer spec- ated a Ground-Based Millimeter Wave Ozone tection of the Ozone Layer (Vienna Conven- trophotometers. These instruments measure Spectrometer (GROMOS) to measure strato- tion, SR 0.814.02) and the Montreal Protocol the transparency of the atmosphere to solar ul- spheric and mesospheric ozone at altitudes (SR 0.814.021). Worldwide, ozone meas- traviolet radiation at various wavelengths. This ranging from 20 to 70km. A second-gener- urements are coordinated by the Global At- is used to calculate the total amount of ozone ation instrument – the Stratospheric Ozone mosphere Watch (GAW) programme of the in the air column over Arosa. In addition, ozone Monitoring Radiometer (SOMORA) – has been World Meteorological Organization (WMO). profiles are derived using various methods of used operationally at Payerne by MeteoSwiss Switzerland is a member of the WMO (SR measurement and analysis. At Arosa, the Um- since 2002. 0.429.01) and participates in the GAW pro- kehr method (based on Dobson spectropho- Satellite measurements play an important role gramme in accordance with the Federal tometry) has been used since 1956 to obtain a in recording the global distribution of total Council Decree of 25 November 1994. As rough ozone profile (6–9 vertical layers). ozone. For the application of satellite-based the lead agency vis-à-vis the WMO, the Fed- At Payerne, radio soundings have been used data in Switzerland, good spatial resolution is eral Office of Meteorology and Climatology since 1968 to record ozone profiles directly with crucial. For example, the total ozone product, MeteoSwiss is responsible for Switzerland’s a high vertical resolution (approx. 50m) up to derived from Ozone Monitoring Instrument contribution to the GAW programme. an altitude of about 33km. For this purpose, (OMI) data, offers a horizontal resolution of 26

Klima_S26_29_Ozon.indd 26 5.3.2008 12:04:27 Uhr Total ozone Long time series and their importance Switzerland has a long history of ozone mon- 1980s, a second type of instrument (Brewer) itoring, going back to the first measurements was developed in Canada. MeteoSwiss used at Arosa in 1926. Total ozone over Arosa has its first Brewer device (B40) at Arosa in 1988. been determined on every sunny day virtual- In subsequent years, two more Brewer instru- ly without interruption down to the present. ments were installed. Total ozone over Arosa is Almost from the beginning of the time series, currently measured by two Dobson and three measurements have been carried out using the Brewer spectrophotometers. same type of instrument (Dobson). The global To date, the global networks of Dobson and network for monitoring of the ozone layer is Brewer instruments have maintained inde- largely based on Dobson instruments. In the pendent calibration procedures. The former is

Total ozone Arosa 1926 − 2006 Annual means in Dobson units (DU)

Dobson spectrophotometers have been used to meas- S 360 B156B156 MittelwerteMean value 1926 1926–1969: − 1969: on Brewer ure total ozone at Arosa for 80 years. The time series ~330 Dobson units Brewer B72B72 are mainly based on the three Dobson models D2, D15 ATI B40

and D101, and also on the redundant devices D7 and erv

340 D62. The homogenized time series shown here was BS carefully derived using data from the various Dobson o IC instruments (Staehelin et al., 1998; Zanis et al., 2006; er H

MeteoSwiss, 2007). While the Dobson spectrophotome- p S

320 ter still has to be operated manually, the Brewer device o is fully automated (Komhyr, 1980). This is the world’s ATM longest time series based on Dobson instruments. It ozone column [DU] AbnahmeDecrease 19701970 – − 2006: 2006: ~20 Dobson units n makes it possible to study the state of the ozone lay- 300 er before and after the beginning of anthropogenic influences, as well as interactions between ozone and D101 D15 the climate. D7 D51D51 280 D2 D62D62

280 300 320 340 360 DobsonDobson

19251925 19501950 19751975 20002000

based on the US reference instrument D083 and the latter on the reference triad in Toronto. Both networks produce almost identical results, with minor differences (1–3 %) depending on the season and latitude. These differences remain a subject of current research, and the 20- year parallel measurements carried out with Total ozone measurements and ozone profiles. Dobson and Brewer instruments at Arosa are Operational activities at Payerne and Arosa run of great importance in this regard. by MeteoSwiss (red) and research activities at the University of Bern (blue).

13 x 24 km. Swiss ozone monitoring data (Dobson/Brewer at Arosa, radio soundings at payerne, microwave radiometry at payerne and Bern) can make a decisive contribution to the validation of satellite-based data. 27

http://www.meteoswiss.ch/web/en/climate/global_climate_monitoring/GAW_CH_Allg.html

Klima_S26_29_Ozon.indd 27 12.3.2008 16:00:24 Uhr Ozone profile 0 – 33km Long time series and their importance Information on the vertical distribution of ozone tween approx. 5 and 50km. In addition, highly is important since the processes of ozone pro- complex mathematical processing is required. duction and destruction differ markedly in the For this reason, measurements could not be troposphere and the stratosphere. The first es- carried out on an operational basis until the timates of the ozone profile were obtained by 1950s. At Arosa, the Umkehr ozone profile se- means of special Dobson measurements in the ries was initiated with the Dobson D15 instru- 1930s. However, this so-called Umkehr method, ment. In 1980, the automated D51 instrument which has to be performed as the sun rises or came into operation. sets, is very elaborate. This method of measure- The Arosa Umkehr measurement series is the ment yields only 6–9 layers, at altitudes be- world’s longest and at the same time one of the

Ozone soundings Payerne 1967 − 2006 Monthly ozone concentrations at three pressure levels

200 Time series of monthly ozone concentrations 0.1 65 at various pressure levels for the period 1967– 0.20.2 60 22km 2006, measured by ozone balloon soundings (Jeannet et al., 2007). A similar series based on 0.50.5 53 150 Umkehr measurements at Arosa extends as far back as 1956, and series generated by the new 11 48 88 microwave radiometry technology at Bern and 22 4242 Payerne go back to 1995. The complementarity 100 66 of these various series is unique, allowing vital 5 3636 cross-comparisons to be made so as to assure the altitude [km] 29km best possible quality for long time series, includ- air pressure [hPa] 1010 3131 44

ozone concentration [nbar] 50 ing satellite-based measurements. Accordingly, 20 26 VMR [ppm] the Swiss ozone series mentioned are often used 22 3km in scientific publications worldwide, e.g. the Scientific Assessment of Ozone Depletion 50 21 0 reports published every four years by the WMO/ 100 16 95 9600 97 98 99 00 01 1970 1980 1990 2000 UNEP. 95 96 97 98 99 00 01 02 03 04 05 06 07 ppm]

few sources of information on vertical ozone ozone sondes. Measurements were first per- distribution in the years 1955–1970, before the formed for two years at Thalwil (1966/67), and start of satellite observations. Since 1988, the since 1968 the ozone sondes have been com- fully automatic Brewer B40 instrument has sim- bined three times a week (Monday, Wednes- ilarly produced Umkehr ozone profiles. Major day, Friday) with the meteorological radio- efforts are currently under way to homogenize sonde balloon activity at Payerne. The ozone these multiyear parallel measurement series. profiles obtained exhibit a high vertical resolu- In the late 1960s, ozone profiles were also de- tion (currently about 50m) between the Earth’s termined in situ for the first time using small surface and an altitude of 30–35km.

Klima_S26_29_Ozon.indd 28 12.3.2008 16:00:41 Uhr Ozone profile 20 – 70km Long time series and their importance In the early 1990s, a microwave radiometer ment at Bern from January 2000, and it has known as the Ground-Based Millimeter Wave been used operationally by MeteoSwiss at Pay- Ozone Spectrometer (GROMOS) was devel- erne since 2002. Covering an altitude range oped at the Bern University Institute of Applied of 20–70km and with a high temporal res- Physics (IAP). Since 1994, it has been used to olution, this time series extending over more determine the ozone profile about every 30 than 10 years augments the sounding data, as minutes. The second-generation Stratospher- it also permits conclusions concerning the bal- ic Ozone Monitoring Radiometer (SOMORA) loon burst height and short-lived processes in was tested in parallel to the GROMOS instru- the stratosphere.

Ozone profile microwave radiometry 1995 − 2007 Homogenized time series from Bern and Payerne

0.1 65 Homogenized time series of ozone

0.20.2 60 profiles determined by microwave radiometry at Bern and Payerne under an NDACC (Network for the 0.50.5 53 Detection of Atmospheric Composi- 11 48 88 tion Change) programme. The volume mixing ratio (VMR) of the trace 22 4242 gas ozone reaches its peak at an 66 altitude of around 35km during the 5 3636 summer season, with values of altitude [km] e ric obs rvations atmosph

air pressure [hPa] 1010 3131 44 approx. 8 parts per million (ppm). The ozone profiles also vary on dai- 20 26 VMR [ppm] ly to monthly timescales as a result 22 of atmospheric transport processes. 50 21 The annual cycle is clearly apparent in the distribution. 100 16 95 9600 97 98 99 00 01 95 96 97 98 99 00 01 02 03 04 05 06 07 ppm]

International integration Measurements from Arosa (Dobson and Brew- grated into models for use in the Integrated er) and Payerne (ozone soundings) are routine- Global Atmospheric Chemistry Observation ly supplied to the World Ozone and UV Radia- (IGACO) Strategy of the GAW programme. tion Data Center (WOUDC) in Toronto. These Under the joint EU/ESA environmental moni- data together with data from the two micro- toring initiative – Global Monitoring for Envi- wave radiometers (GROMOS and SOMORA) ronment and Security (GMES) – global and re- are also fed into the NDACC. All the time se- gional ozone maps are generated daily by the ries described above will be of major impor- ESA on a pre-operational basis in the GMES tance for future ozone monitoring. Interna- Service Element PROMOTE (PROtocol MOni- tionally, the in situ and satellite-based ozone Toring for the GMES Service Element on At- measurements are increasingly being inte- mospheric Composition).

Resources required Ozone monitoring operations at Payerne and pation in the WMO Global Atmosphere Watch Arosa are assured under the legal mandate of (GAW) programme. MeteoSwiss and through Switzerland’s partici-

http://www.iapmw.unibe.ch/

Klima_S26_29_Ozon.indd 29 5.3.2008 12:04:32 Uhr 2.9 Carbon dioxide Anthropogenic greenhouse gases are the main cause of global warming. Concentrations of greenhouse gases in the atmosphere have risen markedly since the industrial revolution. Levels of car-

bon dioxide CO2 – the most important greenhouse gas apart from water vapour – are now at least 35% higher than in the pre- industrial era.

395

390

385

380

375 concentration [ppm] 2 370 CO

365

360

2001 2002 2003 2004 2005 2006 2007

Measurements in Switzerland

The CO2 Act is concerned solely with CO2 total consumption of each fuel by the relevant § Legal basis emissions arising from fossil-based energy emission factor. Of relevance to Swiss climate policy at the consumption. CO2 emissions from these In Switzerland, atmospheric concentrations of

national level are the emission targets spe- sources are to be reduced in Switzerland CO2 have been measured by the Bern Univer- cified in the Federal Act on the Reduction of by 10 % by 2010, compared with 1990 sity Physics Institute on the Jungfraujoch since

CO2 Emissions (CO2 Act; SR 641.71). Of cen- levels. In this country, fossil fuels account for the end of 2000 and in Bern since October tral importance at the international level are almost 80% of total emissions of green- 2003. At the Jungfraujoch site, air samples are the emission targets of the Kyoto Protocol house gases, as defined in the Kyoto Pro- collected in 1 litre glass flasks each morning (SR 0.814.011), which is based on the United tocol, which underlines the significance of between 06:30 and 07:30. This guarantees

Nations Framework Convention on Climate the CO2 Act for compliance with the Kyoto measurement of carbon dioxide concentra- Change (Climate Convention, SR 0.814.01). requirements. tions in background air, avoiding contamina-

Under this national and international legis- In compiling the annual CO2 statistics under tion of samples with more heavily polluted

lation, Switzerland is required to compile the the CO2 Act and the National Greenhouse Gas lower layers of air through vertical advec-

latest statistics on greenhouse gas emissions Inventory under the Kyoto Protocol, emissions tion. In addition to measurements of the CO2 13 annually. The Federal Office for the Environ- are not measured directly, but determined part- mixing ratio, the C fraction and the OC2/NC2 ment (FOEN) is responsible for this task. ly on the basis of statistics on the consump- ratio of the samples is determined. The accu-

tion of heating and motor fuels (overall ener- racy of the CO2 measurements is better than gy statistics, Swiss Federal Office of Energy). ± 0.5 parts per million (ppm).

The CO2 emissions arising from the burning The Jungfraujoch and Bern stations are also of fossil fuels are calculated by multiplying the of global importance. Despite the existence 30

Klima_S30_31_Kohlendioxid.indd 30 6.3.2008 14:29:11 Uhr Klima_S30_31_Kohlendioxid.indd 31 world, additional, particularly continental, sta- ments overEurope. a lack of concurrent atmospheric O is thereFurthermore, fluxes. carbon terrestrial in uncertainties reduce to required are tions of various CO stations. the JungfraujochandBern Carbon dioxide measurements in Switzerland at Concentration inpartspermillion(ppm) Carbon dioxideatJungfraujoch2000−2007

CO2 concentration [ppm] 360 365 370 375 380 385 390 395 0120 0320 0520 2007 2006 2005 2004 2003 2002 2001 2 monitoring stations around the 2 measure- emissions are absorbed by the oceans and ter- trial biosphere and the oceans. Around half of terres- the by uptake and emissions between balance the by determined is atmosphere the changes in land use. The mixing ratio of CO and fuels fossil of burning fromthe emissions anthropogenic in rise the of result a is levels dioxide carbon atmospheric in increase The Long timeseriesandtheirimportance was one of the six ground-level flask air sam- air flask ground-level six the of one was the In intensified. AEROCARB being is and been has Europe in dioxide carbon of monitoring IP, ( Balance Carbon the of Observations Regional the Under integration International varia- temporal their and sinks terrestrial and ocean of calculation The ecosystems. restrial 2008 through the through 2008 until assured is station Jungfraujoch the at measurements dioxide carbon of funding The Resources required pling sites where combined precision measure- AEROCARB http://www.climate.unibe.ch/~mcl project, the Jungfraujoch station Jungfraujoch the project, ), CarboEurope and CarboEurope- EU rjcs ibre European Airborne projects EU project CarboEurope-IP.project 2 in tance for impor-major of thus are 2000 in station joch O O be determined by combined measurements of can oceans the and biosphere terrestrial the CO of and sink carbon a as biosphere the of ing bility is important for an improved understand- guaranteed bySwiss Subsequently, long-term monitoring should be sampling sites. flask 24 the of one and 12sites ground-level profiles. The Jungfraujoch station is one of the monitoring, flask sampling and vertical aircraft ground-level monitoring, continuous tall tower continuous involves network CarboEurope-IP ments of CO 2 2 (or O (or esrmns ntae a te Jungfrau- the at initiated measurements 2 uptake by oceans. Carbon absorption by absorption Carbon oceans. by uptake 2 /N GCOS clearly in excess of 2 ppm per year.per ppm 2 of excess in clearly this period, the rate of increase was Over 2008). al., et Valentino 2005; al., et (Sturm (2003–2006) years trend (red curve) over the past three CO positive amplified an suggests stations other with comparison A curve). (green ppm 11 be to found was variation Seasonal Jungfraujoch station. the at measured concentrations dioxide Carbon water vapour. from apart gas greenhouse tant impor- most the is dioxide Carbon 2 2 ) and CO and ) and O . 2 /N GCOS 2 . The series of CO of series The . 2 were carried out. The funding. 2 and 2

5.3.2008 13:23:48 Uhr

31 ATmOSPhERIC OBSERvATIONS 2.10 Greenhouse gases Apart from carbon dioxide, also methane, nitrous oxide and various synthetic gases contribute to the greenhouse effect. Concentrations of these gases are also steadily rising, further intensifying global warming. Long-term monitoring of greenhouse gases is therefore of major importance under international and national climate change legislation.

150 HFC-134a HCFC-141b CH3CCI3CH3CCl3

100

concentration [ppt] 50

0 2000 2001 2002 2003 2004 2005 2006

Measurements in Switzerland Since February 2005, atmospheric concentra- models, the measurements can be used to es- Legal basis tions of the greenhouse gases methane (CH ), timate Swiss and European emissions of these § 2 The Kyoto Protocol (SR 0.814.011), which nitrous oxide (N2O) and sulphur hexafluoride substances. This provides independent verifi-

is based on the Climate Convention (SR (SF6) have been measured by Empa and the cation of the emission estimates calculated by

0.814.01), covers not only CO2 but also Federal Office for the Environment (FOEN) at individual countries under the Kyoto Protocol.

methane (CH2), nitrous oxide (N2O) and the Jungfraujoch station, which is part of the Other greenhouse gases measured at the Jung- three synthetic gases – hydrofluorocarbons National Air Pollution Monitoring Network fraujoch station are the fluorinated chlorinat- (HFCs), perfluorocarbons (PFCs) and sulphur (NABEL). In addition, since 2000, Empa and the ed hydrocarbons (CFCs, HCFCs) responsible for

hexafluoride (SF6). Under the Kyoto Protocol, FOEN have also measured halogenated green- the depletion of stratospheric ozone. Here, the Switzerland has to reduce emissions of the house gases such as hydrofluorocarbons (HFCs) measurements can be used to identify any re- six greenhouse gases by 8%, compared with and perfluorocarbons (PFCs) at the Jungfrau- maining diffuse emissions of these substances 1990 levels, by 2008–2012 (1st commitment joch station as part of the System for Obser- prohibited under the Montreal Protocol. The period). The Montreal Protocol on Substances vation of Halogenated Greenhouse Gases in measurements carried out at the Jungfrau-

that Deplete the Ozone Layer (SR 0.814.021) Europe (SOGE). CO2 concentrations are also joch also make it possible to detect the use of is concerned with the ozone-depleting measured on the Jungfraujoch ( 2.9 Carbon these banned substances in Europe and iden- chlorofluorocarbons (CFCs) and their sub- dioxide). tify sources. stitutes (hydrochlorofluorocarbons HCFCs). These continuous measurements, as part of Halogenated greenhouse gases (CFCs, HCFCs, The handling of these substances is regu- a global monitoring system, make it possible HFCs) are also measured at Dübendorf in cam- lated by the Chemical Risk Reduction Ordi- to determine trends for these gases. At the paigns carried out at intervals of several years in nance (ChemRRV, SR 814.81). same time, in conjunction with meteorological order to track emission trends. Here, it is possi- 32

Klima_S32_33_Treibhausgase.indd 32 5.3.2008 13:33:03 Uhr Long time series and their importance Thanks to its high-altitude alpine location at future time series for GCOS. Likewise, the centre of the heavily industrialized Euro- measurements of the synthetic greenhouse pean continent and the low levels of local pol- gases have only been carried out operation- lution, the Jungfraujoch is particularly suita- ally at this site under the SOGE programme ble as a site for research on emissions of air since 2000, but they already provide an initial pollutants. Although measurements of green- signal reflecting international efforts to phase

house gases (CH4, N2O) were only initiated out ozone-depleting substances in compliance at the Jungfraujoch station at the beginning with the Montreal Protocol. of 2005, they represent extremely important

Greenhouse gases at Jungfraujoch 2000 − 2006 Concentration in parts per trillion (ppt )

150 Concentrations of three greenhouse HFC-134a gases on the Jungfraujoch since HCFC-141b measurements began in 2000. The decreased concentrations of trichlo- CH3CCI3CH3CCl3 roethane (CH3CCl3, black), a solvent OBSERVATIONS prohibited in the Montreal Protocol, 100 clearly indicates the success of the ban (Reimann et al., 2005). Emis- sions of the second-generation foam blowing agent HCFC-141b ATMOSPHERIC (orange), banned since 2003, are

concentration [ppt] 50 also declining (Derwent et al., 2007). At the same time, marked increases are now observable for replacement products, e.g. the refrigerant HFC- 134a (blue), which is a greenhouse gas (Reimann et al., 2004). 0 2000 2001 2002 2003 2004 2005 2006

International integration As a global GAW site, the Jungfraujoch sta- between the Jungfraujoch station and the tion plays an extremely important role in the renowned Advanced Global Atmospheric monitoring of atmospheric composition. All Gases Experiment (AGAGE) network. As GAW carbon dioxide and methane measure- measurements are based on the same calibra- ment stations are also part of GCOS. The data tion scale and a similar method, the results are are transmitted regularly to the World Data comparable and highly precise, with the same Centre for Greenhouse Gases (WDCGG) in temporal resolution. Stations where other greenhouse gases (apart Japan. In addition, there is close cooperation

from CO2) are measured. Red: Jungfraujoch global GAW station; blue: Dübendorf NABEL station.

Resources required Measurements of greenhouse gases at the are to be incorporated into the NABEL monitor- Jungfraujoch station are financed through ing programme ( 2.11 Air pollutants). ble to estimate emissions at a site close to the limited-term research projects. In future, they source and to compare the results with measurements from the Jungfraujoch station. 33

http://www.empa.ch/climate_gases

Klima_S32_33_Treibhausgase.indd 33 5.3.2008 13:33:06 Uhr 2.11 Air pollutants Trace gases with indirect effects on the climate (known as precur-

sor gases) – such as carbon monoxide (CO), nitrogen oxides (NOx) and volatile organic compounds (VOCs excluding methane) – only absorb infrared radiation to a limited extent, but they are chemi- cally active in the atmosphere. They thus promote the formation and prolong the lifetime of climate-relevant trace gases.

urbanStadt 140 ruralLand Prealps/JuraVoralpen/Jura highHochgebirge alpine

] 120 3

100

40 ozone concentration [µg/m

1990 1992 1994 1996 1998 2000 2002 2004 2006

Measurements in Switzerland The National Air Pollution Monitoring Network particle number, particle size distribution and § Legal basis (NABEL), a joint FOEN/Empa project, is an im- key constituents), as well as dust deposition Switzerland’s air pollution control policy is portant element of Swiss air pollution control, and constituents in precipitation. The meas- based on the Federal Act on Protection of forming the backbone for the monitoring of urement programme is continually adapted to the Environment (USG, SR 814.01), which impacts in Switzerland. The NABEL network meet new requirements and to include new requires the federal and cantonal authori- measures air pollution at 16 sites, representing variables. ties to monitor environmental impacts and key types of pollution situations: (a) city cen- The long-term, precise and internationally com- review the effectiveness of measures taken tre, heavy traffic (Bern, Lausanne), (b) city cen- parable time series make it possible to assess under this legislation. Under the Clean Air tre (Lugano, Zurich), (c) suburb (Basel-Binnin- air quality trends and to review the effective- Ordinance (LRV, SR 814.318.142.1), the gen, Dübendorf), (d) rural, nearby autobahn ness of air pollution control measures. The time Federal Office for the Environment (FOEN) (Härkingen, Sion), (e) rural, below 1000m a.s.l. series can be used to estimate the impacts of is responsible for determining the current (Lägeren, Magadino, Payerne, Tänikon), (f) gaseous air pollutants and aerosol particles on state and development of air pollution on rural, above 1000m a.s.l. (Chaumont, Davos, human health and the environment. NABEL a nationwide basis. Swiss air pollution con- Rigi-Seebodenalp), (g) alpine (Jungfraujoch). thus provides essential information for policy- trol policy thus complies with international The NABEL monitoring programme covers gas- makers. From the data collected, knowledge of

accords (Geneva Convention, SR 0.814.32) eous pollutants (ozone O3, nitrogen monoxide sources, sinks and atmospheric chemical pro-

and subsequent protocols. NO, nitrogen dioxide NO2, nitrogen oxides NOx, cesses can also be obtained.

sulphur dioxide SO2, carbon monoxide CO, In future, measurements of air pollutants from volatile organic compounds VOCs, ammonia satellite-based instruments (e.g. SCIAMACHY

NH3 ), particulate matter (PM10, PM2.5, PM1, onboard Envisat, OMI onboard Aura, GOME-2 34

Klima_S34_35_Luftfremdstoffe.indd 34 5.3.2008 13:43:45 Uhr Long time series and their importance In 1969, monitoring of air pollutants was initi- network was modernized and expanded from ated by Empa at three stations in Switzerland 8 to 16 stations. The longest ongoing time

(Dübendorf, Payerne, Locarno-Monti) under series is that for SO2 at Payerne (since 1969). a joint international programme involving 11 Other long series include those for suspended countries. In subsequent years, measurements particulates at the Dübendorf and Payerne sta-

were also performed at the Jungfraujoch stations (since 1973), and for SO2 and suspended tion. The NABEL network came into operation particulates at the high-altitude Jungfraujoch in stages from 1979. From 1989 to 1991, the station (since 1973).

Ground-level ozone in Switzerland 1990 – 2006 Concentrations in micrograms per m3 for various settings

urbanStadt Ozone is the third most important anthropogen- 140 ruralLand ic greenhouse gas. The figure shows how ozone Prealps/JuraVoralpen/Jura concentrations in the air have developed since highHochgebirge alpine 1990 (monthly means). For all four station types, ] 120 3 the median values as well as the lower quantiles OBSERVATIONS 100 increase over this period. In the urban areas, the increase is to be expected given the reduction in 80 nitrogen oxides. The rise in ozone concentrations at the rural and pre-Alpine stations suggests an 60 increase in background levels of ozone from an- ATMOSPHERIC thropogenic sources in the Northern hemisphere. 40 Peak hourly values at the heavily polluted sites ozone concentration [µg/m have decreased slightly since 1990. This trend is 20 most evident in the south of the Alps (Ordoñez et al., 2005, 2007; Brönnimann et al., 2002). 0

1990 1992 1994 1996 1998 2000 2002 2004 2006

International integration The NABEL network regularly exchanges network also supplies data to the European data with several international monitoring Air Quality Monitoring Network (EuroAirnet). programmes. Since the start of monitoring EuroAirnet was established by the Europe- operations, the rural Payerne and Rigi stations an Environment Agency (EEA) and includes have been part of the European Monitoring in particular stations in urban and suburban and Evaluation Programme (EMEP), which in- areas across Europe. Measurements from the vestigates in particular the long-range trans- NABEL stations are also used for air quality fore- NABEL stations. Red: NABEL stations participat- port of air pollutants across Europe. The casting and data assimilation purposes as part ing in the Global Atmosphere Watch (GAW) pro- NABEL measurements also contribute to the of the ESA PROMOTE project, a pilot project gramme and/or the European Monitoring and WMO Global Atmosphere Watch (GAW) pro- under the Global Monitoring for Environment Evaluation Programme (EMEP). gramme: the Jungfraujoch site is a global, and and Security (GMES) programme. the Rigi a regional GAW station. The NABEL

Resources required Funding of the NABEL network is assured for onboard Metop) will become increasingly im- the long term through contributions from the portant. The initial results of validation experi- FOEN and Empa. ments involving surface monitoring stations are highly promising. 35

http://www.bafu.admin.ch/luft/luftbelastung/index.html?lang=en http://www.empa.ch/nabel

Klima_S34_35_Luftfremdstoffe.indd 35 5.3.2008 13:43:49 Uhr 2.12 Aerosols Aerosols have direct and indirect effects on the atmosphere. The magnitude of these effects, as regards warming or cooling, remains one of the most significant sources of uncertainty in climate models. When inhaled, aerosols can have adverse effects on human health.

10-5 10−5 ] -1

10-6 10−6 scattering coefﬁcient [m

Jan96Jan96 Jan98Jan98 Jan00 Jan00 Jan02 Jan02 Jan04 Jan04 Jan06 Jan06

Measurements in Switzerland As part of Switzerland’s contribution to the AERONET programme, jointly established § Legal basis GAW programme, continuous aerosol measure- by NASA and the Centre National de la Re- Switzerland is a member of the World Me- ments are carried out by the Paul Scherrer cherche Scientifique (CNRS), currently coordi- teorological Organization (SR 0.429.01) Institute (PSI), on behalf of MeteoSwiss, at nates a network of approx. 400 ground-based and participates in the WMO Global Atmo- the High Altitude Research Station Jungfrau- aerosol remote sensing stations (using identi- sphere Watch (GAW) programme in accord- joch (HFSJ). The variables measured include the cal automatic photometers measuring in dif- ance with the Federal Council Decree of scattering, backscattering and extinction coef- ferent spectral ranges), operated by nation- 25 November 1994. As the lead agency vis-à- ficients at various wavelengths, together with al agencies, research institutes or universities. vis the WMO, the Federal Office of Meteorolo- the number concentration, mass concentration Two AERONET stations are located in Switzer- gy and Climatology MeteoSwiss is responsi- (TSP: total suspended particulates; PM10: par- land, at Lägeren (since 2003; run by the Uni- ble for the GAW programme in Switzerland. ticulate matter <10 μm, PM1: particulate mat- versity of Bern) and Davos (since 2005; run by Limits for anthropogenic aerosols are spec- ter <1μm) and size-resolved chemical com- the PMOD/WRC). The Federal Institute of Tech- ified in legislation concerning air pollutants position. In some cases (TSP, PM10), aerosol nology, Lausanne (EPFL), and the University of ( 2.11 Air pollutants). measurements at the Jungfraujoch site are car- Neuchâtel are involved in the ground-based ried out under the NABEL programme ( 2.11 aerosol monitoring activities of the European Air pollutants). In addition, at the 4 CHARM Aerosol Research Lidar Network (EARLINET). stations ( 2.5 Radiation) aerosol optical depth Valuable additional aerosol data (e.g. AOD) (AOD) is measured by spectrophotometers. are provided by passive satellite measure- A further category consists of the AErosol ments from AVHRR (onboard NOAA, Metop), RObotic NETwork (AERONET) stations. The SEVIRI (onboard Meteosat Second Generation), 36

Klima_S36_37_Aerosol.indd 36 5.3.2008 13:57:05 Uhr Long time series and their importance From 1973, TSP mass concentrations were toring was expanded to cover all other optical measured continuously at the Jungfraujoch variables and integrated into the GAW pro- station as part of the NABEL programme. In gramme. Chemical composition has been ad- 2006, this series was succeeded by measure- ditionally measured since 1998. Over the past ments of PM10 concentrations. two decades, emissions of anthropogenic aero- The PSI has carried out continuous measure- sols have declined in Europe as a result of im- ments of aerosol variables at the Jungfraujoch proved air pollution control measures. Current site since 1988. The first variable measured by observations, however, indicate a stabilization the PSI from the outset was the surface concen- or increase of particulate concentrations. tration of aerosol particles. In 1995, PSI moni-

Aerosol light scattering coefficient at Jungfraujoch 1995 – 2006 Scattering coefficient in m-1

The trend analysis shows that the greatest in- 10 -5 crease in the scattering coefficient (monthly −5 10 values, black) occurs between September and December (green), although the Jungfraujoch station is generally in the free troposphere dur- OBSERVATIONS

] ing this period. In contrast, during the summer -1 months from June to August (blue), measurements are strongly influenced by the planetary boundary layer. However, no statistically significant trend can be detected. The increase in the ATMOSPHERIC optical properties of aerosols observed in the 10 -6 −6 autumn may be associated either with the great- 10 er influence of boundary layer air masses or with scattering coefﬁcient [m long-range transport from areas with increasing air pollution (Collaud Coen et al., 2007).

Jan96Jan96 Jan98Jan98Jan00 Jan00Jan02 Jan02Jan04 Jan04Jan06 Jan06

International integration Since 2006, the Jungfraujoch site has been PSI aerosol monitoring programme at the Jung- one of the 25 global GAW stations worldwide. fraujoch site are the German Aerospace Cen- Aerosol measurements from the Jungfraujoch ter (DLR; aerosol absorption coefficient), NOAA, station are therefore regularly transmitted to Boulder (aerosol scattering coefficient) and the World Data Centre for Aerosols (WDCA) at TERA Environment (chemical analysis). In ad- the Joint Research Centre (JRC) in Ispra (Italy). dition, measurement campaigns are frequent- In addition, the data are supplied to the Chem- ly conducted at the station, especially to study The main aerosol monitoring stations. Red: ical Coordinating Centre of the European Mon- the interaction of aerosol particles with clouds. Jungfraujoch (GAW, CHARM); blue: Lägeren itoring and Evaluation Programme (EMEP) at The monitoring and research activities are inte- (AERONET), Davos (AERONET, CHARM), Payerne the Norwegian Institute for Air Research (NILU) grated into various ongoing EU projects (e.g. (CHARM), Locarno-Monti (CHARM). in Lillestrom. Key international partners for the ACCENT, EUSAAR, GEOMON).

Resources required The funding of aerosol monitoring operations ments at the Lägeren site and in Davos are MERIS (onboard Envisat), MODIS and MISR ( on- at the Jungfraujoch site is assured through the funded by the University of Bern and the board Terra), as well as the latest active satellite Swiss GAW programme. AERONET measure- PMOD/WRC respectively. measurements from CALIPSO (lidar) and CLOUDSAT (cloud profiling radar). 37

http://www.meteoswiss.ch/web/en/climate/global_climate_monitoring/GAW_CH_Allg.html

Klima_S36_37_Aerosol.indd 37 5.3.2008 13:57:09 Uhr 2.13 Pollen Pollen release and dispersal are controlled by meteorological conditions such as temperature, sunshine duration, precipitation and wind. Changes in airborne pollen levels, which may affect the prevalence of allergies or indicate the spread of new allergenic plant species, can be detected in good time by monitoring.

1.6.1.6. startBlühbeginn of flowering endBlühende of flowering

15.5.15.5.

1.5.1.5.

15.4.15.4. date

1.4.1.4.

15.3.15.3.

1.3.1.3.

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Measurements in Switzerland From the late 1960s, airborne pollen was an- automate counting with the aid of optical pro- § Legal basis alysed at individual stations in Switzerland on cesses and to make data available in nearly Under the Federal Act on Meteorology and a private basis. From 1982, pollen counts in real time. Climatology (MetG, SR 429.1), the federal Switzerland were coordinated by the Working Of the numerous types of pollen found in the authorities are required to record meteoro- Group on Aerobiology. Since 1993, MeteoSwiss air, only a small number are responsible for logical and climatological data continuous- assumes responsibility for operating the Na- the majority of pollen allergies. From spring to ly throughout the territory of Switzerland. tional Pollen Monitoring Network (NAPOL). summer in Switzerland, the pollen types in They are also responsible for the imple- This network comprises a total of 14 stations, question are from the following six plants: mentation of measures contributing to the covering the country’s major climate and hazel, alder, birch and ash in the spring, grass long-term preservation of an intact environ- vegetation regions. Most of the stations are in the early summer and summer, and mugwort ment. Pollen counts are made available by located near built-up areas and operate dur- in the late summer. These have recently been the responsible agency, the Federal Office of ing the vegetation period each year, from 1 Jan- joined by ragweed pollen, increasing levels of Meteorology and Climatology MeteoSwiss. uary to 30 September. Each measuring sta- which were detected at an early stage thanks As a preventive measure, the Federal Office tion is equipped with a volumetric pollen trap, to the NAPOL network. The most important of Public Health also provides information on which sucks in air. Each week, the pollen types type is pollen from grass, which can cause the spread of ragweed (Ambrosia artemisiifo- are identified under the microscope at the serious symptoms in more than 12% of the lia). The Federal Office of Agriculture (FOAG) MeteoSwiss laboratories (Payerne, Zurich), population in May and June. Pollen counts and the Federal Office for the Environment and daily pollen counts are determined, ex- vary according to the time of day and meteo- (FOEN) are both involved in efforts to control pressed as the number of pollen grains per rological conditions, and from one region to this highly allergenic plant. m3 air. Current research efforts are seeking to another. 38

Klima_S38_39_Pollen.indd 38 12.3.2008 16:01:09 Uhr Long time series and their importance Switzerland’s first pollen analyses were car- Coverage of the various climate and veg- ried out in basel in 1969. Since the 1980s, etation regions is provided by a selection of pollen counts have been determined at the measurements from the following NAPOL Neuchâtel, Davos and Lugano stations for the sites: basel (Northern foot of Jura Mountains), most important allergenic plants in Central Neuchâtel (Central Plateau), Davos (Alps) and Europe: hazel, alder, birch, ash, grasses, mug- Lugano (Southern Alps). The even distribution wort and the highly allergenic invasive species of these four representative sites is important ragweed. in Switzerland, these pollen types are so as to permit detection of future changes responsible for about 95% of pollen allergies. in pollen dispersal.

Birch pollen in Basel 1969 – 2006 Start and end of flowering

1.6.1.6. The beginning of the birch pollen season de- startBlühbeginn of flowering ONS

pends on temperature levels in February and i endBlühende of flowering

March. The higher the air temperature, the ear- AT v 15.5.15.5. lier the onset of birch flowering. Rising temper- SER

atures have brought forward birch flowering b O by a significant amount (13 days) since 1969. C 1.5.1.5. i Over the same period, the end of flowering has been brought forward by 14 days. Over the past 40 years, the length of the birch pollen season 15.4.15.4. date has remained unchanged; however, it has been ATMOSPHER brought forward by about two weeks (Clot, 1.4.1.4. 2003; Gehrig, 2004). Pollen grains are the main cause of allergies. The intensity and duration of the pollen season are highly dependent on 15.3. 15.3. environmental factors, with meteorological conditions being among the most important. The long time series are key indicators of the 1.3.1.3. effects of climate change on the main trigger 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 of allergies.

International integration As pollen dispersal is independent of nation- incorporating pollen count data for 170 pol- al borders, it calls for international data ex- len types from 557 stations across Europe, it changes. To this end, the European Aeroaller- is available for research purposes. This collec- gen Network (EAN) database was established tion of data provides valuable information on in 1988. The EAN pollen database now has 152 spatial and temporal trends in airborne pollen users from 48 countries including Switzerland. concentrations over Europe.

National Pollen Monitoring Network (NAPOL). The selection of 4 (red) of the 14 sites provides coverage of the various climate and vegetation regions.

Resources required The continuation of pollen monitoring is as- manual pollen counting methods. Renew- sured under the legal mandate of MeteoSwiss. al of the network will involve higher invest- Automation of the measurement network ment costs. is planned for the coming years, to replace

http://www.meteoswiss.ch/web/en/weather/health/pollen.html

Klima_S38_39_Pollen.indd 39 5.3.2008 14:04:58 Uhr 3.1River discharge Changes in climate affect the water cycle in various ways. In turn, possible shifts in hydrological variables, including lake and river water levels and discharge, have consequences for water management sectors such as water resource use, water protection and flood control.

120

20032003 100 19761976 19471947

80 /s] 3

60 discharge [m 40

0 Jan. Feb. Mar. Apr. May June July Aug. Sep.g. Oct. Nov. Dec. .

Measurements in Switzerland The Swiss river discharge monitoring networks mid-nineteenth century. It now comprises some § Legal basis currently consist of around 200 federal sta- 260 gauging stations on surface waters (rivers Under the Federal Water Protection Act tions, about 300 cantonal stations on smaller and lakes). In this network, 90% of all stations (GschG, SR 814.20), the federal authorities surface waters and a number of privately oper- have automatic remote retrieval facilities. are required to carry out surveys of national ated stations. The FOEN monitors water flows Under the NADUF programme, which is de- interest on hydrological conditions. The Fed- and – in cooperation with the Swiss Federal signed to assess the state of Swiss watercours- eral Office for the Environment (FOEN) is re- Institute of Aquatic Science and Technology es, concentrations of nutrients and pollutants sponsible for these tasks. (Eawag) and the Swiss Federal Institute for have been continuously measured at select- Forest, Snow and Landscape Research (WSL) – ed stations since the mid-1970s. Continuous water quality in Swiss waterbodies. Data col- sampling combined with discharge measure- lection takes the form of continuous measurements permits accurate calculations of sub- ments at permanent hydrometric stations and stance loads. individual measurements at temporary sites. In the 1950s, hydrological study areas (HUG) Surface water measurements fall into the fol- were first designated in Switzerland; over the lowing categories: the basic monitoring net- years, further catchment areas have been work, the National River Monitoring and Sur- added. The gauging stations in these areas are vey Programme (NADUF), water temperature part of the basic monitoring network. The aim and sediment transport. of the HUG studies is to observe long-term The basic monitoring network, which records changes in the water regime in near-natural water levels and discharge, goes back to the catchment areas across the country’s various 40

Klima_S40_41_Abfluss.indd 40 5.3.2008 14:35:33 Uhr Long time series and their importance In the Hydrological Yearbook of Switzerland, bellinzona, Inn-Martinsbruck), which record dis- data (including discharge) from all the gauging charge from Switzerland and, in some cases, stations operated by the FOEN has been pub- belong to the NADUF programme. The HUG lished since 1917. The longest continuous dai- gauging stations belonging to the basic mon- ly discharge series come from stations on the itoring network have an average time series Rhine (1891 basel), the Thur (1904 Andelfin- length of 40 years. The HUG areas were se- gen) and the birs (1917 Münchenstein). Among lected with a view to covering all types of hy- the oldest gauging stations are four border drological regime in Switzerland. stations (Rhine-basel, Rhône-Chancy, Ticino-

Thur discharge for 1947, 1976 and 2003 in Andelfingen Discharge rates averaged over 30 days, in m3/s

120 The precipitation periods of March and Novem- ber 1947, July 1976 and October 2003 are evident 20032003 from the discharge curves. Also clearly appar- ATIONS 100 19761976 v 1947 ent are the low-water periods of varying dura- 1947 SER

tion (FOEN, 2004). Fluctuations in discharge are b O indirectly influenced by meteorological varia- 80 bles and by the storage capacity of snow cover, /s] 3 glaciers, soils, groundwater and lakes. Discharge 60 data provide an important basis for the analysis

of runoff estimates generated by hydrological TERRESTRIAL

discharge [m modelling. A long-term change in the discharge 40 regime will have consequences for various aspects of water management.

0 Jan. Feb. Mar. Apr. May June July Aug. Sep.g. Oct. Nov. Dec. .

International integration A selection of stations (12) with long dis- Hydrology (GTN-H), which is supported by charge series participate in the Global Runoff GCOS, GTOS and the WMO Hydrology and Data Centre (GRDC). Daily river discharge data Water Resources programme. The European from a total of 27 Swiss stations is supplied to Terrestrial Network for River Discharge (ETN-R) the GRDC, representing an important contribu- is a GRDC contribution to the European Flood tion to international data exchange. The GRDC Alert System (EFAS), facilitating medium- to is part of the Global Terrestrial Network for long-term flood forecasts. The selection of Switzerland’s most important discharge series comprises various monitoring networks (red + blue), including border stations (blue).

Resources required It can be assumed that, given the existing legal servation programmes jointly supported by basis, measurements of discharge and conti- the FOEN, the Eawag and the WSL. These pro- climatic regions. They therefore cover run- nuous monitoring of surface waters will be grammes are fundamental to flood control off depth and area precipitation for about continued. In the medium term, funding is to and water protection efforts. 50 catchment areas. be regarded as assured for the long-term ob- 41

http://www.bafu.admin.ch/hydrologie/index.html?lang=en

Klima_S40_41_Abfluss.indd 41 5.3.2008 14:35:36 Uhr 3.2 Lakes Lakes may react sensitively to changes in climate, depending on the type and size of waterbody concerned. Among the effects are changes in the temperature of surface and deep waters, in the temporal dynamics of plankton and in the duration of ice cover. Historical records of freeze and thaw dates for lakes permit valuable inferences about past regional climatic conditions.

730 11 720

500 9

8 7 450 6 lake level [m a.s.I.] 5 4 3 2 400 1

1900 1920 1940 1960 1980 2000

Measurements in Switzerland The basic monitoring network operated by the tion of Lake Constance (IGKB). The lakes of § Legal basis FOEN Hydrology Division, comprising a total Canton Ticino are monitored by the Joint Com- The goals and requirements for the observa- of around 260 hydrometric stations, includes mission for the Protection of Italian-Swiss Wa- tion of lake variables are specified in the Fed- more than 30 stations on Swiss lakes. These ters (CIPAIS), and Lake Geneva by the Interna- eral Ordinance (GSchV, SR 814.201) accom- lake stations measure discharge, which de- tional Commission for the Protection of Lake panying the Water Protection Act (GSchG, pends directly on lake water levels. The verti- Geneva (CIPEL). SR 814.20). With regard to water tempera- cal and horizontal differences in temperature Lake water temperature profiles are deter- ture, one of the requirements specified for occurring in the lakes are not, however, record- mined, in some cases, from boats at a high res- standing waters is that natural temperature ed by the FOEN temperature monitoring net- olution, with the aid of probes. Temperatures regimes are not to be detrimentally altered work. Measurements of lake water tempera- are usually measured once or twice a month at as a result of human interventions. Other rel- tures are carried out as part of comprehensive various depths between the lake surface and evant provisions are to be found in the fed- water quality studies by cantonal water protec- bottom. Monthly measurements are required eral legislation on environmental protection tion agencies, international commissions and for an understanding of the development of (USG, SR 814.01), nature and cultural her- the Swiss Federal Institute of Aquatic Science lake temperatures over time. In addition, for itage protection (NHG, SR 451) and the ex- and Technology (Eawag). For example, Lakes larger lakes, water surface temperature can be ploitation of hydroelectric power (WRG, SR Murten, Neuchâtel and Biel are monitored in derived from satellite data. This is done oper- 721.80). a joint project by the competent authorities of ationally for various Swiss lakes using NOAA Cantons Bern, Fribourg and Neuchâtel. Mon- AVHRR data (at the University of Bern). itoring of Lake Constance is coordinated by the International Commission for the Protec- 42

Klima_S42_43_Seen.indd 42 5.3.2008 14:44:35 Uhr Long time series and their importance Water temperature is an important variable Measurements have been carried out at differ- for regional climate modelling. Monthly water ent temporal resolutions and at various depths temperatures have been recorded by the Zurich on Lake Zug (since 1950), Lake Greifen (since water utility at the Thalwil site on Lake Zurich, 1956), Lake Geneva (since 1957), Lake Neuchâ- with some interruptions, since 1936. Over this tel (since 1963), Lake Pfäffikon (since 1972), period, the number of depths per profile var- Lake Walenstadt (since 1972) and Lake Aegeri ies. Since 1977, weekly observations have been (since 1975). As the measurements in these se- made by the University of Zurich (Limnological ries have been carried out differently over the Station, Institute of Plant Biology) in the middle years, a degree of inconsistency both within of the lake between Küsnacht and Rüschlikon. and between the time series is inevitable.

Freezing of lakes on the Swiss Central Plateau 1901 – 2006 Data compiled for 11 lakes as a function of altitude above sea level

Data on ice cover for alpine lakes 730 11 720 contain relevant climatological information, since ice cover and win- 10 ter temperature are closely related. Cross: complete ice cover. Line: OBSERVATIONS years for which no data are avail- 500 9 able. Lakes: 1 = Untersee, 2 = Up- per Lake Zurich, 3 = Lake Murten, 4 = Lake Biel, 5 = Lake Greifen, 8 7 6 = Lake Hallwil, 7 = Lake Baldegg, TERRESTRIAL 450 6 8 = Lake Sarnen, 9 = Lake Sem- lake level [m a.s.I.] 5 pach, 10 = Lake Pfäffikon, 11 = Lake 4 3 Aegeri. From these data, ice cover can be shown to have declined 2 400 1 over the past 40 years. This trend is particularly marked for lakes that 1900 1920 1940 1960 1980 2000 freeze rarely (Hendricks Franssen and Scherrer, 2007).

International integration Historical records of freeze and thaw dates for the present. This dataset is unique for central lakes permit valuable inferences concerning the Europe. The freeze and thaw dates for alpine past regional climate and provide additional lakes are the only lake variables transmitted information on winter temperature patterns. to an international data repository. The Global These observations are not carried out system- Lake and River Ice Phenology Database at the atically across Switzerland and come from var- National Snow and Ice Data Center (NSIDC) in ious sources (including newspapers and per- Boulder, Colorado, archives observations from Water temperatures have been measured at vari- sonal records). The longest time series available Lakes St.Moritz, Silvaplana and Sils. Observa- ous sites since about the middle of the twentieth in Switzerland is for Lake St.Moritz; starting tions are no longer being updated for the two century (red). Freeze and thaw dates have been in 1832, it extends without interruption up to last-named lakes. observed for more than 100 years (blue).

Resources required Lake vertical temperature measurements are ly observed. As no legal basis exists for long- carried out by various institutions across Swit- term observations of this kind, these time se- zerland in an uncoordinated manner. Likewise, ries are not guaranteed. freeze and thaw dates are not systematical-

http://www.eawag.ch/organisation/abteilungen/wut/schwerpunkte/umweltisotope/

Klima_S42_43_Seen.indd 43 5.3.2008 14:44:42 Uhr 3.3 Groundwater More than 80% of Switzerland’s drinking and industrial water is sourced from groundwater. Groundwater recharge is influenced not only by precipitation and dry periods but also by human activities. Quantitative and qualitative monitoring of groundwater is therefore required nationwide to ensure the long-term preservation of these resources.

14 /s] 3 12

8 discharge [m 6

0 1 2 3 4 5 6 7 8 9 10 11 12 month monthly mean maximum 1959–2004 mean 1959–2004 minimum 1959–2004

Measurements in Switzerland The National Groundwater Observation Pro- natural and anthropogenic factors influencing § Legal basis gramme (NAQUA) operated by the FOEN is de- Switzerland’s groundwaters. Under the Federal Act on the Protection of signed to provide a representative picture, in NAQUA comprises four modules: TREND for Waters (GschG, SR 814.20), the federal au- both qualitative and quantitative terms, of the tracking long-term developments in ground- thorities are required to carry out surveys of state and development of Swiss groundwater water quality (50 stations), SPEZ for studies of national interest on hydrological conditions resources. It thus facilitates (a) the protection, specific pollutants (500 stations), QUANT for and on water quality in surface and ground- long-term preservation and sustainable use of observing groundwater quantity (100 stations), waters. The Federal Office for the Environ- natural groundwater resources and the elimi- and ISOT for observing isotopes in the water ment (FOEN) is responsible for these tasks. nation of existing damage and (b) the protec- cycle (23 stations) ( 3.5 Isotopes). tion of the public against excessive pollution Groundwater quality and quantity is also mon- (harmful organisms and substances). itored at numerous sites by various institutions NAQUA provides reliable information on (a) the (universities, water utilities, cantons). Altogeth- main types of aquifer relevant to groundwater er, groundwater levels and spring discharges use in Switzerland (karstic or fractured rocks are currently observed at around 900 stations. and unconsolidated sediments); (b) the main Measurements of groundwater levels are gen- aquifers used as sources of drinking water in erally carried out manually or automatically in a Switzerland; (c) aquifers in the various major perforated tube installed in the aquifer. Spring climatic and landscape regions of Switzerland, discharge is measured as close as possible to e.g. Jura, Central Plateau, Pre-Alps, Alps and the spring using a natural cross-section or with south of the Alps; and (d) the most important the aid of an artificial overflow. 44

Klima_S44_45_Grundwasser.indd 44 5.3.2008 14:55:18 Uhr Long time series and their importance To better assess the possible consequences of from water utility pumping wells. Since the climate change, NAQUA pursues an integrat- end of the 1970s, groundwater levels have ed approach, aimed at increasingly record- been continuously monitored nationwide, ing groundwater quality and quantity at the e.g. on the Rhine (Maienfeld, since 1975), Arve same stations over time. Under the NAQUA (Soral, since 1975) and vedeggio (lamone, since programme, the FOEN is therefore collabo- 1980). The discharge of the Areuse spring in rating closely with the cantons. The longest St-Sulpice has been measured continuously groundwater level data series in Switzerland since 1959, representing one of Switzerland’s (from around 1900 to the present) are available longest spring discharge time series.

Discharge of Areuse spring in St-Sulpice 1959 – 2004 Mean monthly discharge in m3/s

20 Mean monthly discharge of the Areuse spring in St-Sulpice for 18

the observation period 1959–2004. ATIONS v 16 These data contribute significantly SER

to our understanding of climate var- b

14 O

iability. Such fluctuations may differ l /s] 3 12 widely as a result of Switzerland’s small-scale diversity, but they are 10 not currently quantifiable. The im-

8 pacts of climate change on ground- TERRESTRIA discharge [m water can only be reliably estimat- 6 ed with sufficiently long time series 4 on groundwater quality and quantity (Schürch et al., 2006). 2

0 1 2 3 4 5 6 7 8 9 10 11 12 month monthly mean maximum 1959–2004 mean 1959–2004 minimum 1959–2004

International integration Groundwater observations are coordinated in- to the Global Terrestrial Network Hydrology ternationally by various networks. The Inter- (GTN-H). The data and information network national Groundwater Resources Assessment responsible at the European level is EUROWA- Centre (IGRAC), a joint UNESCO/WMO initia- TERNET, which is operated by the European tive for global information exchange, belongs Environment Agency (EEA).

Switzerland’s National Groundwater Observa- tion Programme NAQUA: selected stations from TREND (green) and QUANT (blue) modules, and stations belonging to both modules (red).

Resources required The operation of monitoring stations under the tation of springs, the technical and financial NAQUA programme can be regarded as as- resources required for station equipment and sured, at least in the medium term. However, data transmission have proved to be substan- especially in connection with the instrumen- tial in some cases.

http://www.bafu.admin.ch/hydrologie/index.html?lang=en

Klima_S44_45_Grundwasser.indd 45 5.3.2008 14:55:22 Uhr 3.4 Water use Water resource availability is essential for the provision of supplies to the public and for various economic sectors. With rising temperatures, longer dry periods and seasonal fluctuations, climate change affects water supplies and demand. A knowledge of water consumption is therefore of great importance.

4% drinking water 20% groundwater 9% lakes 5% rivers 10% channels 52% Suonen

Measurements in Switzerland The natural geography of the Alps makes Swit- gation. This is due to Switzerland’s federalist § Legal basis zerland a water-rich country. structures, which explain the lack of uniform Among the aims of the Federal Water Protec- In Switzerland, water consumption data are data. Quantitative values concerning irrigat- tion Act (GSchG, SR 814.20) are to ensure collected by different agencies to different ex- ed areas are determined with the aid of sur- economic use of drinking and process water tents and with varying degrees of regularity. veys conducted by the Swiss Farmers’ Union and to protect agricultural irrigation from ad- For example, data on the withdrawal, treat- and the Federal Office for Agriculture (FOAG). verse impacts. The legislation also includes ment and supply of drinking and process wa- In the spring of 2007, the FOAG carried out a provisions on residual flows, restricting water ter are collected by the Swiss Gas and Water survey on irrigation. Here, data were compiled withdrawals from surface waters. Conces- Industry Association (SVGW) and determined at the cantonal level, providing an updated es- sions or licenses granted by the cantonal by utilities that supply water to about 50% of timate of consumption compared with the pre- authorities are required where water is used the population. The main source of drinking vious survey (2002). for irrigation. In contrast, drinking water water in Switzerland is groundwater, which is Graubünden is the first canton to have devel- abstraction has priority in the exploitation accordingly of great importance and subject to oped a concept defining areas that require ir- of groundwater resources. The legal basis systematic qualitative and quantitative moni- rigation. This study was carried out with expert is provided by cantonal water management toring ( 3.3 Groundwater). support at the suggestion of the Graubünden legislation. Water consumption associated with Swiss agri- farmers’ union and was mainly funded by the culture is confined to relatively small areas and canton. According to the FOAG, a nationwide essentially to extremely dry areas and vegeta- study of irrigation water consumption has the ble farming. Scant information is available on backing of about half of all cantons. the distribution and extent of agricultural irri- 46

Klima_S46_47_Wassernutzung.indd 46 5.3.2008 15:04:52 Uhr Klima_S46_47_Wassernutzung.indd 47 liably. ties, making it impossible to determine areas re- uncertain- involve these estimates; on based is consumption water agricultural of extent The Cantonal estimatesfor2006 Irrigated areas ofSwitzerlandbysource ofwithdrawal 2 Suonen 52% channels 10% groundwater 20% %rivers 5% lakes 9% drinkingwater 4% Per capita water consumption is a standard in- two thirds of which is to be found in the can- the in found be to is which thirdsof two of 38,000 ha refers to regularly irrigated land, area total survey.The 2007 the in ha 38,000 and 2000 in ha 199530,000 in to ha 25,000 fromrose1990s.area irrigated estimated The early the since organizations international to transmitted and prepared been have use ter wa- agricultural of estimates Switzerland, In Long timeseriesandtheirimportance Resources required ( ticularly in developing and emerging countries par-use, water agricultural on system mation The tainability. O ternational environmental indicator used by the integration International a is there conditions, production in changes associated and change climate from arising water for demand growing the of view In

AQUASTAT e http://www.blw.admin.ch/themen/00010/00071/00230/index.html CD and FAO ). AQUASTAT in various studies to assess sus- FAO maintains a global infor- global a maintains is part of the Global which the global networks on river discharge river on networks global the which rigation technologies. which depends on cultivation methods and ir- use, water of efficiency the in differences al occasionally.region-irrigated major areThere regularly,rigated 12,000another is land of ha ir-areas the to addition In areas. irrigated on data precise lack to appear cantons other contrast, In Graubünden. and Valais of tons requirements. irrigation cantons’ the estimate to as so forts ef- collection data systematic for need clear Terrestrial ods andirrigationtechnologies. appropriateusing by case the meth- cultivation currently is than efficiently more met be could However,future. demand in increasewater bly The extent FOAG). of irrigated areas will proba- rigated area (personal communication, A. Schild, ir-total the of half about for account (Suonen) plied with water from traditional open channels Alpine dry valleys of Valais and Graubünden sup- Central the in Grasslands used. system of type the by and withdrawal, of source and crop of cies. Irrigated areas can be classified by the type on estimates from the majority of cantonal agen- arebased data consumption water Agricultural database isbasedon the to supplied agriculture Swiss in consumption water on information The ( (  GRDC 3.1 River discharge and ) and groundwater ( etwork for Hydrology ( Hydrology for network FOAG  IGRAC estimates. 3.3 Groundwater). ) also belong AQUASTAT GTn -H ), to ),

5.3.2008 15:04:55 Uhr

47 TeRReSTRIAl ObSeRVATIOnS 3.5 Isotopes Serving as natural tracers, isotopes of oxygen and hydrogen leave a “fingerprint” in numerous components of the climate system. Accordingly, in addition to their use in groundwater management and protection, long-term isotope data series provide necessary reference values for climatological studies.

- 7

- 8 Locarno - 9 Bern -10

-11 Meiringen -12

oxygen-18 [‰] Guttannen -13

-14

-15 Grimsel, Hospiz

-16 1970 1975 1980 1985 1990 1995 2000 2005

Measurements in Switzerland The signature left by isotopes in the water cy- tios of oxygen-18, deuterium and tritium in § Legal basis cle is mainly due to isotope fractionation during water are measured. The FOEN operates Under the Federal Act on the Protection of the formation of precipitation. Most naturally the ISOT network in cooperation with the Waters (GschG, SR 814.20), the federal au- occurring elements have stable isotopes; other Climate and Environmental Physics group at the thorities are required to carry out surveys of isotopes are radioactive (unstable) and decay University of Bern. The ISOT precipitation sta- national interest on hydrological conditions over time. The stable isotopes oxygen-18 (18O) tions are spread across the various climatic re- and on water quality in surface and ground- and deuterium (2H) and the radioactive hydro- gions of Switzerland. Monthly composite sam- waters. The Federal Office for the Environ- gen isotope tritium (3H) are constituents of the ples from a precipitation gauge emptied daily ment (FOEN) is responsible for these tasks. water molecule. They are measured by various are used for isotope measurement. Stations be- institutions at about 135 stations across Swit- longing to the discharge monitoring network zerland in water samples from precipitation, (basic monitoring network) or the National Riv- rivers, lakes, glaciers, snow and groundwater. er Monitoring and Survey Programme (NADUF) In 1992, as part of the National Groundwa- were selected as ISOT surface water stations. ter Observation Programme (NAQUA), a new At these sites, composite samples are collect- module was established for the observation of ed automatically each month or spot samples isotopes in the water cycle (ISOT). are taken manually. At the ISOT groundwater The ISOT network currently comprises 23 sites stations, spot samples are collected monthly distributed throughout Switzerland: 13 pre- for isotope analysis, and water temperature, cipitation, 7 surface water and 3 groundwa- electrical conductivity and spring discharge/ ter stations. At these stations, the isotope ra- groundwater levels are also determined. 48

Klima_S48_49_Isotope.indd 48 5.3.2008 15:15:25 Uhr Klima_S48_49_Isotope.indd 49

(blue) andingroundwater (green). (blue) waters surface in (red), precipitation in tium ures the ratios of oxygen-18, deuterium and tri- meas- (ISOT) network observation isotope The oxygen-18 [‰] Moving monthlyaveragesinpermilleatfive isotopeinprecipitation 1971Oxygen-18 –2003 -1 -1 -1 -1 -1 -1 -1 - - - 9 8 7 9017 9018 9019 002005 2000 1995 1990 1985 1980 1975 1970 6 5 4 3 2 1 0 Bern Grimsel, Hospiz Meiringen Locarno ISOT sites International integration International have been transmitted to the database of the of database the to transmitted been have gether form a to- and Switzerland in available longest the are sites five these from series ly 1970s.Time ear- the since analysis isotope for used been composites of daily precipitation samples have and Grimsel Guttannen, At the monitoring stations in Bern, Meiringen, Long timeseriesandtheirimportance tribution to internationally coordinated isotope ISOT ( Agency Energy ( Precipitation in Isotopes of Network Global Since to a.s.l.) (1950m Pass Grimsel the across a.s.l.) (541m Bern from Programme ( Programme Observation Groundwater National the into the of Operation Resources required GNIP http://www.bafu.admin.ch/hydrologie/index.html?lang=en Guttannen network thus makes an important con- important an makes thus network ) operated by the International Atomic International the by operated ) 1992 , data from selected from data , NAQUA NW/SE IAEA ISOT ). As the tritium content tritium the As ). profile through the Alps ad the and ) ocarno (379m a.s.l.). a.s.l.). (379m locarno stations is integrated is stations cro monthly locarno, ISOT WMO stations The . thus coverSwitzerland’s majorrivers. Scex and Inn at These S-chanf). measurements 1980s at (Rhine Diepoldsau, Rhône at Porte du mid- the to back dates rivers in observation Isotope measured. arehumidity, relative and where additional variables, such as temperature matological stations operated by MeteoSwiss, cli- to close located are stations the of Most reduced. continuously being is analyses tritium costly of number the declines, samples water of research forinternational programmes. e.g. This makes the time series, as compared with other countries. land has a dense monitoring network with long Switzer- Austria, and Germany Togetherwith as reference values or for calibration purposes. programmes, with data being used in research ditions prevailing during the for- the during prevailing ditions con- hydrometeorological the to due is cycle water the in topes iso- by left signature The rivers. fromSwiss large of discharge the apparent also is which decades, three past the over trend climate the reveal 1971–2003, cipitation, pre- in isotope oxygen-18 the of averages monthly moving The gartner, 2005). Wein- and (Spreafico point tion collec- the at rainfall final the to humidity of source original the from – precipitation of mation ISOT series particularly valuable, 5.3.2008 15:15:29 Uhr

49 TERRESTRIAl OBSERvATIONS 3.6 Snow cover As well as playing a key role in the climate system, snow cover is a vital economic factor in sectors such as tourism, water management, hydropower, agriculture and transport. With long time series for snow variables, conclusions can be drawn concerning past and future regional trends.

140 Engelberg, 1060 m a. s. l. Annual values 130 (Nov– Apr) 20-years weighted average 120 Mean (1891 – 1987) vs (1988 – 2007) 110 100 90 80 70 60 50 40 30

number of days with snow depth ≥ 30cm 20 10 0 19001890 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Measurements in Switzerland The most important observations for snow cli- stations have been supplemented by the ap- § Legal basis matology are snow depth, new snow depth, prox. 70 automatic stations of the Intercan- Under the Federal Act on Meteorology and and water equivalent of new and total snow tonal Measurement and Information System Climatology (MetG, SR 429.1), the federal cover. Snow depth and new snow depth are (IMIS), located at altitudes between 2000 and authorities are required to record meteoro- recorded by measurement networks operated 3000 m a.s.l. This network was established in logical and climatological data throughout by the SLF, MeteoSwiss and other cantonal and cooperation with the FOEN under an intercan- Switzerland and to provide weather hazard private institutions. tonal agreement. warnings. Under the Federal Ordinance on The SLF network comprises both automatic At the 10 mountain stations of the automa- Meteorology and Climatology (MetV, SR and conventional stations (measuring points tic ENET network, observations required for 429.11), the implementing agency is the Fed- MS and comparison stations VG). At the avalanche warnings are jointly carried out by eral Office of Meteorology and Climatology roughly 100 conventional stations, the varia- MeteoSwiss and the SLF. At about 75% of MeteoSwiss. Under the ETH Board Ordinance bles are measured manually by observers each the roughly 340 precipitation stations in the on Research Institutes of the ETH Domain day. Most of the stations are located at medium MeteoSwiss NIME network, daily measurements (SR 414.161), the Swiss Federal Institute for altitudes between 1000 and 2000m a.s.l. of total and new snow depth are carried out Snow and Avalanche Research (SLF), as part By contrast, the 39 automatic (ANETZ, now manually. Unlike at the conventional and auto- of the Swiss Federal Institute for Forest, Snow SwissMetNet) and 11 conventional (KLIMA) matic stations, these data are not recorded di- and Landscape Research (WSL), is responsi- snow measurement stations operated by gitally. Satellite data are being used operation- ble for issuing avalanche warnings and in- MeteoSwiss are evenly distributed across ally to determine snow cover, e.g. from NOAA formation on the development of snow and Switzerland, also covering altitudes below AVHRR (by the University of Bern) and Meteo- avalanche conditions in Switzerland. 1000m a.s.l. Since 1996, the SLF and MeteoSwiss sat Second Generation (by MeteoSwiss). 50

Klima_S50_53_Schneebedeckung.indd 50 5.3.2008 15:56:54 Uhr Klima_S50_53_Schneebedeckung.indd 51 snow depth (>100 years). snow depth(>100 time series for snow and years) depth new (>50 important most and longest the with Stations Days withsnowdepthofatleast30cmforthenovember- Snow coverinEngelberg1891 – 2007 number of days with snow depth ≥ 30cm 100 110 120 130 140 20 30 40 50 60 70 80 90 10 0 Nv Apr) (Nov– a. Engelberg, 1060s. m l. 19001890 1910 (Continued on page 52) (Continued 1920 1930 1940 1950 on of precipitation measurements ( measurementsprecipitation of on initiati- early the with associated be may this depth. snow new for than shorter are depth snow total for series measurement important 50 years). purposes (> climatological for long sufficiently are series time available the that is stations ventional con- the by offered advantage the networks, measurement automatic the with Compared Long timeseriesandtheirimportance Snow depth cipitation). cipitation).

Mean (1891 2007) – – 1987) vs(1988 20-year weightedaverage Annual values http://www.meteoswiss.admin.ch/web/en/services/data_portal/monitoring_networks.html http://www.slf.ch/research/snowtrends/snowtrends-en.html 1960 april period the longest total snow depth series 1970 1980 in most cases, the most 1990 2000  2.2 Pre- 2.2 2010 (e.g. Weissfluhjoch, (e.g. snow depth began at the earliest in the 1930s at most sites, continuous observations of total station. to station from and year to year from widely varied measurement of frequency the but 1900,around began also measurements (1896). Davos and (1890) go back to the 1890s – digitization iftheyare tobeusedinanalyses. and therefore require additional processing and are only available in the original analogue form beforecollected data the cases, many in 1930 measurement instructions from 1893 onwards. of introduction the following regularly less or Data on snow depth were only recorded more difficult tointerpret. at this altitude, time series from these sites are depth associated with small amounts of snow snow in variability of degree high the given rism (Laternser andSchneebeli,2003). rism (Laternser is already having a major impact on winter tou- years 20 past the over a.s.l. m 1300 below tions rease in snow days observed at virtually all sta- figure for tourism – from 58 to only 33. The dec- tal number of winter snow days – an important to- decreasethe sharp in a with associated also single day. This decline over the past 20 years is a on recorded not was more or cm 30 of depth snow a example, for 1989/90, of winter the In began. measurements since observed viously pre- never – present the to 1980slate the from – days snow of number the in decrease a lights typical of snow cover. The 20-year average high- green curve shows the large natural fluctuations The elevations. valley at cover snow of decline clear the illustrates time over development The ed since the 1930 at stations in a number of number a in stations at 1930the since ed chen). swiss towns on the Central Plateau. However, t otal snow depth has also been record- t rübsee, säntis (1890), t other stations, other at andermatt, Ulri- engelberg 12.3.2008 16:01:39 Uhr

51 terrestrial observations New snow Long time series and their importance Altogether 15 stations have new snow re- ables of climatological importance, making it cords dating back to the 19th century. Either possible to analyse the influence of warmer MeteoSwiss or the SLF is responsible for these winter temperatures (i.e. more rain than snow) measurements. At 7 stations, new snow has and the predicted increase in winter precipita- been recorded since around 1880 – Sils Maria tion (i.e. more snow in summit regions). New (1864), Guttannen (1877), Elm (1878), Lucerne snow depth is also important for avalanche (1883), Airolo (1885), Chur (1888) and Arosa warning operations, winter tourism and snow (1890). The amount of new snow per day and clearance services. the number of days with new snow are vari-

New snow in Sils Maria 1864 – 2006 Yearly total in cm

Yearly totals for new snow in Sils Maria, 1864– 1000 trend = -0.22cm/year 2006. The blue line illustrates the linear trend for the entire period. However, the trend of -0.22cm trend 800 total new snow per year is not statistically signi- 750 ficant. Sils Maria has the longest new snow series available in Switzerland, going back as far

600 as 1864. Measurements for 6 individual years are incomplete (1913, 1914, 1942, 1950, 2002 and 500 2003), with no data at all for 1913 and 1914. In the other cases, data for at least one winter month 400 (December, January, February) are missing, so that it is not possible to calculate plausible year- 250 sum of new snow per year [cm] ly totals for new snow. The maximum yearly to- water equivalent of snow cover [mm] tal (930cm) was recorded in 1916, and the mini- 200 mum (152cm) in 1953. 0 1860 1880 2000 1920 1940 1960 1980 2000 1943 1950 1960 1970 1980 1990 2000

Measurements in Switzerland (2) Long-term data on snow water equivalents digitized for the period 1943–1985. Since (SWE) are also of interest from an engineer- 1998, after an interruption of more than 10 ing perspective, as these values are used in con- years, data have again been recorded in digital struction standards (SIA NORM 261) for the form. At present, the water equivalent of the maximum snow load on structural elements. snow depth is determined by observers twice The SWE is recorded by various institutions monthly at half of the roughly 80 VG stations. and measurement networks across Switzer- Measurements are mainly performed between land. Compared with measurements of snow November and April, and the data are digitally depth, SWE is determined at a lower tempo- archived. Additional isolated measurements are ral resolution. carried out by hydropower plants and private The first regular observations of SWE within companies, supported by Cryospheric Commis- a measurement network were carried out in sion (EKK) of the Swiss Academy of Sciences 1943 by the ETH Zurich (Hydrology Division (SCNAT). Thus, as part of the observation pro- of the Laboratory of Hydraulics, Hydrology gramme on the Claridenfirn and the Silvretta, and Glaciology/VAW) in cooperation with the Basodino, Gries and Aletsch glaciers, measure- electricity sector. This network was subsequent- ments of the water equivalent of accumulated ly largely integrated into the SLF network, and firn are carried out in the spring with EKK sup- since then the sites concerned have served as port. As well as ground-based and convention- comparison stations (VG). The SWE data col- al measurements of SWE, additional methods lected at VG stations from 1943 onwards were are used for research purposes: for example, 52

Klima_S50_53_Schneebedeckung.indd 52 5.3.2008 15:57:00 Uhr Klima_S50_53_Schneebedeckung.indd 53 wave systemsandgammarayspectrometers. micro- sensors, cable band flat pillows, snow SWE Alptal). blue: richte, Sihlsee; Ga- Wägital, (red: areas catchment in stations of groups and (green) stations individual 1940: to back go series equivalent water longest The water equivalent of snow cover [mm] Area-averaged Snow waterequivalentintheWägital 1943 –2007 1000 250 500 750 is determined using equipment such as such equipment using determined is 0 1943 SWE 1950 inmmforthewholecatchmentasof1 April 1960 1970 tions in the Wägital valley. They account for the total to regard with importance particular Of (1951). Zuoz and The Long timeseriesandtheirimportance Snow waterequivalent Resources required alpine subcatchments for almost 40 years. Indi- out by the cal and climatological studies have been carried warning services. In the Alptal valley, hydrologi- avalanche foreign with exchanged are border the to close stations from data snow system, warning avalanche European the of part As integration International 11includes series The 1943). (since world’s longest lanche warning service and the current support ment sites have been outsourced from the ava- measure- climatological the since uncertain, ries long-term certain Whether assured. ly Continuation of the longest time series is large- vidual hydrological measurements form part of fluhjoch (1937), Davos (1947), Klosters (1948) ments of ments 28 snow depth sites where measurements are http://www.wsl.ch/forschung/forschungsprojekte/hydrology_subalpine_watershed/ (including Engelberg) will be continued is continued be will Engelberg) (including SLF 1980 operates SWE WSL go back to the Weiss-1940sto – back go on snow courses in various sub- SWE VG series for a catchment area 1990 stations where measure- SWE are the various sta- various the are 2000 trend SWE SLF and se- 1994). SWE is therefore1994). SWE expected to show a less be greateret al., snowpack compaction (Rohrer than snowfall. Among the consequences would rather rainfall of form the take increasingly to futurein likely is elevations medium and lower term average on 1 April. Winter precipitation at area. The red line shows the trend for the long- catchment entire the for shown be thus can SWE in Variation band. elevation of function a as SWE area-averaged an into combined are reserveswater the site, stored snowpack the in each at measurements point of basis the On sources willberequired from 2008. re- financial additional continuation, their Toguarantee term. short the in assured only are catchment Wägital the in measurements the by the than snowdepth. pronounced negative trend with climate change see stationssince 1943. Sihl- and Garichte the at out carried rements measu- the continuing currently is GmbH dat the from support financial with the Hydrology Division of the by operated originally network, This ment. spheric Sciences( behalf of the International Association of Cryo- comparison Project conducted (SnowMIP2) on models in the international Snow Model Inter- numerical of validation the for measurements on a weekly to monthly basis serve as reference SWE Zurich, is now being run by Meteodat GmbH Meteodat by run being now is Zurich, catch- the for determined is snowpack the of performed in the spring and the average NADUF values determined at 14 sites in the Alptal FOEN programme ( and IACS ETH ). is open. The valuable The open. is  3.1 River discharge). VAW SLF at the . Meteo- . SWE ETH

5.3.2008 15:57:03 Uhr

53 TERRESTRIAL OBSERVATIONS Klima_S54_57_Gletscher.indd 54 3.7 § 54 Glaciers extraction/landfill and (e) other unvegetat- other (e) and extraction/landfill (d) debris/sand, firn, (c) / rock,glacier (a) (b) categories: following the into subdivided is layer “Ground6. unvegetated cover: areas” SR 172.217.1). DETEC hazards in mountain regions 12c(Art. of the vant as a basis for the assessment of natural rele- are observations glacier from derived be can that trends addition, In areas. ed ( Surveying Cadastral on Ordinance Technical Sport and tection Pro- Civil Defence, of Department Federal the in only glaciers of measurementregular for provides legislation national present, At monitoring. glacier climate-related term No clearly defined legal basis exists for long- Legal basis indicators demonstratingchangesinclimate. key as taken are length glacier and balance mass in changes Long-term temperature. Earth’ssurface the in increase recent significant a of signals clearest the of one is years 25 past the The predominantly negative mass balance of Alpine glaciers over Under Art. 7b of the of 7b Art. Under Organizational Ordinance/ TVAV TVAV , , the information the , SR 211.432.21). OV-UVEK ,

future strategy with regard to relevant issues relevant to regard with strategy future the toring programme. With regard to programme.With toring geo- into the moni- informatics, numerical models) data, (satellite technologies modern incorporate to and affairs) public (research, ( Glaciers for Network trial Terres-Global the measurementsinto existing ( Sciences ( mission Com- Cryospheric the by reviewed being ly current- are velocities) flow and temperature inventory, glacier firn change, length change, /volume balance (mass studied variables The Measurements inSwitzerland of the accumulation of snow and the loss of loss the and snow of accumulation the of result net the – glacier a of balance mass The in detailbelow. described are variables glacier three These 5. change in 4 Tier and glacier inventories in Tier length 3, Tier in balance mass follows: as ed GTN-G EKK SCNAT tier system, data can be integrat- be can data system, tier o te ws Aaey of Academy Swiss the of ) ). The aims are to integrate to are aims The ). GTN-G ), to define to ), GCOS and

Hydraulics, Hydrology and Glaciology ( Glaciology and Hydrology Hydraulics, of Laboratory the by financed and out carried are measurements balance mass The glaciers. glaciers and volume long-term changes for 25 termine area-averaged mass balances for three cier. The direct method is currently used to de- of spatial changes across the surface of the gla- changes in volume are determined on the basis duction of a in digital which elevation model), (pro- method geodetic-photogrammetric the about of 10intervals by at years calibrated be to need measurements situ in These surface. and a number of stakes drilled into the glacier pits snow using year a once least at formed measurements are per-i.e. ciological method; gla- direct the by determined is balance mass glacier.The entire the across taken urements meas- on based value, area-averaged an is – snow or ice mainly caused by melting (ablation) of the ETH Zurich, with support from the 5.3.2008 16:29:28 Uhr VAW EKK ) ,

cumulative mass balance [m w.e.] −20 -20 0 0 9014 9018 2000 1980 1960 1940 1920 1920 1940 Silvretta Gries Basòdino Silvretta Gries Basòdino 1960 1980 2000 Klima_S54_57_Gletscher.indd 55

and privatebodies. companies generation power offices, federal glaciers). measurements (22 change volume with glaciers additional blue: glaciers); (3 measurements balance mass with Swiss Glacier Monitoring Network. Red: glaciers cumulative mass balance [m w.e.] Cumulative massbalanceinmwaterequivalent Mass balanceseriesforthree Swissglaciers −20 -20 0 0 9014 9018 2000 1980 1960 1940 1920 1920 (Continued onpage56) (Continued 1940 and Plattalva glaciers; however, measurements Limmern glacier,to Silvretta1947the and for ments of mass balance go back to 1914 thefor the in glacier period –1910.1884 Rhône Long-term in situ measure- the on out carried first were balance mass of Measurements Long timeseriesandtheirimportance Mass balance glaciers the on out carried being still rently cur- are measurements Thus, 1985.in tinued discon- were glaciers last-named two the on Silvretta Gries Basòdino Silvretta Gries Basòdino http://glaciology.ethz.ch/swiss-glaciers 1960 1980 2000

should be continued primarily on the three the on primarily continued be should volume long-term allowing available are data glaciers, 25 about For resolution. annual at Corbassière,(Giétro, Allalin and Schwarzberg) glaciers other four for and resolution, sonal 1914) and Grosser Aletsch (since 1918) at sea- (since Claridenfirn the for available are stakes individual from Measurements 1991). (since past andassessfuture developments. the reconstruct to data climate with polated tion, long-term series of this kind can be extra- addi- In measurements. isolated of polation remote sensing data for and spatio-temporal extra- models balance mass of combination the in lies approach promising One records. these of utilization enhance to methods ther fur- developing to given be should priority series, time long other the For glaciers. 3 Tier a From years. at intervalsof–30 10 changes to be calculated for the past 100 years er network), Gries (since 1961) and (since Gries network), er dens- a 1914; 1959since with (since Silvretta ape vr h ps 1010 years 100–150 past the over sample larger a for series time balance mass homogenized preparing for – changes volume determined additionally with conjunction in – basis essential the providepresented series balance mass threeThe method. glaciological the by Gries and Basòdino glaciers, determined Silvretta, glaciers the for equivalent) water m (in balance mass Cumulative (Huss etal.,2008). (Huss GTN-G esetv, measurements perspective, basòdino 5.3.2008 16:29:32 Uhr

55 TERRESTRIAL ObSERVATIONS Length change Long time series and their importance The first regular glacier observations in the ciers currently surveyed (including 73 assigned Swiss Alps began in 1880 with annual meas- priority 1). However, as a result of the increas- urements of changes in length. Since 1893, ing disintegration of many glacier tongues in these data have been systematically collected recent years, unequivocal determination of in an internationally coordinated manner. length change is sometimes problematic, and Thanks to the continuous efforts of numerous the continuation of individual series should be observers, Switzerland has one of the world’s critically reviewed in each case. To address the most extensive monitoring networks. Accord- methodological challenges now arising, the ing to the glacier evaluation report, monitoring use of new technologies should increasingly is to be continued for at least 97 of the 120 gla- be considered.

Changes in length of three Swiss glaciers 1880 – 2006 Cumulative annual measurements in m

Cumulative annual measurements of length change (in m) for three glaciers 0 0 of different sizes (length in km) show- ing different responses and adapta- bility to changes in climate. The figure −500-500 illustrates how the size of a glacier influences the extent and duration −1000-1000 of fluctuations. Thus, Switzerland’s larger glaciers (Grosser Aletsch) have retreated continuously since obser- −1500-1500 vations began. In contrast, steeper mountain glaciers (Trient) show decadal variations, while small glaciers

cumulative length change [m] −2000-2000 (Pizol) show low-amplitude yearly PizolPizol (0.5km) (0.5 km) variations (Glaciological Reports, −2500-2500 TrientTrient (4.3km) (4.3 km) 1881–2006). GrosserGrosser Aletsch Aletsch (22.9km) (22.9 km)

19001900 19501950 20002000

Measurements in Switzerland (2) The monitoring network established in Swit- or more complex theodolite or GPS surveys. In zerland over the years includes length change addition, remote sensing systems (aerial pho- measurements for glaciers of all sizes and tography and satellite imagery) are increasing- types, ranging from the small glacier patch ly being used. To date, the aerial photographs through cirque and mountain glaciers to large produced by swisstopo at regular intervals for valley glaciers. While glaciers of the last two several decades have not been available for use types are well represented, small glaciers are in systematic analysis. In the future, field meas- substantially underrepresented given their urements will still be required for calibration of actual numbers (according to the glacier in- remote sensing data. ventory, 80% of the glaciers are smaller than 1km2). The length change measurements Glacier inventories represent Tier 5 obser- are carried out by the VAW in cooperation vations in the GTN-G system, recording the with the cantonal forest agencies, federal characteristics of each glacier according to a offices, hydropower companies and private standardized scheme. In addition to the name, bodies, with financial support from the EKK. coordinates and hydrological catchment, these Changes in length continue to be determined include details of the area, length, lowest and mainly by field measurements, carried out by highest point, aspect and survey time, as well local residents. Among the approaches used as a morphological classification. Inventories are simple methods involving measuring tapes allow individual measurements (e.g. of mass and portable distance meters (e.g. binoculars) balance) to be extrapolated to an entire sam- 56

http://glaciology.ethz.ch/swiss-glaciers

Klima_S54_57_Gletscher.indd 56 5.3.2008 16:29:34 Uhr Klima_S54_57_Gletscher.indd 57 1340km was area glaciated total the data, inventory tionwide (e.g. loss of ice volume). According to ple and thus enable changes to be assessed na- veyed. sur- glaciers 120 the of rest the blue: glaciers; 1 priority 73 Red: Network. Monitoring Glacier Swiss the within measurements change Length Glacier boundariesaccording toSwissglacierinventoriesof1850and1973 Retreat ofglaciersintheAletschregion 2 in1973 andonly1050km 2 in2000. an inventory from around from inventory an ed from contemporary sheets, plane-table sur- of autumn the in taken photographs aerial from guarantees. Additional financial resources areresources financial Additional guarantees. ducted on a voluntary basis without long-term the long term. At present, they are largely con- in assured not is measurements glacier of ing fund- the basis, legal a of lack the to Owing veys and analysis of aerial photographs. For the Long timeseriesandtheirimportance Inventories Resources required This project, which aims to complete the global the in e.g. worldwide, applied now are – systems information geographical subsequent derivation of inventory data using cation based on multispectral satellite data and inventory glacier Swiss the for developed methods The integration International individual in changes determine Toarea. ed remainingglaciat- the of 85% about covering was compiled from multispectral satellite data, 1998/99 be officially responsible for Tier 5 of the glacier inventory using satellite data, is soon to A Swiss glacier inventory ( inventory glacier Swiss A http://www.glims.org 1973 . Supplementing this publication was publication this Supplementing . period, a new inventory ( inventory new a period, SGI 2000 – automatic glacier classifi- SGI 1850 ) was compiled was ) GLIMS , reconstruct- , SGI 2000 SGI project. GTN-G to take account of currently glaciated areas. Digital terrain tant contribution, e.g. by allowing hydrological modelling impor- an make inventories the hazards, natural of area the In 2004). al., et (Paul decades several of intervals at geomorphological investigations and should be repeated and climatological hydrological, glaciological, numerous at a given point in time. They provide an essential basis for record basic data for the largest possible sample of glaciers cier inventories for the Aletsch region. Glacier inventories gla- Swiss 1973(blue) and 1850(red) the of Comparison model: swisstopo; satellite data: NPOC/Eurimage. satellitedata: swisstopo; model: ) . glacier outlines from is required in each case. In various projects, the (outline) preciseboundary the glacier of edge glaciers resulting from climate change, knowl- GCOS fore be assured in the long term through Swiss aerial images. Glacier monitoring should there- also required for the acquisition of satellite and ( lished by the World Glacier Monitoring Service glaciers, which are collated, archived and pub- zerland’s contribution to global observations of ciers) and length (120 representglaciers), Swit- database, are freely available. ( Space from Measurements Ice Land Global the into integrated outlines, glacier the Digital Atlas of Switzerland. The SGI 2000 in published been now have these and tized (Silvretta, Gries, (Silvretta, glaciers 3 threemeasurementsthe Tier The at measurements of changes in volume (25 gla- (25 volume in changes of measurements  4.3 funding. WGMS ). asòdino), together with the with together basòdino), 1850 and 1973 were digi- GLIMS ) 5.3.2008 16:29:37 Uhr

57 TERRESTRIAL ObSERVATIONS 3.8 Permafrost Permafrost reacts sensitively to changes in climate such as the rising air temperatures currently observed. Thawing leads to increased ground instability at high altitudes, which may have adverse impacts, e.g. on cableways, hiking paths, pass roads and mountain villages.

0.00.0

Schafberg (9.2m) -0.5-0.5 Schilthorn (10.0m) Muragl (9.6m) Gentianes (9.6m) --1.0 1.0 M. Barba Peider (10.0m) Murtèl (11.5m) --1.5 1.5

temperature [°C] -2.0-2.0

-2.5-2.5

-3.0-3.0 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Measurements in Switzerland “Permafrost” is the term used to describe a tutions. PERMOS, currently still under develop- § Legal basis subsurface layer where the temperature does ment, comprises stations on alpine scree slopes Permafrost monitoring is only provided for not exceed 0 °C throughout one year. In the and at rock sites of varying slope and aspect. indirectly in national legislation, in connec- Alps, permanently frozen soil and rocks of this Measurements are performed in various ways: tion with the natural hazards arising from kind mainly occur above the treeline. (i) at 16 sites, temperature depth profiles are changes in permafrost. Under Article 12c of Permafrost lies below the active layer, which is determined using boreholes, allowing measure- the DETEC Organizational Ordinance (OV- up to several metres thick and has positive or ments at depths of up to 100m (these indicate UVEK, SR 172.217.1), the federal authorities negative temperatures depending on the sea- the thickness of the active layer and changes are required to ensure protection against son. It exists unseen in rock faces and across in the temperature of permafrost); (ii) in 5 are- natural hazards. The Federal Office for the summit areas or scree slopes. In polar regions, as, ground surface temperatures are measured, Environment (FOEN) is responsible for this permafrost can be more than a kilometre thick, permitting conclusions as to temperatures un- task. Under Article 3d of the ETH Board Or- while its thickness in our latitudes ranges from derground and thus the occurrence of perma- dinance on Research Institutes of the ETH decametres to several hundred metres. It is es- frost; and (iii) in 8 areas, aerial photographs are Domain (SR 414.161), the Swiss Federal timated that permafrost underpins about 5% regularly taken and analysed. Institute for Forest, Snow and Landscape of the area of Switzerland, i.e. about twice the The measurement sites are divided into three Research (WSL) is also active in the area of area covered by glaciers. categories: A sites have been included in the permafrost. Observations of permafrost are coordinated by PERMOS programme and operations will con- PERMOS (Permafrost Monitoring Switzerland), tinue; B sites will initially continue to be oper- based at the University of Zurich. Measure- ated and will be re-evaluated in 2009; C sites ments are carried out by various partner insti- are no longer included in PERMOS. 58

Klima_S58_59_Permafrost.indd 58 5.3.2008 16:45:46 Uhr Klima_S58_59_Permafrost.indd 59 is geographicallyheterogeneous. a product of research projects, their distribution B As A sites the sites (blue). stations (red); were PERMOS. network monitoring permafrost The Monthly averagein˚Catadepthofaround 10m Permafrost temperatures from sixboreholes 1987 −2006 temperature [°C] -3.0 -2.5 -2.0 1.5 - 1.0 - -0.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.0

19871987 Murtèl (11.5m) M. Barba Peider(10.0m) Gentianes (9.6m) Muragl (9.6m) Schilthorn (10.0m) Schafberg (9.2m) 19881988 19891989 19901990 19911991 19921992 19931993 19941994 19951995 h qaiy n ln-em otnain of continuation long-term and quality the motne o te Swiss the for importance the within ed operat- stations The internationally. pared com- even long, are series time longest The 1990s.the in institutes partner versity-based PERMOS Long timeseriesandtheirimportance frost ( frost Perma- for TerrestrialNetwork Global the of monitoring activities, and research international of context the In integration International course of research the projects addressing in process- up set mainly were stations existing The sites. these at assured is measurements FOEN between agreement an under 2010 of end the until assured is office coordination the of of funding The Resources required

be to is use increasing measurements, situ in lished within 19961996 http://www.permos.ch 19971997 , GTN-P SCNAT

19981998 uni- of number a by established was ), which is currently being estab- being currently is which ), GCOS/GTOS

and MeteoSwiss. Subsequently,MeteoSwiss. and 19991999 PERMOS

PERMOS 20002000

PERMOS 20012001 network are of major of are network measurements and measurements . Here, in addition to 20022002 GCOS is a component 20032003

20042004 as Office, 20052005 20062006 Ideally, there should be at least two least at be should Ideally,there dium term in connection with various activities. pansion of the network is planned for the me- operated until 2009 and then re-reviewed. Ex- technically standardized, while B sites are to be and methodologically and priority a as tained division into categories: A sites are being main- funded bytheSwiss be to is monitoring climate for required sites measurement permafrost of proportion the including three Swisssites. boreholes, nine at studies involved project ( The modelling inspaceandtime. numerical and data sensing remote of made al., 2007). et Mühll temperatures (Vonder air summer and conditions snow winter on particular in pend is clearly apparent. Permafrost temperatures de- variation seasonal depth, this at noticeable not are fluctuations daily short-term As depth. this to penetrate to signal the for year a half about takes It 2002. and 1995/1996 in interruptions boreholes reveal three periods of warming, with selected six in 10m around of depth a at ured meas- temperatures permafrost of series These for monitoring purposes. This also explains the available also are they but questions, related stations ineachalpineclimateregion. PACE EU ) project also contributed to emfot n Ciae n Europe in Climate and Permafrost GCOS Office. GTN-P PERMOS . This

5.3.2008 16:45:50 Uhr

59 TERRESTRIAL OBSERVATIONS Klima_S60_61_Landnutzung.indd 60 3.9 § 60 Federal Statistical Surveys (SR 431.012.1).Federal StatisticalSurveys(SR specified in the Ordinance on the Conduct of are data statistical of collection the erning tional responsible agency. The principles gov- The Federal Statistical Office ( society, land and environment in Switzerland. economy, population, the of development manner,independent cally and state the on scientifi- a in data, representative obtain to 431.01),arerequiredauthorities federal the SR (BStatG; Act Statistics Federal the Under Legal basis mine theeffects oflandusechangeontheclimate. deter- to needed is conditions current and historical on mation Infor-use. land in changes with greenhouseassociated of gases uptake or release the by affected is system climate The climate. regional the influences transformation This use. of change a undergoes Switzerland in land of ha 4000 about year, Each Land use FSO ) is the na- Land Cover Land 1990differdatasets The statistics. (Coordinated Information on the Environment) tics were integrated into the European Statis- Use Land Swiss 1979/85 the base, tion informa- comparable and objective reliable, a As transboundary environmental policy calls for od andadaptedtothenewnomenclature. being reviewed according to the current meth- in conducted 1979–1985and 1992–1997,are surveys, two first The categories. basic 72 of ty with earlier data is assured by the definition of land use and 27 of land cover. Comparabili- categories different 46 employs survey latest The Switzerland. of area total the of for 16% are available –2009) third survey period (2004 the of results 2007, spring of As analysed. are Topography(swisstopo) of Office Federal the by produced photographs aerial purpose, this For average. on years 12every use land Measurements inSwitzerland The FSO Land Use Statistics recordin Statistics changes Use Land CORINE

half ofthe Assessment Unit compares Unit Assessment Landscape Research ( and Snow Forest, for Institute Federal Swiss the into integrated be to are is now available. The Swiss Land Use Statistics on land use and land use changes across Europe vironment Agency ( the With resolution. spatial and ture nomencla- types, use land of definition the in Agency ( Space European the from support With base. by the European Union and the EuropeanEn- the and EuropeanUnion the by by various project partners (e.g. (e.g. partners project various by conducted are surveys landscape ecosystems, protected nationally preserve to order In ucts. forest inventory data and global satellite prod- Land Cover of the Data User Element programme. At the At programme. Element User Data the of satellite data from the GlobCover project, part ESA FOEN 2000 ), CLC2000 . project EEA WSL ), an updated database is being updated with CLC2000 ), the Land Resource CORINE CLC2000 WSL Zunahme derlebendigenBiomasseimWald 6.3.2008 10:12:59 Uhr , supported data with data ) on be- on ) CORINE data-

-16 000 -12 000 CO2 [Gg] 12 000 1 -8 000 -4 000 4 000 8 000 6 000 -16'000 -14'000 -12'000 -10'000 10'000 12'000 14'000 16'000 -8'000 -6'000 -4'000 -2'000 2'000 4'000 6'000 8'000 0 0 9019 9219 9419 9619 9819 0020 0220 042005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 Decrease oflivingbiomassinforest Land usechangeandsoil Increase oflivingbiomassinforest Zunahme derlebendigenBiomasseimWald Klima_S60_61_Landnutzung.indd 61 CO (19%); darkgreen: geographicaldata(21%). (19%); cantonal data light (15%); green: communal data Status of the 3 Sources andsinksingigagrams Swiss Land Use Statistics (2004–2009). Orange: Orange: (2004–2009). Statistics Use Land Swiss

-16 000 -12 000 CO2 [Gg] 12 000 1 -8 000 -4 000 4 000 8 000 2 6 000 -16'000 -14'000 -12'000 -10'000 10'000 12'000 14'000 16'000 balance for land use changes in Switzerland 1990 −2005 -8'000 -6'000 -4'000 -2'000 2'000 4'000 6'000 8'000 0 0 9019 9219 9419 9619 9819 0020 0220 042005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 rd Decrease oflivingbiomassinforest Land usechangeandsoil Increase oflivingbiomassinforest

survey period 2007) of (July the As a signatory to the to signatory a As Statistics according to the methodology used methodology the to according Statistics analysis of the and 1979/85 Land 1992/97 Use re- The periods. these over determined ably reli- be cannot use land in changes surveys, these in inconsistencies to owing However, 1972.and 19521912, in 1923/24, out ried car- previously were surveys use land Swiss Long timeseriesandtheirimportance Resources required Use Land Use, “Land for balance gas house The year,each gases taking 1990year.base the as greenhouse of sinks and sources of inventory national a compile to commitment a has land ( Change Climate on tion integration International ious users as geographical basic data. These data. basic geographical as users ious var-to available made and Statistics Use Land the in published are data available latest The http://www.statistics.admin.ch FOEN is responsible for this task. A green- UN Framework Conven- Framework UNFCCC ), Switzer- ), to guidelines issued by the pared in the greatest possible detail according Gas Inventory. Greenhouse the for balances carbon mining deter-for basis excellent providesan also This (1979–2009). period lengthy a over changes ting statistically based conclusions on land use permit- other, each with comparable directly ble for ble indispensa- areregion, by down broken data, Statistics andtheNationalForest Inventory. sector. This is based on data from the Land Use precise carbon balance is required for the forest Change and Forestry” ( for the current survey makes all three datasets by theStatisticsAct. LULUCF storms (windthrow) and (b) the and oc- (b) storms (windthrow) the occurrence of severe(a) ticular: par- in factors two by determined year, to year from variations large land since 1990. However, there are Switzer- in sink a as acted has use land average, on that, show lated CO sive factor. deci- a be will production power and heat for wood energy of use the future, In growth). new (little summers dry and hot of currence The greenhouse gas balances calcu- 2007). (FOEN, forestry and change use land use, land with associated 2 . These activities are governed governed are activities These . emissions (+) and removals (-) (-) removals and (+) emissions LULUCF IPCC ) has to be pre- . A particularly 6.3.2008 10:13:01 Uhr

61 TERRESTRIAL OBSERvATIONS 3.10 Forest ecosystem Forests are not only a natural resource – they also fulfil protective and recreational functions. A changing climate affects forests by altering the length of the vegetation period – affecting the future distribution limits of individual tree species. With long-term observations, impacts on the forest ecosystem can be assessed.

200200

-200-200

-400-400 matric potential [hPa]

-600-600

-800-800 Jan97 Jan98 Jan99 Jan00 Jan01 Jan02 Jan03 Jan04 Jan05 Jan06 Jan07 depth 30cm depth 100cm

Measurements in Switzerland Since 1985, the state of Switzerland’s forests are conducted under various stress scenarios. § Legal basis has been documented by the Sanasilva Inven- To this end, numerous site-specific variables are With the partial revision of the Federal For- tory, which focuses on tree health. These sur- permanently monitored. On the LWF plots, me- est Act (WaG, SR 921.0), the Federal Coun- veys are carried out in July and August, using teorological measurements are carried out au- cil intends to safeguard the forest’s protective a 16 x16km sampling grid (approx. 50 study tomatically according to international stand- function and natural diversity over the long sites). The main characteristics assessed are (a) ards, with one station located in the stand and term. Federal forest policy is based on the crown transparency, (b) crown discoloration a second in a nearby unstocked area. In addi- Swiss National Forest Programme (WEP-CH) and (c) mortality; growth rates are studied by tion, stand, vegetation, soil and nutrient data from 2002/03. The Forest Act and Ordinance the National Forest Inventory (LFI). are collected at varying temporal resolution are further elaborated in circulars addressed Under the federal Long-term Forest Ecosys- (hourly to yearly). At the Seehornwald research to the cantonal enforcement authorities. The tem Research (LWF) project, more intensive station (Davos), microclimate and tree physio- Federal Office for the Environment (FOEN) and wide-ranging studies have been pursued logical data have been recorded for two de- supports forest monitoring projects devel- since 1994 as part of an integrated approach cades. Covering a period of about 10 years, al- oped by the Swiss Federal Institute for For- to forest monitoring. At 18 monitoring sites most continuous records of gas exchange rates est, Snow and Landscape Research (WSL). (LWF plots) in Switzerland, (a) external anthro- are available for a forest patch and for individ- Under the ETH Board Ordinance on Research pogenic and natural influences (air pollution, ual trees and branches. Over the same period, Institutes of the ETH Domain (SR 414.161), climate) are evaluated, (b) changes in impor- stem radius changes and sap flow rates have the WSL is responsible for forest ecology ac- tant components of the forest ecosystem are also been continuously measured. tivities. assessed, (c) forest health indicators are devel- Other specific areas are being studied as part of oped, and (d) comprehensive risk assessments forest fire ecology projects ( 3.11 Forest fires). 62

Klima_S62_63_Waldoekosystem.indd 62 6.3.2008 10:24:48 Uhr Long time series and their importance The LWF project, involving permanent mon- the measurements at these sites and the LWF itoring and experimental sites, improves our plots, bioclimatological studies are carried out understanding of the impacts of air pollution at the subalpine experimental afforestation site and climate change. The systematic sampling on the Stillberg mountain near Davos. Here, grid of the Sanasilva Inventory has become less microclimatological variables have been stud- dense over the years. Around 8000 trees were ied at four plots since 1975. In larch stands in surveyed at 700 points in a 4 x 4 km grid in the the Engadine and near Davos, measurements period from 1985 to 1992; around 4000 trees of needle growth have been performed since in an 8x 8 km grid in 1993, 1994 and 1997; and the 1960s to determine how the development around 1100 trees in a 16 x16km grid in 1995, of this tree species is affected by the larch bud 1996 and from 1998 onwards. In addition to moth and by climate change.

Water availability for vegetation 1997 − 2006 Soil matrix potential in hPa at the LWF vordemwald site (Central Plateau, 480 m a.s.l.)

200200 Water availability for vegetation at the LWF Vordemwald site, 1997–

2006. The lower the values, the ATIONS v 00 more difficult it is for trees to ex- tract water from the soil. On the OBSER LWF plots, the matrix potential is -200-200 measured to study the effects of drought on trees. The drier it be- came in 2003 (an exceptionally hot -400-400 year), the greater the decrease in TERRESTRIAL

matric potential [hPa] tree growth compared with the wet 2002 (Graf Pannatier et al., 2007). -600-600 With long-term monitoring of the matrix potential, it is possible to -800-800 demonstrate the effects of climate Jan97 Jan98 Jan99 Jan00 Jan01 Jan02 Jan03 Jan04 Jan05 Jan06 Jan07 change on soil water availability for depth 30cm vegetation. depth 100cm

International integration The aims of the LWF project are in agreement submitted yearly to the Joint Research Cen- with those of the International Co-operative tre (JRC) at Ispra (Italy) and to the ICP Forests Programme on Assessment and Monitoring Programme Co-ordinating Centre in Hamburg. of Air Pollution Effects on Forests (ICP For- Other data are used for reporting to the Minis- ests). This programme was launched in 1985 terial Conference on the Protection of Forests under the Convention on Long-range Trans- in Europe (MCPFE) Criteria and Indicators. The boundary Air Pollution (CLRTAP) of the United LWF is part of the International Long-Term Eco- The 18 LWF research plots (red), the Stillberg Nations Economic Commission for Europe logical Research Network (ILTER). experimental afforestation site (green) and the (UNECE). The various measurements are larch sites in the Engadine (blue).

Resources required Continuation of the LWF and Sanasilva surveys studied more or less intensively. The larch stud- is assured in the medium term. Depending on ies are guaranteed over the long term. the resources available, the Stillberg site can be

http://www.wsl.ch/forschung/forschungsprogramme/target/oekologie/index_EN

Klima_S62_63_Waldoekosystem.indd 63 6.3.2008 10:24:52 Uhr 3.11 Forest fires Forest fires may be caused either by human activities or by natural factors. The effects of a lack of precipitation and insufficient moisture can persist over several years. Fires impair the protective function of forests. The regional forest fire risk may be affected by changes in climate.

200 summer 180 Sommerbrände Winterbrändewinter 160 Laufmittel9-year running auf mean 9 Jahren 140 120 100

number of ﬁres 80 6060 4040 2020 00 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Measurements in Switzerland Forest fire statistics are an indispensable in- mation on more than 6600 forest fire events Legal basis strument for forest and fire services planning had been stored in this database, in some cases § th Under Article 77 of the Federal Constitution fire-fighting facilities and prevention measures. dating back to the 19 century. From 1980, (SR 101), the federal authorities are required With forest fire data going back years or even forest fires were also systematically recorded by to ensure that forests can fulfil their produc- decades, analyses of various kinds can be car- canton Graubünden (approx. 350 records by tive, protective and welfare functions. Ac- ried out: (a) to identify areas or forest types 2004). In the cantons of Valais and Uri, data cording to the Forest Act (WaG, SR 921.0), particularly susceptible to forest fires, (b) to as- on the most relevant forest fires since the be- forests must contribute to the protection of sess the forest fire risk on the basis of mete- ginning of the 20th century were compiled human life and assets. Under the Forest Or- orological conditions (risk index) as an aid to through archive research carried out by the for- dinance (WaV, SR 921.01), the cantons are decision-making concerning fire bans, (c) to est and fire services. The database is centrally required to take measures against causes optimize prevention measures, and (d) to as- managed by the WSL, so that data can be used of damage that may endanger forests, in- sess the historical effectiveness of changes in in particular for research purposes. cluding the establishment of permanent fire forest fire control. In general, forest fire be- Global forest fire maps are produced using sat- prevention facilities. Cantonal forest services haviour can be classified into four types: sur- ellite data and integrated into the World Fire monitor forest fire risk levels and prohibit fire face fire, crown fire, spot fire and ground/root Atlas. It is based on data from the radiome- lighting in or near forests. Under the Federal fire. In 1993, as part of the National Research ters ATSR and AATSR onboard the ESA satel- Act on Meteorology and Climatology (MetG, Programme NRP 31, the WSL established a lites ERS-2 and Envisat. The Standard Forest Fire SR 429.1), the Federal Office of Meteorology forest fire database for southern Switzerland Product based on MODIS data is a contribution and Climatology (MeteoSwiss) is responsible (canton Ticino, southern Simplon region and to the GTOS programme Global Observation of for issuing forest fire risk warnings. Graubünden southern valleys). By 2006, infor- Forest and Land Cover Dynamics (GOFC-GOLD). 64

Klima_S64_65_Waldbraende.indd 64 6.3.2008 10:34:46 Uhr Long time series and their importance The long-term forest fire statistics held in the be analysed, e.g. the points of origin of light- central WSL database are valuable for ana- ning fires in the hot summer of 2003. In a WSL lysing forest fire trends for specific regions project designed to study ecological resilience over lengthy periods. Ultimately, data is to be after fire in Central Alpine valleys, the forest recorded nationwide. One such analysis, al- fire patch of Leuk is the subject of a long-term beit restricted to 20 years, concerns the dis- monitoring study. Here, local weather condi- tribution of lighting-induced fires in the Alps. tions have been recorded since 2004, as in LWF A spatial distribution pattern also provides infor- monitoring ( 3.10 Forest ecosystem), and mation on fire perimeters and the fire regimes vegetation and biodiversity have also been in the region concerned. At the same time, the studied. distribution of a specific type of forest fire can

Forest fires in southern Switzerland 1900 − 2003 Number of fires, by season

200 The yearly statistics for the period summer 1900–2003 come from the database 180 Sommerbrände 180 on forest fires south of the Alps. winter Winterbrände th 160 In the 20 century, the average 9-year running mean number of fires per year occurring Laufmittel auf 9 Jahren OBSERVATIONS 140 south of the Alps increased from 30 to 80 from the 1960s onwards. Since 120 the 1990s, the number of forest 100 fires has declined again. The excep-

tional events of 1973 led to a reor- TERRESTRIAL 80 number of ﬁres 80 ganization of the Ticino fire serv- 6060 ice. Thanks to this reorganization, the yearly burned area decreased 4040 markedly from 1980 (Conedera et al., 1996). 2020 00 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

International integration The Global Fire Monitoring Center (GFMC) Reduction (ISDR). The GFMC publication Inter- provides early warnings and monitoring of fire national Forest Fire News regularly includes re- events and archives global fire information. ports from the WSL. In addition, the WSL is a The GFMC is based at the Max Planck Insti- new member of the European Commission’s tute for Chemistry at Freiburg and is support- Forest Fire Expert Group. ed by the German Federal Foreign Office, the Data from the European Forest Fire Informa- Federal Ministry for Education and Research, tion System (EFFIS) are published by the Euro- Starting points of forest fires caused by light- and the UN International Strategy for Disaster pean Commission. ning in the summer of 2003: high (red) and low (blue) degrees of certainty as to the time of in- ception.

Resources required Routine maintenance of forest fire statistics is of the database is carried out in projects requir- assured by the WSL. Upgrading or expansion ing separate funding.

http://www.wsl.ch/waldbrand

Klima_S64_65_Waldbraende.indd 65 6.3.2008 10:34:49 Uhr 3.12 Phenology Plant growth and development are strongly influenced by climatic conditions. Accordingly, the trends observed in phenological time series are largely attributable to climate warming in recent decades. The results of phenological observations are in particular applicable in healthcare (pollen forecasts) and in agriculture.

30.4.30.4.

16.4.16.4.

2.4.2.4.

19.3.19.3.

5.3.5.3.

date 19.2.19.2.

5.2.5.2.

22.1.22.1.

8.1.8.1.

25.12. 18001800 1820 1820 1840 1840 1860 1860 1880 1880 1900 1900 1920 1940 1960 1980 2000

Measurements in Switzerland The first phenological observation network in the forest phenology programme initiated by § Legal basis Switzerland was created in 1760 by the Eco- the FOEN. Under the Federal Act on Meteorology and nomic Society of Bern. About 100 years later, Trees, shrubs and herbs are taken as the most Climatology (MetG, SR 429.1), the federal from 1869 to 1882, the Forest Agency of can- significant indicators of climatic changes: authorities are required to record meteoro- ton Bern carried out a phenological observa- beech, hazel, larch, spruce, lime, wood ane- logical and climatological data continuously tion programme in forests. mone, dandelion and daisy. Observations are throughout Switzerland. In addition, they are A national phenological monitoring network passed on to MeteoSwiss at the end of the responsible for the implementation of meas- was established by MeteoSwiss in 1951. This year for use in studies on the long-term effects ures contributing to the long-term preser- now comprises some 160 stations, distribut- of the climate on plant development. To per- vation of an intact environment. The Fed- ed across various regions and elevations of mit conclusions on the current state of vege- eral Office of Meteorology and Climatology Switzerland. The lowest-lying station is lo- tation, data are submitted immediately for cer- (MeteoSwiss), which is responsible for these cated in Ticino (Vira) at 210m a.s.l., and the tain phenophases. These provide a basis for tasks under the Federal Ordinance on Mete- highest-altitude station is in the Engadine reports on vegetation status. orology and Climatology (MetV, SR 429.11), (St.Moritz) at 1800m a.s.l. Observations of pollen distribution – anoth- conducts detailed phenological observations. Each year, observers record the dates of leaf er phenophase – are of major public health Also involved in phenological aspects of bio- unfolding (needle appearance), flowering, relevance. They are carried out by the Na- diversity, agriculture and healthcare are the fruit ripening, leaf colouring and leaf fall for tional Pollen Monitoring Network NAPOL Federal Office for the Environment (FOEN), selected wild plants and crops. These obser- ( 2.13 Pollen). the Federal Office for Agriculture (FOAG) and vations cover 26 plant species and 69 pheno- the Federal Office of Public Health (FOPH). phases. In 2001, MeteoSwiss also took over 66

Klima_S66_67_Phaenologie.indd 66 6.3.2008 10:42:10 Uhr Long time series and their importance Since 1808, the bud burst date for horse ning of the 1950s. The selection of the coun- chestnut has been recorded in Geneva. This try’s most important observation sites includes is Switzerland’s longest phenological time a wide variety of regions and elevations, tak- series. Of equal importance is a second his- ing into account the quality of observations of torical series – cherry tree flowering dates at tree, shrub and herb phenophases, preferably the rural Liestal station – which goes back to of long duration. Twelve of the most important 1894. Observations from the stations of the sites are Liestal, Davos, Enges, Murg, Prato- national phenological monitoring network Sornico, Rafz, Sarnen, St.Moritz, Trient, Val- are more recent, going back to the begin- sainte, Versoix and Wildhaus.

Horse chestnut bud burst Geneva 1808 − 2007 Dates of onset and running average

30.4.30.4. The onset of horse chestnut bud burst in Geneva varies widely. In 16.4.16.4. 1816, for example, it was observed 2.4.2.4. on 23 April, while for 2003 it was already recorded on 29 December

19.3.19.3. OBSERVATIONS 2002. From around 1900, a clear 5.3.5.3. trend towards earlier onset is ob-

date vious. This is attributable not only 19.2.19.2. to global climate change, but also

5.2.5.2. to changes in the local city climate TERRESTRIAL (Defila and Clot, 2001). Given the 22.1.22.1. strong temperature dependence of 8.1.8.1. plant development, phenological time series are good indicators of 25.12. 18001800 1820 1820 1840 1840 1860 1860 1880 1880 1900 1900 1920 1940 1960 1980 2000 the impacts of climate change.

International integration Switzerland is part of the European Phenolo- tion Research Initiative in Alpine Environments gy Network (EPN), and the Birmensdorf WSL (GLORIA) aims to establish a worldwide long- site participates in the European International term observation network of sites collecting Phenological Gardens (IPG) observation pro- data on vegetation in Alpine environments. gramme. In addition, under COST-725, joint Switzerland is contributing to this initiative efforts are being undertaken to harmonize with two sites – one in the National Park and observation guidelines and to build a Euro- one in Valais. The main sites for phenological observations in pean reference data set. The Global Observa- Switzerland, covering a variety of regions and elevations, where long observation series of tree and shrub phenophases are available.

Resources required The Geneva and Liestal sites are not part of the trast, the continued operation of the twelve phenological monitoring network; as they are main phenological stations is assured under the operated on a voluntary basis, the observations legal mandate of MeteoSwiss. are not considered to be guaranteed. In con-

http://www.meteoswiss.ch/web/en/climate/climate_since_1864/phaenologie.html

Klima_S66_67_Phaenologie.indd 67 6.3.2008 10:42:14 Uhr 4.1 GEBA The Global Energy Balance Archive (GEBA) systematically stores data on energy fluxes from around 1600 stations worldwide. Energy fluxes at the earth’s surface largely determine global heat transport and atmospheric circulation. To understand the climate and climatic changes, therefore, a detailed knowledge of the variations in the energy balance is essential.

180180 170170 160160 ]

2 150150 140140 130130 120120 110110 100100 global radiation [ W/m 9090 8080 7070 1920 19201930 19301940 19401950 19501960 19601970 19701980 19801990 19902000 20002010 2010 StStockholm HamHamburg Sodankyla LoLocarno-Monti ToToravere Potsdam TaasTaastrup DaDaDavos gg Mean WaWageningenW HoHohenpeissenberg Poly. Mean

Global measurements

The GEBA database holds about 250,000 records The first version of the Global Energy Balance of monthly mean energy fluxes measured at Archive (GEBA) database was implemented at 1600 stations worldwide. the ETH Zurich in 1988. In 1991, the database was first made available to the global scientific community. In 1994/95, GEBA was redesigned and a large amount of data was added. The 68

Klima_S68_69_GEBA.indd 68 6.3.2008 11:13:24 Uhr Klima_S68_69_GEBA.indd 69 controlprocedures. archiveThe currently con- quality of series a to attached being portance im- great with updated, regularly is database – animportantelementindataanalysis. are integrated into instrumentation in changes of details and cy consisten- Data years. the over replaced been have instruments sites, most at addition, In and are measured using different instruments. been have values the that noted be should It bulent heatfluxes. and ation, long-wave short- radiation and tur- ables. These include, for example, global radi- of 19vari- total different a with components, balance energy various incorporates GEBA worldwide. stations 1600at measured fluxes tains 250,000 records of monthly mean energy Annual meansinW/m Global radiationat 10 database European stationsfrom theGEBA global radiation [ W/m2] 100 120 130 140 150 160 170 180 110 100 110 120 130 140 150 160 170 180 70 80 90 70 80 90 1920 1920 1920 Wa St Taas Lo St Wa 1930 Stockholm Wageningen Taastrup Locarno-Monti Stockholm W GEBA 2 as station history data 1930 1940 1940 1950 1950 1960 portant functions in climate research: (a) vali- (a) research: climate in functions portant ae rgam ( Programme mate (d) evaluating the impact of aerosols releasedaerosols of impact the evaluating (d) ing absorption of solar radiation by clouds and study- (c) models, circulation general by lated data, validating (b) surface energy fluxes simu- dating radiation products derived from satellite Importance forGCOS lead of the World Meteorological World the of lead ( Archive ance Responsibility Davos, Wageningen, Stockholm, – sites pean Euro- from come series data flux energy est from forest fires in equatorial regions. The long- Office funding will be required to maintain and from assured longer no is Continued operation of Resources required Since The data stored in Da Ho To To Ham Ho Da http://bsrn.ethz.ch/gebastatus Hohenpeissenberg Davos Toravere Hamburg ovember 1986, the Global Energy Bal- November Energy 1986,Global the 1960 1970 GEBA 1970 GEBA WCP 1980 ) has been a World Cli- World a been has ) g g GEBA serve a variety of im- poet ne the under project ) 2008 1980 at the 1990 . Swiss . ETH Organiza- Mean Sodankyla Poly. Mean Potsdam Zurich 1990 GCOS 2000

the cryosphere). (including system climate the in processes er fundamental importance in understanding oth- The years. 40 morethan covering series time with worldwide stations 380 from analysed been 1940.alreadyfore Tohave observations date, be- began measurements radiation stations, and Potsdam tific community. scien- the for accessible readily is it that sure regularly update the Council for Science ( ( tion mate Science( cated at the Institute for Atmospheric and Cli- 2000 2010 GEBA WMO energy balance components are of are components balance energy 2010 this trend has been reversed over reversed been has trend this per cent (global dimming), and that several by declined surface Earth’s 1960 and 1990 solar radiation at the between that shows analysis The years. 50 least at back going able avail- are measurements radiation cluded in the database GEBA where in- stations European 10at diation ra- global mean annual in Changes 1952 2006). (Ohmura, W/m 20 about of radiation global in increase an (Stockholm and Wageningen) show The two longest ening). data series the past 10–15 years bright- (global ), UNESCO IAC croMni A tee five these At Locarno-Monti. ) atthe GEBA ICSU and the International International the and ). The database is lo- database and to en- 2 ETH between 1922 and 1922 between Zurich. 6.3.2008 11:13:25 Uhr

69 International CENTRES 4.2 BSRN The Baseline Surface Radiation Network (BSRN) is the global baseline network for monitoring the radiation field at the Earth’s surface. Global changes in radiation fluxes can only be reliably determined on the basis of consistent, long-term, high-quality observations – hence the importance of systematic archiving of data.

Ny Alesund, Spitsbergen Barrow, Alaska, USA

260 260 255 255 2 2 250 250 W/m 245 W/m 245 240 240 235 235 1992 1994 19961997 2000 2002 1992 1994 19961997 2000 2002

Boulder, USA Payerne, Switzerland

260 260 255 255 2 2 250 250 W/m W/m 245 245 240 240 235 235 1992 1994 19961997 2000 2002 1992 1994 19961997 2000 2002

Global measurements

Baseline Surface Radiation Network (BSRN) mon- At 38 BSRN stations distributed across all cli- itoring sites. Red: operational BSRN stations; matic zones, at latitudes between 80° N and blue: planned BSRN stations. 90° S, all the components of solar and atmospheric radiation are measured. These measurements are carried out with instruments and methods providing the greatest possible accu- 70

Klima_S70_71_BSRN.indd 70 6.3.2008 11:20:43 Uhr Klima_S70_71_BSRN.indd 71 t h Wrd aito Mntrn Center Monitoring Radiation World the at future inclusion. the in participating currently not sites of number a addition, In oftheend2006). files available(as 38 stations, with more than 3400 monthly data tabase. At present, users can access data from ing from station to station) are stored in the da- other surface and upper air observations (vary- data, radiation as well As procedures.control quality of variety a undergo data the archive, ETH Atmospheric and Climate Science ( ( global The Annual meansinW/m Solar radiation at four BSRN stations 1992 −2002 poral resolution ofoneminute. racy, so that data can be collected with a tem- WRMC W/m2 W/m2 235 240 245 250 255 260 235 240 245 250 255 260 Zurich. Before being integrated into the into integrated being Before Zurich. 921994 1992 921994 1992 ), which is based at the Institute for Institute the at based is which ), BSRN esrmns r stored are measurements Ny Alesund,Spitsbergen BSRN 2 9620 2002 2000 1996 9620 2002 2000 1996 Boulder, USA are candidates for candidates are 1997 1997 IAC ) of the model simulations. In addition, local measure- The fluxes, for surface radiation of satellite products (e.g. sets can be used for calibration and validation data- global These questions. climate-related Importance forGCOS The ( Science for Council International the rological The field. Earth’sradiation the in changes global Responsibility ments can be used in the derivation of regional Climate Science ( Science Climate and Atmospheric for Institute the at archive From Resources required me Global Energy and Water Cycle Experiment search Programme ( chiving offers a unique potential for studying for potential unique a offers chiving vations and continuous quality control and ar- obser-operational global of combination The longer assured. Funding to ensure the conti- the ensure to Funding assured. longer http://bsrn.ethz.ch BSRN WCRP BSRN 2 2

2008 W/m W/m  235 240 245 250 255 260 235 240 245 250 255 260 2.5 Radiation) and of global climate global of and Radiation) 2.5 rganization ( Organization is a project of the World Climate Re- is part of the of part is is sponsored by the World Meteo- World the by sponsored is , continued operation of the of operation continued , 921994 1992 1994 1992 IAC WCRP ) at the at ) WMO Payerne, Switzerland Payerne, Barrow, Alaska, USA WCRP ) aimed at detecting 9620 2002 2000 1996 2002 2000 1996 ETH ), subprogram- UNESCO Zurich is no is Zurich 1997 1997 ICSU BSRN and ).

budget caused by natural and human factors. human and natural by caused budget radiation the in changes of recording tinuous Institute for Atmospheric and Climate Science provided as far as possible through the Swiss the through possible as far as provided GCOS ing oftheglobal ( ( of new of establishment (e.g. applied increasingly are the that ensure to made being are efforts network, baseline Since the gions oftheworld). radiation climatology.The radiation influences the development of the of development the influences significantly thus and researchplanning for le responsib- is which Group, Steering Scientific nuity of this GEWEX IAC ) at the Office. BSRN ). The ). BSRN ETH t 9 SN ttos hw n in- an show stations BSRN 19 at 1990s.Studies early the since wide world- out carried measurements BSRN by confirmed is brightening) (global mid-1980s the since served ob- trend radiation solar surface the in reversal the that indicates over the period 1992–2002. Analysis stations BSRN selected at observed radiation solar in Changes quality (Wild etal.,2005). quality (Wild air in improvements widespread to particular in but cover cloud in be attributable not only to changes period 1992–2004. This reversal may crease of 0.47 W/m GCOS stations in underrepresentedre-in stations has been designated as a GEWEX Zurich is responsible for archiv- GCOS BSRN reference archive should be programmea by run is data. monitoring principles monitoring BSRN 2 per year for the permits con- permits BSRN GCOS . The .

6.3.2008 11:20:44 Uhr

71 International Centres 4.3 W G M S The activities of the World Glacier Monitoring Service (WGMS) are of crucial importance for climate observation. As well as being among the most sensitive climate indicators, glaciers play a key role in the regional water balance and contribute to rising global sea levels associated with climate change.

-2000-2'000000

-4000-4'000000

-6000-6'000000

-8000-8'000000 Mittelwertmean of von 30 30 (27 (27 in 2005)2005) Gletschern glaciers Mittelwert von 30 (27 in 2005) Gletschern Mittelwert von 9 Gebirgsregionen Mittelwertmean of von 9 mountain9 Gebirgsregionen regions cumulative mean speciﬁc net balance e.] [mm w. -10000-10'000-10'000000000 19801980 1985 1990 1995 2000 2005

Global measurements

Observations collected by the World Glacier The WGMS manages an extremely comprehen- Monitoring Service (WGMS). Red: monitoring sive collection of data on glaciers, their char- of mass balance; green: monitoring of changes acteristics and fluctuations over time. These in glacier length; blue: glacier inventory data. regularly updated data are made available to Data from the WGMS. scientists and the public. The database currently holds more than 34,000 length change 72

Klima_S72_73_WGMS.indd 72 6.3.2008 11:32:17 Uhr Klima_S72_73_WGMS.indd 73 Mass balance for 30 glaciers worldwide 1980 −2005 and moraines. type morphological of classification and tion eleva- orientation, length, area, location, cal the world. The parameters include geographi- tion on more than 72,000 glaciers throughout cier Inventory” ( wide every 2 years; and thirdly, the “World Gla- world- glaciers selected from measurements Bulletin” ( secondly, Balance Mass “Glacier intervals; the 5-yearly at published world, the throughout glaciers in changes on data standardized ing present- series, (FoG) Glaciers” of tuations mid-20 worldwide, extending back to the mid-19 glaciers 200 from observations balance mass 3000 and glaciers 1725from measurements Cumulative meanannualnetbalanceinmmwaterequivalent arethe by published

-10000 cumulative mean speciﬁc net balance [mm w. e.] -8000 -6000 -4000 -2000 -10'000 -10'000 -8'000 -6'000 -4'000 -2'000 000 000 000 000 000 000 th 0 0 century,productsrespectively. Three 1980 0 1980 1980 GMBB WGI ), which reports mass balance Mittelwert von9Gebirgsregionen Mittelwert von9Gebirgsregionen Mittelwert von30(27in2005)Gletschern Mittelwert von30(27in2005)Gletschern Mittelwert von30(27in2005)Gletschern mean of9mountainregions mean of30(27in2005)glaciers ), which contains informa- WGMS 1985 1985 : firstly,: “Fluc- the th and 1990 1990 Analysis Services of the International Coun- International the of Services Analysis Data Geophysical and Astronomical of tion ainl olcin n pbiain f gla- of publication and collection national Zurich-based the 1986, Since Zurich. in Congress logical 6 the at Commission Glacier International the of establishment the with 1894 in initiated was worldwide variation glacier on data of collection The Importance forGCOS cil for Science ( The Responsibility Terrestrial Global the for responsible is it and data, cier responsibility for worldwide glacier monitoring continuation of the already 110-year-old Swiss dation and the University of Zurich. Thereafter, 2009 Basic funding for Resources required the by 1986 since pursued been have and in epyis ( Geophysics and Geodesy of Union International the of

ordinated glacier observations began in 1894in began observations glacier ordinated soito o Cyshrc cecs ( Sciences Cryospheric of Association OS GCOS/GT http://www.wgms.ch WGMS through the Swiss etwork for Glaciers ( Glaciers for Network is a service of the International International the of service a is WGMS IUGG FAGS/ICSU . The 1995 1995 WGMS , n o te Federa- the of and ), has coordinated the inter- WGMS National Science Foun- th is assured until March nentoa Geo- International ). Internationally co- database current- GTN-G 2000 2000 ) with- ) IACS ) The new initiatives such as the as such initiatives new ( the Global in developed were methods sensing Remote Inventory. Glacier World the of maintenance funding through the Swiss the through funding at the University of Zurich will require long-term zations ( tion programmes of major international organi- tem ( TerrestrialGlobal the to bution Sys- Observing The countries involvedinglaciermonitoring. all in correspondents national and searchers WGMS national climateobservation. inter- and national for glaciers of importance major the on based is funding for justification ment ( ment national PolarYear ( Satellite data are increasingly being used in the mass balanceseriesforSwissglaciers. ly includes 120 length change series and eight GLIMS 2005 2005 WGMS GTOS WGMS DUE , now based at the University of Zurich. ) project and are now also being used in UNEP, WMO,UNESC Land Ice Measurements from Space ) within the global climate observa- ) GlobGlacier project or the Inter- the or project GlobGlacier ) maintains contacts with local re- local with contacts maintains ws gair Slrta n Gries. and Silvretta glaciers Swiss the on data includes 2005) 2004; Haeberli, (cf. index recognized ly international- This (6). Asia Central and Europe(19) (1), America South (4), America North in are glaciers 1980.since itoredcontinuously The where mass balance has been mon- ranges mountain nine and 2005) in (27 glaciers reference 30 for ance bal- net annual mean Cumulative 2007). Datafrom theWGMS. 2007). al., et (Zemp continued has forcing climate that confirming w.e., m 9.6 mulative ice loss since 1980 to about cu- average the brings 2000–2005 period the over w.e. m 0.6 of tion The average annual thickness reduc- ae a iprat contri- important an makes IPY ) 2007/2008 ESA GCOS and Data User Data

ffice. The Office. ICSU . ). Ele- 6.3.2008 11:32:17 Uhr

73 International CENTReS 4.4 Other centres To determine state and variability of the climate system, measurements need to be globally standardized and meet the highest quality standards. With their reference instruments and regular calibration activities, international calibration centres make a vital contribution to the quality of global observation programmes.

World Radiation Center (PMOD/WRC) The Physical Meteorological Observatory World Radiometric Reference (WRR); (b) to tion measurements should be traced. The role (PMOD) was founded at Davos in 1907 to support the calibration of meteorological ra- of the WRC-IRS is to disseminate this scale to carry out research in the field of solar radio- diation instruments; (c) to promote research the worldwide community either by individu- metry and to study the effects of climate and and development in radiometry and methods al instrument calibrations at the PMOD/WRC weather conditions on humans, animals and of observation of atmospheric radiation pa- or through the creation of regional calibration plants. In 1971, the World Radiation Center rameters; and (d) to provide training for radia- centres with standards traceable to the WRC- (WRC) was established at the PMOD on the tion specialists. IRS reference. recommendation of the World Meteorological Organization (WMO). In 2006, the WMO Com- Infrared Radiometry Section (WRC-IRS) Additional facility: World Optical depth Re- mission for Instruments and Methods of Ob- The Infrared Radiometry Section was original- search and Calibration Center (WORCC) servation (CIMO) resolved that the WRC should ly established at the PMOD in 2004 on the re- The World Optical depth Research and Cali- be divided into two sections, with two addi- commendation of the CIMO and has been a bration Center (WORCC) was established at tional facilities. Section of the WRC since 2006. The WRC-IRS the PMOD/WRC in 1996. Its tasks include: (a) is establishing an interim WMO Pyrgeometer development of a radiometric reference for Solar Radiometry Section (WRC-SRS) Infrared Reference using the procedures and in- spectral radiometry to determine atmospheric The main responsibilities of the WRC-SRS Sec- strumentation that make up the World Infra- optical depth (AOD); (b) development of pro- tion are (a) to guarantee worldwide homo- red Standard Group (WISG) of pyrgeometers. cedures to ensure worldwide homogeneity of geneity of meteorological radiation meas- The Section holds the global infrared radiation AOD observations; (c) development and test- urements by maintaining the World Standard reference and thus defines the longwave infra- ing of new instrumentation and methods for Group (WSG), which is used to establish the red scale to which all longwave infrared radia- AOD; (d) implementation of a pilot network at 74

http://www.pmodwrc.ch

Klima_S74_75_IntDaten.indd 74 6.3.2008 16:45:55 Uhr Klima_S74_75_IntDaten.indd 75 was subsequently used as a as used subsequently was the from fer trans- the involved also handover This (Italy). ( Centre Research Joint mission Measurements( Radiation Ultraviolet for Centre Reference PMOD/WRC ( Center bration The meter CalibrationCenter( Additional facility: erators touseprecision filterradiometers. Activity Centres ( ation with the velopment of quality control of data, in cooper- of GAW sponsibility for this activity fromactivity this for the sponsibility ne spectroradiometer ence AOD rpa Utailt aimtr Cali- Radiometer Ultraviolet European global observatories to test measurement with precision filter radiometers; de- (e) since July since JRC GAW ECUV EUVC QA/SAC of the transportable refer- transportable the of European Ultraviolet Radio- Quality Assurance/Science ) at the at ) ) has been based at the at based been has ) 2005 ); ); and training (f) op- QASUME EUVC . It took over re- over took It . UV EuropeanCom- ) reference in reference JRC Ti unit This . European ) in Ispra in ) at the request of the of request the at goal of this Working Group is to homogenize to is GroupWorking this of goal ( Methane and Monoxide Carbon Ozone, face traceable to the designated reference. This is This reference. designated the to traceable WCC ( Centre Calibration World The World CalibrationCentre WCC-Empa UV project ( September in Europe GAW the by hosted comparison, Brewer first the submission, data of questions and issues ity audit the quality control system at global QA/SAC of tasks main The well. as measurements al ane, the scope of its activities covers addition- meth- and monoxide carbon ozone, surface on focuses it Although worldwide. facilities lished at ( Centre ity The ActivityCentre Switzerland Quality Assurance/Scientific regular system (b) and laboratories calibration central the regularintercomparisonswith and cooperation close (a) of means by achieved gional re- and national participating the for cedures mon quality assurance and quality control pro- measurementsin UV trol” Working Group is led by the by led is Group Working trol” sites, (b) to assist to (b) sites, id u a different at out ried WCC Euro-Climhist: http://www.euroclimhist.com WCC, QA/SAC:http://www.empa.ch/gaw radiation over radiation GAW s o nue ht esrmns car- measurements that ensure to is einl rwr airto Centre Calibration Brewer Regional - UV mpa) was Empa) established at ong-term Long-term changes and climatology of Switzerland are (a) to support and support to (a) are Switzerland Empa in monitoringnetworks. Quality Assurance/Scientific Activ- Assurance/Scientific Quality QA/SAC 2000 urope), the “Quality Con- “Quality the Europe), GAW Switzerland) was estab- was Switzerland) urope by defining com- defining Europeby GAW 2005 WMO and is one of four such sites with data qual- data with sites . In the In . ttos r fully are stations . The goal of the of goal The . WCC Empa in 1996 EUVC COST-726 ) for Sur- for ) GAW . The .

data seriesfor tivities ensure the evaluability long-term of the ac- these know-how, technical operators’ ing improvingas well increas-As and quality data completed 44 audits at 18 stations worldwide. measurement dataandcontactinformation. available on metadata characteristics, station vides on-site training. To date, the Todate, training. on-site vides pro- and problems technical of event the in global stations. In addition, at the audits performance and ( Centre of Competence in Research on Climate the Foundation, Science National Swiss the from funding through 2009 until of continuation The the in processedwere pre-1500 from observations dividual in- 35,000 around addition, In form. digital lion records, of which 620,000 are available in mil- 1.2than more holds currently database 14the on and Switzerland of history climate the of analysis for resource valuable a is database weather.The of perceptions on reportsas well as disasters, natural of impacts freezing,cover,river snow the and phenology on data and reports weather measurements, instrumental early of records including Bern, of University the at History of Institute at the developed database a is Euro-Climhist Euro-Climhist GAW the on information integrating for application tion System ( the of operation and One major ongoing activity is the development scientific partnerships(twinning). and workshops training, through countries developing in building capacity support to (c) to promote the use of use the promote to (c) NCCR measurement programme. This includes Climate) andtheUniversityofBern. Climate) th and 15and GAWSIS GCOS th century. Altogether the Altogether century. . ), an interactive database rCihs i assured is EuroClimhist GAW EU WCC Millennium project. Millennium GAW Station Informa- Station urope, focusing Europe, offers assistance data, and (d) (d) and data, WCC National Europe GAW has

6.3.2008 11:45:40 Uhr

75 International CENTRES 5.0 Observations outside Switzerland

Klima_S76_79_Ausland.indd 76 6.3.2008 12:02:42 Uhr Klima_S76_79_Ausland.indd 77 Introduction is part of the ten limited technical and financial resources financial and technical limited ten ened thaninSwitzerlandasaresult oftheof- threat- more is observations of continuation in developing countries. requiredarealso series time continuous term, tribution of climate-related observations, long- dis- spatial appropriate an ensure to order In the validation of satellite data. in role key a play tropics the in profiles ozone concentrations. ozone fluencing in- processes dynamic and chemical the ning determi- in importance fundamental of are ent to determine ozone trends. Ozone profiles suffici-not profilesis tropicalozone of verage ural and human factors, the current spatial co- these regions are influenced by numerous nat- ly,in concentrations ozone atmospheric while First- tropics? ozone the denser in network a measurement for need a there is Why WMO under the Swiss) logy and Climatology (Meteo Meteoro- of Office Federal the by supported began. ject pro- the since standards predefined to ing accord- continuously out carried been have in station ozone. tropospheric tropical on data ozonesonde balloon-borne consistent produce to designed is Center, Flight Space the by coordinated is which ( OZonesondes ( Programme the direction of the ozone soundings have been carried out under orological At the aerological station of the Kenyan Mete- Ozone (Kenya) available. gramme. Programme ( http://croc.gsfc.nasa.gov/shadoz/ Global ioi wel ooe soundings ozone weekly Nairobi, prmn ( Department hese observations are financially are observations These UNEP outhern Southern Hemisphere UNDP Atmosphere SHADOZ ) since 1 May WMO ) and the and ) In these countries, the , the ) network. ) KMD W atch ( atch UN UN NASA A case in point 1996 in )

Development Environment t the At n addition, In G ADditional Goddard SHADOZ AW Nairobi.html . Nairobi, This site ) pro- ) KMD ,

ments are submitted to the international international the to submitted are ments measure- the before Payerne in MeteoSwiss the at performed processingis controland quality el fromoperation sonde lev- first MeteoSwiss. A ozone- on training receive to continues and local The of ping panded asfarpossible. variables in developing countries should be ex- climate essential of observation the involving support for national and regional programmes exhaustive. means no by is list the tions. from support financial and/or technical by possible made are below cribed des- countries foreign in observations The when observationsbegan. 1996,May to i.e. years, 10than more back going series reliable and continuous a offers ment of the data, the systems on site. measurement ozone operational various the of quality the assure to and training provide to station the visit members staff MeteoSwiss complementary measurements. bution measured by radiosonde are important distri- ozone vertical and instrument Dobson meter. refurbished the in performed been have ments In addition, since May 2005, parallel measure- of satelliteobservations. validation and calibration the resourcefor tial Center.Flight Space SHADOZ is the validation of the new of ozoneprofile datainCentralAfrica. ported by MeteoSwiss was the primary source 2004 Spectrometer ( number of examples are given, but given, are examples of number A KMD e zn clm maue b the by measured column ozone The . Here, the Here, . data centre at the at centre data KMD , a second level is carried out by out carried is level second a , According to the latest assess- em in team bo #8 spectrophoto- #18 Dobson TOMS KMD hese data are an essen- an are data These KMD

) data in the summer airobi station sup- station Nairobi ozone station now T ioi received Nairobi otal Ozone Map- NASA Each year, two is institu- Swiss airobi with Nairobi Goddard n future, In 12.3.2008 16:32:47 Uhr

77 Observations outside Switzerland Trace gases (Kenya, Indonesia, Algeria) The establishment of the global GAW sta- are particularly vulnerable to the effects of tions Mount Kenya-Nairobi (Kenya), Bukit climate change as a result of political, eco- Koto Tabang (Sumatra, Indonesia) and Taman- nomic and social structures. At most of rasset Assekrem (southern Sahara, Algeria) these stations, infrastructure and instrumen- was initiated in the early 1990s by the WMO tation were completed in the mid-1990s. with support from the Global Environment After providing initial training for the sta- Facility (UNDP, UNEP, World Bank) to fill evi- tion operators and operational support, the dent gaps in the global surface observation countries involved in setting up these sta- network. These gaps were and are still located tions rapidly withdrew following the early suc- mainly in countries south of the equator, which cesses.

Surface ozone at three global GAW stations 1997 − 2007 Concentration expressed as ozone volume mixing ratio in parts per billion by volume (ppbv)

Surface ozone measured at three AssekremBukit Koto Tabang Mt. Kenya southern Saharan (Assekrem, Al- Mt.Assekrem Kenya Bukit Koto Tabang geria, red) or equatorial global 60 GAW stations (Mt. Kenya, Kenya, blue; Bukit Koto Tabang, Indone- sia, green). On account of their elevation, Assekrem (2770 m a.s.l.) 40 and Mt. Kenya (3678 m a.s.l.) show higher ozone concentrations than

ozone [ppbv] Bukit Koto Tabang (964 m a.s.l.). The varying mean concentrations reflect 20 the complex interactions between ozone formation and destruction. Data: WDCGG, QA/SAC Switzer- land. 0

1998 2000 2002 2004 2006

Since the beginning of the 21st century, Empa and are thus particularly valuable and worthy has been responsible for two GAW functions of protection. They are ideally complemented co-financed by MeteoSwiss – the Quality by the NOAA flask sampling programme. None- Assurance/Scientific Activity Centre (QA/SAC theless, there is an urgent need to supplement Switzerland) and the World Calibration Centre and independently validate weekly sampling for Surface Ozone, Carbon Monoxide and with continuous measurements of the green- Methane (WCC-Empa) ( 4.4 Other centres). house gases methane and nitrous oxide, and In their efforts to ensure the continuation of of hydrogen. these observations, the institutions focus in The importance of these stations for GCOS particular on quality assurance, training of lies primarily in their geographical location and station operators, replacement of instruments relatively sound infrastructure. They permit and scientific support. unique continuous atmospheric measurements The surface ozone and carbon monoxide – also allowing the determination of trends in measurements from these stations are the only these regions – which would hardly be possible continuous series available for the southern with satellite-based observations alone. Sahara, equatorial Africa and equatorial Asia

http://www.empa.ch/gaw/gawsis

Klima_S76_79_Ausland.indd 78 12.3.2008 16:33:09 Uhr Klima_S76_79_Ausland.indd 79 ong-term (red), recent (blue) and interrupted (green) dataseries andinterrupted(green) recent (blue) (red), long-term Mass balanceobservationsworldwide balance series and 50 shorter series, around series, shorter 50 and series mass balance continuous long-term 30 as well as programmes. monitoring climate most important indicators used in international the of one thus is and year a in conditions ic delayed reaction totheprevailing atmospher- un- and direct the is balance mass Glacier Glaciers ntae i Clmi and Columbia in initiated the field. the in glaciologists for training and control quality data ards, in with ance compli- of assurance including countries, ing develop- in particularly observations, glacier the Monitoring lengths. various of periods covering available, are series interrupted 120 empa. through cooperation between Meteoswiss and and nesia Kenya, in monoxide) carbon ozone, (surface gases trace of measurements the component oftheswiss international the through assured is (Kenya) in soundings ozone the of Funding Resources required pansion of the measurement programme, as programme, measurement the of pansion series capacity (instrumentation, building). tional funding will be required to maintain the http://www.wgms.ch , new observations were recently were observations new wGMs, w GMs in the medium term (from service ( also offers technical support for support technical offers also gra r ol prl assured partly only are algeria ternational methods and stand- and methods ternational w GMs G w aw ) at the the new ith support from support ith programme. w 2010 university of zealand. orld Glacier orld w orldwide, nairobi ), addi- indo- ex- in glacier monitoringnetwork. the in underrepresented currently are gions re- two these as hemisphere, southern the and tropics the in ranges mountain glaciated dition, newobservationsare beinginitiatedin financial reasons. ed for political and/or valuable series, most of which were discontinu- and the resumption of a number of particularly referencelong-term series 30 the of tinuation zurich supports and actively promotes the con- in underrepresented regions bythe the initiation of new mass balance observations and series long-term discontinued of number reference30 the resumptionthe a glaciers, of continuation of mass balance measurements at the ensure to required is funding additional call foradditionalfinancialresources. also would hydrogen) hexafluoride, sodium for vance rele- of substances other cover to desired, is Himalayas. former in measurements are reactivated be to series valuable the cy.among Foremost poli- financial of reasons for risk at are which in series reference of continuation securethe to made effortsarebeing addition, soviet republics, China, Kenya and the GCOs ciaooia ad hydrological and climatological a From (green). glaciers 120around ed series of various lengths exist for Discontinu- 2000–2005. period the for (blue) glaciers 80 about for le bal- availab- are measurements mass ance yearly addition, In in glaciers 9 (red) mountain ranges. 30 for available are onwards 1980 worldwide. Continuous series from observations balance mass Glacier derrepresented regions. tivated as rapidly as possible in un- vation programmes should be reac- number of these interrupted obser- a that important is it perspective, mtae ntos oxide, nitrous (methane, ussia, the russia, w GMs alaska, in ad- . 6.3.2008 16:59:42 Uhr

79 ObservatiOns Outside switzerland 6.0Conclusions and outlook

Klima_S80_83_Schlussfolgerung.indd 80 6.3.2008 13:31:30 Uhr Klima_S80_83_Schlussfolgerung.indd 81 tion. observations required by the Climate Conven- to be taken into account. into taken be to also are features regional distinctive level, nal ticular attention is to be paid to key climate key to paid be to is attention ticular For the implementation of [...]» regions; Pro- gramme and to similar initiatives in other Africa ClimDev the of mentation imple- the to contributing by and Plans, and systems within the framework of and terrestrial climate observing networks oceanic related and hydrological spheric, climate variables –, essential pollen, isotopes the and pheno- to addition in – report this In the in variables a comprehensive picture of climate monitoring provide here presented series data long-term are at risk or the legal basis is inadequate. series time whereparticular, cases identifies it in measured variables climate essential the all of observations systematic of This report gives an account of the current state Conclusions projects in the ten the in projects implementing by services climate of sion relevant data, and to enhance their provi- climate- acquire to capacity their improve to strengthen their observing networks, to Members country developing Toassist 2. and insupportofuserneeds; 1. «[...] member statesare urged: at the Fifteenth national efforts. global system is crucially dependent on strong ( Plan Climate Global the of ponent GCOS Switzerland). ( system observing climate national the of operation future the secure to efforts in tem ( tem witzerland today.Switzerland o teghn hi ntoa atmo national their strengthen To ccording to the to According GCOS WMO

izrad s n motn com- important an is Switzerland ), which is covering the systematic the covering is which ), , 2004 WMO lps (e.g. glacier monitoring). monitoring). glacier (e.g. Alps In Resolution adopted 3.2.3/1 ), the development of the of development the ), GCOS Congress ( he report thus informs thus report The GCOS In GCOS Regional Action Regional witzerland, par-Switzerland,

Implementation Switzerland. Observing WMO at the natio- , 2007 GCOS GCOS Sys- The In ), -

tinued operation of two data centres ( centres data two of operation tinued ssessments of future climate change remain change climate future of Assessments from continuous, long-term, high-quality data obtained already insights the illustrate results and context of these time series. ulse Fourth published recentlythe as such studies scientific for tions observa- systematic of importance major the identified. are risks le tions of the time series are assessed and possib- opera- future fo prospects the Finally, series. series for of the legal basis, the importance of long-term time series are at risk. significant extent what to indicates and land the type of observations carried out in essential climate variables, this report describes portant variables be continued. For each of the im- most the for series data long-term isting data base, and it is therefore essential that ex- research activities require a high-quality climate Relevant uncertainties. numerous to subject global sidered as essential climate variables within the bles for varia- climate important as defined were logy to data quality.data to and observations of standardization global the to contribution vital a make centres tion calibra- and data international Switzerland’s legal basisshouldbeestablished. funding. for requests accompany to elaborated be should networks monitoring these of future the for plans variables, six these For ensured. not is funding – phenology and permafrost glaciers, cover, snow lakes, dioxide, carbon – variables certain For permafrost). glaciers, tirely lacking for cryosphere observations (snow, climate monitoring. related to the relevance of the observations for variables. However, this legal basis is often un- the of many for exists basis legal a 3), and 2 In the case of long T in summarized are analysis the of results The able 3, with at-risk serieshighlightedinred. able 3,withat-risk GCOS Switzerland. GCOS te ae ie a appropriate an time, same the At framework. and international significance and international s shown in shown As Swiss time series (Chapters IPCC A legal basis is almost en- These should also be con- An account is also given ll the results underline results the All

ssmn Report. Assessment T able 3, the con- the 3, able The scientific Switzer- GEBA , 6.3.2008 16:56:56 Uhr

81 Conclusions and outlook Essential climate variable Legal basis Responsible institution(s) Funding

Swiss time series

2.1 air temperature Yes MeteoSwiss Assured

2.2 Precipitation Yes MeteoSwiss Assured

2.3 air pressure Yes MeteoSwiss Assured

2.4 sunshine duration Yes MeteoSwiss Assured

2.5 Radiation Yes MeteoSwiss Assured

2.6 Clouds Yes MeteoSwiss Assured

2.7 Water vapour Yes MeteoSwiss, University of Bern Assured

2.8 ozone Yes MeteoSwiss Assured

2.9 Carbon dioxide Yes University of Bern Not assured

2.10 Greenhouse gases Yes Empa, FOEN Assured

2.11 air pollutants Yes Empa, FOEN Assured

2.12 aerosols Yes MeteoSwiss Assured

2.13 Pollen Yes MeteoSwiss Assured

3.1 River discharge Yes FOEN Assured

3.2 lakes Yes FOEN, Eawag, cantons Not fully assured

3.3 Groundwater Yes FOEN, cantons Assured

3.4 Water use Yes FOAG, FOEN Assured

3.5 isotopes Yes FOEN, University of Bern Assured

3.6 Snow cover Partly MeteoSwiss, WSL/SLF, private companies Not fully assured

3.7 Glaciers No EKK, ETHZ, University of Zurich Not assured

3.8 Permafrost No PERMOS (FOEN, MeteoSwiss, SCNAT) Not assured (from 2011)

3.9 land use Yes FSO Assured

3.10 Forest ecosystem Yes FOEN, WSL Assured

3.11 Forest fires Yes FOEN, WSL Assured

3.12 Phenology Yes MeteoSwiss Not fully assured

International centres

4.1 GEBA – ETHZ Not assured (from 2008)

4.2 BSRN – ETHZ Not assured (from 2008)

4.3 WGMS – University of Zurich Not assured (from 2009)

Assured, except for 4.4 other centres – PMOD/WRC, Empa, University of Bern Euro-Climhist (from 2010)

Observations outside Switzerland

5. observations outside Assured for ozone, trace gases; – MeteoSwiss, Empa, University of Zurich Switzerland not assured for glaciers

Table 3: Overview of essential climate variables, the legal basis and institution(s) responsible for monitoring, and the availability of funding. Time series and data centres whose future is at risk are shown in red.

Klima_S80_83_Schlussfolgerung.indd 82 6.3.2008 13:31:30 Uhr BSRN) is at risk in the immediate future, Technology transfer and local training are and that of one other centre (WGMS) is important means of enhancing the quality of threatened by insufficient funding in the near climate-related observations abroad, especially future. Since all three centres have a long in developing and emerging countries. As pre- tradition and are nationally and internationally sented in Chapter 5, the observations carried respected, action required to secure their future out by Swiss institutions abroad cover the fol- operation (including funding) should be initi- lowing climate variables: ozone (Kenya), trace ated as soon as possible. The globally unique cli- gases (Algeria, Kenya, Indonesia) and glaciers mate history database EuroClimhist lacks fund- (worldwide). In the future, additional finan- ing commitment from 2010 on, and should also cial resources will be required in particular for be preserved. selected glacier observations abroad.

Outlook The continuity of the most important Swiss Switzerland can play a leading role. In the climatological time series should be ensured future, measurements of many climate vari- for the future. The Swiss GCOS Office at the ables will increasingly involve the use of inte- Federal Office of Meteorology and Climato- grated systems, i.e. synchronous observations logy MeteoSwiss is therefore seeking to pro- by a combination of systems (surface, in situ, tect the long-term series of essential cli- airborne, satellite-based). High priority should mate variables that are at risk. In addition, to be attributed to adequate calibration and ensure that climate signals or artificial inhomo- validation with existing time series, and also to geneities can be distinguished from systematic the continuity of observations. biases, continued and careful attention should be paid to the GCOS Climate Monitoring Prin- The set of essential climate variables is not ciples (Table 1). Aspects deserving special static. In autumn 2008, each Party to the Cli-

attention within the Swiss GCOS Office frame- mate Convention will be required to prepare an CONCLUSIONS AND OUTLOOK work include metadata, quality assurance and updated national report on systematic obser- data archival. vations. These national reports, together with the Fourth IPCC Assessment Report, will pro- In the future, improved climatological analy- vide the basis for a review of the adequacy ses can be carried out using long-term data of the essential climate variables. Accordingly, series from surface- and satellite-based remote additional variables can be expected to be sensing systems. These technologies make it included in the national climate observing possible to fill gaps in global climate observa- system at a later date. tions arising from a lack of appropriate instruments or measurement methods. Satellite In addition, assessments of several climate data are particularly suitable for the produc- variables (i.e. integrated assessments) will tion of global datasets for a number of essen- increasingly be promoted by the Swiss GCOS tial climate variables that cannot be obtained Office. The identification of synergies in the otherwise (WMO, 2006). However, in the ana- monitoring networks should consequently lysis of satellite data, high-quality surface and help to optimize climate observations and to in situ observations remain of central impor- improve our understanding of the climate tance for calibration and validation. In this area, system as a whole. using the observations described in this report,

Klima_S80_83_Schlussfolgerung.indd 83 6.3.2008 16:57:21 Uhr Authors and Reviewers

Andreas Asch Federal Office of Meteorology and Climatology MeteoSwiss

Urs Baltensperger Paul Scherrer Institute PSI

Martin Barben Federal Office for the Environment FOEN

Andreas Bauder ETH Zurich, VAW

Michael Begert Federal Office of Meteorology and Climatology MeteoSwiss

Stefan Brönnimann ETH Zurich, Institute for Atmospheric and Climate Science IAC

Brigitte Buchmann Empa

Bertrand Calpini Federal Office of Meteorology and Climatology MeteoSwiss

Martine Collaud Coen Federal Office of Meteorology and Climatology MeteoSwiss

Marco Conedera WSL Birmensdorf

Claudio Defila Federal Office of Meteorology and Climatology MeteoSwiss

Matthias Dobbertin WSL Birmensdorf

Bruno Dürr Federal Office of Meteorology and Climatology MeteoSwiss

Paul Filliger Federal Office for the Environment FOEN

Christoph Frei Federal Office of Meteorology and Climatology MeteoSwiss

Martin Funk ETH Zurich, VAW

Gianmario Galli Federal Office of Meteorology and Climatology MeteoSwiss

Regula Gehrig Federal Office of Meteorology and Climatology MeteoSwiss

Elisabeth Graf Pannatier WSL Birmensdorf

Wilfried Haeberli University of Zurich, Department of Geography

Harrie-Jan Hendricks Franssen ETH Zurich, Institute of Environmental Engineering IFU

Martin Hölzle University of Zurich, Department of Geography

Christoph Hüglin Empa

Rainer Humbel Federal Statistical Office FSO

Pierre Jeannet Federal Office of Meteorology and Climatology MeteoSwiss

Niklaus Kämpfer University of Bern, Institute of Applied Physics IAP

Giovanni Kappenberger Federal Office of Meteorology and Climatology MeteoSwiss

Daniel Keuerleber-Burk Federal Office of Meteorology and Climatology MeteoSwiss

Jörg Klausen Empa

Thomas Konzelmann Federal Office of Meteorology and Climatology MeteoSwiss

Ronald Kozel Federal Office for the Environment FOEN

Norbert Kräuchi WSL Birmensdorf

Christoph Kull OcCC

Markus Leuenberger University of Bern, Physics Institute

David Livingstone Eawag

Christoph Marty WSL Davos – SLF

Christian Mätzler University of Bern, Institute of Applied Physics IAP 84

Klima_S84_89_Autoren_Referenzen.indd 84 6.3.2008 14:13:30 Uhr Ralf Meerkötter DLR, Institute for Atmospheric Physics

Gerhard Müller Federal Office of Meteorology and Climatology MeteoSwiss

Urs Neu ProClim

Jeannette Nötzli University of Zurich, Department of Geography

Urs Nyffeler Federal Office for the Environment FOEN

Frank Paul University of Zurich, Department of Geography

Annette Peter Federal Office of Meteorology and Climatology MeteoSwiss

Martin Pfaundler Federal Office for the Environment FOEN

Rolf Philipona Federal Office of Meteorology and Climatology MeteoSwiss

Stefan Reimann Empa

Kathy Riklin OcCC

Christoph Ritz ProClim

Mario Rohrer Meteodat GmbH

Ferdinand Schanz University of Zurich, Institute of Plant Biology

Andreas Schellenberger Federal Office for the Environment FOEN A uthors and reviewers

Simon Scherrer National Center for Atmospheric Research NCAR

Andreas Schild Federal Office for Agriculture FOAG

Werner Schmutz PMOD/WRC

Gustav Schneiter WSL Birmensdorf

Marc Schürch Federal Office for the Environment FOEN

Manfred Schwarb Meteodat GmbH

Martin Steinbacher Empa

Urs Steinegger Meteodat GmbH

Thomas Stocker University of Bern, Physics Institute

René Stübi Federal Office of Meteorology and Climatology MeteoSwiss

Pierre Viatte Federal Office of Meteorology and Climatology MeteoSwiss

Daniel Vonder Mühll ETH Zurich, SystemsX.ch

Laurent Vuilleumier Federal Office of Meteorology and Climatology MeteoSwiss

Ruedi Weber Federal Office for the Environment FOEN

Christoph Wehrli PMOD/WRC

Felix Weibel Federal Statistical Office FSO

Martin Wild ETH Zurich, Institute for Atmospheric and Climate Science IAC

Thomas Wohlgemuth WSL Birmensdorf

Christian Wüthrich University of Bern, Institute of Geography

Christoph Zellweger Empa

Michael Zemp University of Zurich, Department of Geography

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Cover photos Imagepoint.biz Courtesy of EUMETSAT, Archive FU Berlin

Contents Nando Foppa, MeteoSwiss; Gabriela Seiz, MeteoSwiss; Simon Scherrer; PMOD/WRC; Australian Government, Department of Foreign Affairs and Trade; Nando Foppa, MeteoSwiss

1.0 Introduction Nando Foppa, MeteoSwiss 2.1 Air temperature PIXELIO (www.pixelio.de), ID: 94’712 2.2 Precipitation PIXELIO (www.pixelio.de), ID: 120’390 2.3 Air pressure Arthur Kunz, MeteoSwiss 2.4 Sunshine duration Arthur Kunz, MeteoSwiss 2.5 Radiation Nando Foppa, MeteoSwiss 2.6 Clouds Gabriela Seiz, MeteoSwiss 2.7 Water vapour Nando Foppa, MeteoSwiss 2.8 Ozone René Stübi, MeteoSwiss 2.9 Carbon dioxide Gerla Brakkee 2.10 Greenhouse gases Nando Foppa, MeteoSwiss 2.11 Air pollutants Christoph Hüglin, Empa 2.12 Aerosols Christoph Hüglin, Empa 2.13 Pollen Regula Gehrig, MeteoSwiss 3.1 River discharge Nando Foppa, MeteoSwiss 3.2 Lakes Simon Scherrer 3.3 Groundwater Marc Schürch, FOEN 3.4 Water use PIXELIO (pixelio.de), ID: 139’483 3.5 Isotopes Marc Schürch, FOEN 3.6 Snow cover Christoph Marty, SLF 3.7 Glaciers Christian Theler, Archive VAW/ETHZ 3.8 Permafrost Andreas Asch, MeteoSwiss 3.9 Land use swissimage © 2007 swisstopo (BA071626, JD072726) map: Land Use Statistics (2007, FSO) 3.10 Forest ecosystem Simon Scherrer 3.11 Forest fires Marco Conedera, WSL 3.12 Phenology Nando Foppa, MeteoSwiss 4.1 GEBA PIXELIO (www.pixelio.de), ID: 166’087 4.2 BSRN Laurent Vuilleumier, MeteoSwiss 4.3 WGMS NASA /GSFC/METI /ERSDAC/JAROS, and U.S./Japan ASTER Science Team 4.4 Other centres PMOD/WRC 5.0 Observations outside Switzerland Jörg Klausen, Christoph Zellweger, Empa 6.0 Conclusions and outlook Nando Foppa, MeteoSwiss

Klima_S90_Bildnachweis.indd 90 12.3.2008 16:03:14 Uhr Abbreviations

Klima_S0000_Umschlag.indd 3 6.3.2008 14:38:45 Uhr