Progress to Applications in the User Community

A proposal in response to ESA-ESTEC Invitation to Tender “Operational Atmospheric Chemistry Monitoring Missions” AO/1-4273/02/NL/GS. Date of Submission: 31 January 2003

CAPACITY

Composition of the Atmosphere: Progress to Applications in the user CommunITY

VOLUME 1 TECHNICAL PROPOSAL CAPACITY AO/1-4273/02/NL/GS Technical Proposal

2 CAPACITY AO/1-4273/02/NL/GS Technical Proposal

TABLE OF CONTENTS

EXECUTIVE SUMMARY List of Acronyms Selection of relevant websites 1 Introduction...... 1-6

1.1 BACKGROUND...... 1-6 1.2 STUDY OBJECTIVES...... 1-6 2 Study approach and study logic...... 2-8

2.1 STUDY APPROACH...... 2-8 2.2 STUDY LOGIC...... 2-8 3 User communities and application requirements...... 3-10

3.1 ATMOSPHERIC COMPOSITION: THE MAIN ISSUES...... 3-10 3.2 SPACE MISSION OBJECTIVES...... 3-11 3.3 PROTOCOL MONITORING AND POLICY SUPPORT...... 3-11 3.4 AIR QUALITY MONITORING AND POLICY SUPPORT...... 3-13 3.5 LONG-TERM SCIENCE ISSUES AND CLIMATE MONITORING...... 3-15 3.6 FORECAST CAPACITY...... 3-15 3.7 USER REQUIREMENTS...... 3-16 4 Observational requirements per target application...... 4-20

4.1 DERIVATION OF LEVEL 2/3 DATA REQUIREMENTS...... 4-20 4.2 ASSESSMENT OF CAPABILITIES OF EXISTING & PLANNED SPACE MISSIONS AND GROUND NETWORKS...... 4-21 4.3 INTEGRATED OBSERVING SYSTEMS PER TARGET APPLICATION...... 4-23 5 Derivation of individual and combined mission concepts...... 5-25

5.1 INSTRUMENT PERFORMANCE AND REQUIREMENTS- GEO...... 5-25 5.2 INSTRUMENT PERFORMANCE AND REQUIREMENTS- LEO...... 5-26 5.3 DERIVATION OF MISSION CONCEPTS – SPACE SEGMENT...... 5-27 5.4 DERIVATION OF MISSION CONCEPTS – GROUND SEGMENT...... 5-28 5.5 CONCLUSIONS AND RECOMMENDATIONS...... 5-29 6 Related Projects...... 6-30

EXECUTIVE SUMMARY

The subject of this proposal CAPACITY to ESA refers to Operational Atmospheric Chemistry Monitoring Missions. Here operational is meant in the sense that a reliable service of specified information products can be established that satisfies user needs. Monitoring is meant in the sense that long-term continuity and consistency in the quality of the information products can be achieved. The objectives are:  To consult with user communities identified and involved in this consortium as a partner, to develop high level information requirements and the form in which the user wants this information to be presented and delivered.  To identify and prioritise mission objectives.  To derive mission data requirements from the high level user information requirements and iterate these with the user communities targeted.  To set these requirements against observation systems available or approved for the future. Here integrated observation systems are considered to be based on the integration of in-situ and space data, employing data assimilation techniques.  To identify missing information products or products of insufficient quality.  To define a global observation system that would satisfy user requirements The time frame of this operational system is projected to cover the period 2010 to 2020 concurrent with the operational satellites MetOp and NPOESS.

In order to address these objectives a large European consortium has been formed consisting of approximately 30 partners from 9 ESA countries (F, D, UK, I, SW, N, DK, B, NL). Six application areas are identified out of which the following four missions are derived:  Protocol Monitoring (Montreal and Kyoto) and Policy Support  Air Quality Monitoring and Policy Support (CLRTAP)  Long Term Science Issues and Climate Monitoring  Forecast Capacity Requirements will be addressed by relevant user organisations building upon heritage of previous and ongoing studies. For Protocol Monitoring this involves as a partner the WMO, NILU in its connection to the EMEP emission data base, and JRC-IES in relation to EC DG Environment. For Air Quality this involves RIVM and NILU in relation to the EEA Topic Centre for Air Quality and Climate Change, JRC-IES in relation to EC air quality directives, ADEME a French national environment and energy agency, TNO a Dutch organisation for aerosol air pollution. Long-term science issues will be addressed by partners involved in international atmospheric chemistry projects. MPI-Mainz representing IGBP-IGAC, DLR representing chemistry-climate interaction, ETH Zurich representing WCRP-SPARC, University Heidelberg representing TROPOSAT, CNR-ISAC representing the EC 6th FP atmospheric chemistry project ACCENT. Forecast capacity is addressed by meteorological institutes KNMI, Meteo-France and DMI representing EUMETNET and by EUROCONTROL for air traffic management.

In the derivation of data level 2/3 requirements from high level requirements the consortium relies on a large group of modellers using satellite data, and of space research institutes with expertise in retrieval and calibration/validation of satellite data as well as Industry with experience in building space instrumentation. The project will be led by the Royal Netherlands Meteorological Institute (KNMI) supported by a core group of Space Research organisations RAL, Univ-Leicester and Univ-Bremen, and Industry Astrium and Alcatel. These organisations will be supported in turn by a large consortium covering most interested parties in Europe, including LSCE Paris, Univ Oslo, USTL-LOA Lille, CNRS-LISA Paris, FZK-IMK Karlsruhe, CNRS-LMPA Paris, CNRS-SA Paris, CNRS-LPPM Paris, Noveltis Paris, CEA Paris, SRON Utrecht, BIRA-IASB Brussels, CNR-IFAC Florence.

The project will be concluded and recommendations formulated on the basis of consensus.

LIST OF ACRONYMS

ATSR Along Track Scanning Radiometer CAPACITY Composition of the Atmosphere: Progress to Applications in the user CommunITY CEOS Committee on Earth Observation Satellites CLRTAP Convention on Long-Range Trans-boundary Air Pollution DOAS Differential Optical Absorption Spectrometry EC European Commission ENVISAT Environmental Satellite ESA European Space Agency EUMETSAT European organisation for the exploitation of Meteorological Satellites GATO Global ATmospheric Observations GCOM Greenhouse Gas Monitoring Satellite GMES Global Monitoring for the Environment and Security GOME Global Ozone Monitoring Instrument GOMOS Global Ozone Monitoring by Occultation of Stars IASI Infrared Atmospheric Sounding Interferometer IGAC International Global Atmospheric Chemistry IGBP International Geosphere-Biosphere Program IGOS Integrated Global Observing Strategy IPCC Inter-governmental Panel on Climate Change METEOSAT Meteorological Satellite MetOp Meteorological Operational Polar satellites of Eumetsat MIPAS Michelson Interferometer for Passive Atmospheric Sounding MSG Meteosat Second Generation NASA National Aeronautics and Space Administration NASDA National Space Development Agency of Japan NDSC Network for the Detection of Stratospheric Change NPOESS National Polar-orbiting Operational Environmental Satellite System NRT Near-real time OMI Ozone Monitoring Instrument OMPS Ozone Mapping and Profiling Suite PROMOTE PROtocal MoniTOring for the GMES Service Element SBUV Solar Backscatter UltraViolet radiometer SCIAMACHY SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY SODA Studies on Ozone Distributions based on Assimilated satellite measurements TEMIS Tropospheric Emission Monitoring Internet Service TOMS Total Ozone Mapping Spectrometer TROC Tropospheric Chemistry and Climate UARS Upper Atmosphere Research Satellite WCRP World Climate Research Program WMO World Meteorological Organization

SELECTION OF RELEVANT WEB SITES

AERONET http://aeronet.gsfc.nasa.gov/ BIRA-IASB http://www.oma.be/BIRA-IASB/ CAFÉ http://europa.eu.int/comm/environment/air/ CLRTAP http://www.unece.org/env/lrtap/ DUP http://dup.esrin.esa.int/ EMEP http://www.emep.int/ ENVISAT http://envisat.esa.int/ EOS AURA http://eos-chem.gsfc.nasa.gov/ ERS http://earth.esa.int/ers/ ESA http://www.esa.int/ ESRIN http://www.esrin.esa.int/ GATO http://www.ozone-sec.ch.cam.ac.uk/Clusters/Gato/ GOFAP http://www.knmi.nl/gome_fd/ GOME http://earth.esa.int/eeo4.96 GOME-Bremen http://www-iup.physik.uni-bremen.de/gome/ IGAC http://www.igac.unh.edu/ KNMI http://www.knmi.nl/ Meteo-France http://www.meteo.fr/ NADIR DATABASE at NILU http://www.nilu.no/projects/nadir/ SCIAMACHY http://envisat.estec.esa.nl/instruments/sciamachy/ Sciamachy-Bremen http://www-iup.physik.uni-bremen.de/sciamachy/ Sciamachy Validation http://www.knmi.nl/sciamachy-validation/ SODA http://www.knmi.nl/soda/ SPARC http://www.aero.jussieu.fr/~sparc/ TEMIS http://www.temis.nl/ TOMS http://jwocky.gsfc.nasa.gov/ TROPOSAT http://troposat.iup.uni-heidelberg.de/ WMO ozone bulletins http://www.wmo.ch/web/arep/ozone.html

1 INTRODUCTION

1.1 BACKGROUND

In recent years there have been a number of initiatives aimed at creating a global observation system for the environment and climate. The IGOS (Integrated Global Observing Strategy) intends to improve integration of space-based and in-situ systems for global observation of the Earth. The IGOS partnership consists of a number of international organisations representing both the user side (IGBP International Geosphere-Biosphere Programme, and WRCP World Climate Research Programme) and the satellite side (CEOS Committee on Earth Observation Satellites) as well as an international group of funding agencies for global change research. IGOS includes several themes covering the global water cycle, oceans, the carbon cycle and recently atmospheric chemistry.

On a European scale the joint EC (European Commission) and the ESA (European Space Agency) initiative for GMES (Global Monitoring for the Environment and Security) has similar objectives. It aims at making better use of existing and planned global observation systems and at identifying gaps in information. It is directed at assembling a coherent and long term functioning system to produce policy relevant information. Also here the initiative covers a number of themes including the atmosphere. The GMES-GATO project is of relevance here as it is directed at developing a strategy for global atmospheric observations in GMES, covering an integrated observation system, database issues and a strategy for the post ENVISAT era..

These initiatives echo the need for more, better quality and long-term data on the global environment and climate. The IPCC (Intergovernmental Panel on Climate Change) in its third assessment calls for “additional systematic and sustained observations, modelling and process studies”. The Montreal and Kyoto Protocol both contain chapters on the need for observations, analysis and research. The UN Convention on long-range trans-boundary air pollution (CLRTAP) requires a long-term consistent monitoring programme for air pollution. This information is needed for policy makers and to comply with the obligations of signatories.

Global measurement of the chemical composition of the atmosphere from space represents a relatively new technology, pioneered in the 1980’s by the NASA TOMS and SBUV sensors for stratospheric ozone. The technology was taken a step further in the 1990’s by the ESA GOME sensor showing that also the chemical composition of the troposphere was amenable to measurement from space. The technique was transferred to operational use rather rapidly. Ozone satellite data were assimilated into Numerical Weather Prediction models to improve forecast. The EUMETSAT MetOp satellite series (2005-2015, three satellites) were approved and carry the GOME-2 instrument. On the American side similar developments have lead to the NPOESS series (2008-2018, six satellites) carrying the ozone sensor OMPS. The Japanese NASDA satellite series GCOM (Greenhouse Gas Monitoring Satellite, 2007) is being redefined, carrying also instruments for tropospheric carbon dioxide and sulphur dioxide.

1.2 STUDY OBJECTIVES

In this proposal we address the following topics for operational atmospheric composition monitoring:

 Protocol Monitoring (Montreal and Kyoto Protocol emission reductions)  Air Quality Monitoring (CLRTAP, including EC directives on air quality)  Climate Monitoring (greenhouse gas and aerosol atmospheric composition trends)

 Policy Support (underlying information for policy makers and fulfilling reporting obligations)  Forecast (weather, surface UV level, ozone layer evolution, pollution health warning, aviation management)  Long-Term Science Issues (stratosphere, troposphere, climate-chemistry interaction)

These topics will be addressed from the perspective of a global monitoring system that integrates space and in-situ observations and responds to European end-user requirements. Since this involves a wide variety of requirements an important objective of this study will be to ascertain how well user requirements are met by the existing and approved mix of satellites and in-situ observation systems. Furthermore, it will be investigated how well user requirements could be met in the future through a better observation system, especially on the part of an operational atmospheric chemistry monitoring space mission. An important part of the study will be devoted to the identification of the appropriate user communities of which we present a first selection.

2 STUDY APPROACH AND STUDY LOGIC

2.1 STUDY APPROACH

The user side in this proposal is being represented by International, European and National environmental and climate agencies (WMO, JRC-IES, EEA-ETC/ACC, NILU, RIVM, ADEME, TNO), and meteorological forecast organisations (Meteo-France, Eumetnet, DMI, KNMI), and air traffic management organisations (Eurocontrol). The science side includes representatives from the major international and European (EC 6th framework) programmes (MPI-Mainz, ETH, U Heidelberg, CNR-ISAC, DLR).

The project will be led by the Royal Netherlands Meteorological Institute (KNMI) supported by a core group of Space Research organisations RAL, Univ-Leicester and Univ-Bremen, and Industry Astrium and Alcatel. These organisations will be supported in turn by a large consortium covering most interested parties in Europe, including LSCE Paris, Univ Oslo, USTL-LOA Lille, CNRS-LISA Paris, FZK-IMK Karlsruhe, CNRS-LMPA Paris, CNRS-SA Paris, CNRS-LPPM Paris, Noveltis Paris, CEA Paris, SRON Utrecht, BIRA-IASB Brussels, CNR-IFAC Florence.

A number of partners in this consortium have participated in previous assessment studies for ESA. In the ACECHEM, GeoTrope, and TROC studies the partners have established compliance of different mission concepts for different applications including existing and planned approved missions and ground networks. In the ESA study Pyramhyd atmospheric species with spectral signatures residing in the far infrared and sub millimetre part of the spectrum have been investigated by partners of this consortium. Information on other Earth Exoplorer proposals Olivia and Carbosat can be made available to the consortium. The work that has been performed for these assessments such as retrieval simulations, instrument requirement and mission concept studies, will be employed in the present study, albeit related to operational user requirements rather than scientific requirements. Expertise on present and planned European space missions is also available.

2.2 STUDY LOGIC

In Task 1 the user requirements for the applications referred to will be formulated on the basis of the outcome of a workshop held directly after kick-off and involving all users in this consortium. At mid-term review these users will be presented with the users requirements as formulated and iterated in Tasks 1 and 2. In Task 2 the user requirements are related to quantitative observational requirements, which are formulated in WP 2100. The existing and planned missions are assessed in WP 2200 for their contribution to these requirements, and the missing requirements are identified. In WP 2300 the results will be viewed from the more general perspective of higher- level information requirements formulated in Task 1, as compared with data level 2/3 requirements in Task 2. The result of Tasks 1 and 2 will be a consolidated set of user requirements that will serve as input to Task 3. In WP 3100 and WP 3200 instrument performance and requirements are derived. In WP 3300 and WP 3400 the respective space and ground segments of an operational mission will be formulated. These may be individual or a combination of missions. In Task 4 conclusions and recommendations of the study are formulated on the basis of consensus.

The mission concepts will be based on user requirements (spatial range/resolution, temporal resolution and range, data accuracy), technical aspects (measurement principle, spectral range/resolution/accuracy, spatial sampling, instrument concept requirements) as well as operational aspects (reliability, availability and accessibility of the data). The activities in WP 3000 will be limited to aspects which are required by the user communities and which are not

already covered by existing operational systems. New space segments will be defined only if it can be argued that these are needed in addition to the existing and planned approved operational monitoring missions and ground networks.

All currently known operational and planned atmospheric chemistry space missions will be reviewed as well as the international and European operational in-situ systems. Obviously, this being an European study it will be viewed from a European perspective on data availability. European space missions will include ERS-2 with GOME and ATSR-2 on board, ENVISAT with MIPAS, SCIAMACHY, GOMOS and AATSR instruments, ODIN with OSIRIS (UV-vis) and SMR (heterodyne radiometer) on board. In future, the EUMETSAT Polar System with the MetOp series will form the prime focus with the instruments GOME-2 and IASI on board. The geostationary EUMETSAT MSG (SEVERI) will provide additional information. Attention will be devoted to the priority listing of the ESA Explorer selections containing the highly ranked TROC mission and the GeoTROPE mission recommended for further study in the context of EUMETSAT Meteosat Third Generation MTG. The accompanying ground system will also be given attention. The EUMETSAT Satellite Application Facility (Ozone SAF) will stand model for an operational service for ozone and other trace gases, aerosols and ultraviolet data.

US space missions for atmospheric chemistry considered in this study will include UARS, EOS- Terra (MOPITT), and the future EOS-Aura with OMI, TES, HRDLS and MLS on board, as well as the future NPOESS mission with OMPS on board. Also the carbon dioxide instrument OCO (Orbiting Carbon Observatory) of the NASA ESSP-3 programme and the ozone instrument DSCOVR (Deep Space Climate Observatory, formerly Triana) to be positioned in the Lagrange point 1, will be considered assuming these missions are going to be approved. The observational capabilities of earlier occultation sensors SAGE-II (uv/vis), HALOE and ILAS-I (ir) are well- established and offer a reliable guide to this study. On the Japanese side the ADEOS-2 (2003, 2007) with TES and ILAS-II on board and GCOM (payload TBD) will be considered. The Canadian ACE mission will be considered as well as the Russian Meteor-3M both carrying ozone sensors.

3 USER COMMUNITIES AND APPLICATION REQUIREMENTS

3.1 ATMOSPHERIC COMPOSITION: THE MAIN ISSUES

Air quality has become a problem of global dimensions. The geographical scale at which degradation of air quality takes place expanded from city size in the 19th century to regional scales in the second half of the 20th century, and to continental and hemispheric scales in the last few decades. Examples of large-scale pollution include the “Asian brown cloud” observed during the INDOEX campaign (Ramanathan et al., 2002, Current Science, 83(8), 947-955), the wide-spread Kalimantan fires, most dramatically in the El Nino year 1997, and also the biomass burning fires threatening the Moscow area in August 2002. Nowadays clean air, in the sense of air unaffected by human influence, is not available anymore on the planet.

Photochemical air pollution has two components: toxic gases and fine particles (aerosols). Air quality regulations are in practice for surface ozone and its precursors, and for SO2. Air quality regulations for fine particles typically refer to PM2.5 and PM10, which refers to particulate matter with sizes up to 2.5 microns and 10 microns, respectively.

Projections for future atmospheric composition (IPCC, 2001) show increasing global-scale background levels of tropospheric ozone and its precursors (CO, NOx and (oxygenated) hydrocarbons, including CH4). This increase in background concentrations is a very important finding affecting present-day and future regulations, because enhanced background levels of pollutants will impede effective regional and national governmental policy actions to improve air quality on regional and national scales. How to cope with the international aspects of air quality control in the future is a challenge for the international community. There is an urgent need to install adequate monitoring systems for the changing atmospheric composition to be able to quantify the response of the atmosphere to present-day and future regulations.

Global climate-change is being observed with unambiguous human influence (IPCC, 2001) and it has profound societal impacts. Anthropogenic induced climate change is forced by increasing concentrations of greenhouse gases and by aerosols. The most important forcing gases are CO2, CH4, N2O, CFCs and tropospheric O3, driven by anthropogenic emissions of CO2, NOx, CO, N2O, CFCs, CH4 and non-methane hydrocarbons. Aerosols can be either emitted directly, e.g. in the form of soot, or form indirectly in the atmosphere from emitted gaseous precursors such as SOx, NOx and NHx.

Feedback mechanisms in the climate system may significantly counteract or re-enforce human- induced climate forcing, e.g., by changes in (surface) temperature, radiation balance, the hydrological cycle including water vapour, cloud formation, etc. Important interactions between climate and atmospheric composition take place in the upper troposphere and lower stratosphere (the ‘’UTLS region’’) where e.g. local ozone concentrations are tightly coupled with radiation, temperature and atmospheric dynamics. Long-term monitoring of the climate gases and aerosols is needed to quantify human-induced climate forcing by improved understanding of the controlling budgets, including (the distribution of) sources and sinks, the total burden, spatial variability and temporal variability up to decadal time scales.

Ozone layer recovery is generally assumed to occur in response to the policy measures taken following the Montreal protocol and its Amendments and Adjustments. There is a need for a long-term monitoring of the ozone layer to quantify the ozone recovery during the 21th century in response to the imposed ban of ozone depleting chemicals. For other policy regulations such as the Kyoto and UNCLRTAP protocols there is a similar need to support policy with operational

monitoring systems of atmospheric composition. The aim of such systems should be to quantify unambiguously the effect of policy measures on the atmosphere, or the absence of any effect.

Global change concerns the wider issue of human influence on the Earth system. Air quality, global climate change and ozone layer recovery are the major atmospheric aspects of global change. Global changes in the atmospheric composition are assumed to occur at rates that may be measurable on timescales of a decade or more. To monitor global change on such long timescales requires dedicated operational systems with a backbone in space and complemented by in-situ measurements.

3.2 SPACE MISSION OBJECTIVES

Considering the main issues playing a part in atmospheric composition, and considering the study objectives presented in chapter 1.2, the following subjects are grouped together in order to define four space missions objectives:

 Protocol Monitoring and Policy Support  Air Quality Monitoring and Policy Support  Long-term Science Issues and Climate Monitoring  Forecast Capacity

3.3 PROTOCOL MONITORING AND POLICY SUPPORT

Background

The Montreal Protocol (1987) to the 1985 Vienna UN Convention for the protection of the ozone layer is a classic example of an international agreement with a major impact on man-made emissions and the global environment. The UN Framework Convention on Climate Change (UNFCCC) adopted at the Earth Summit of Rio de Janeiro in 1992 and the resulting Kyoto Protocol (1997) commits the EU to cut its emissions of greenhouse gases by 8% in the period 2008-2012 compared with 1990 levels.

An important element in both conventions is the need for monitoring the emissions and monitoring the resulting change in composition of the atmosphere. Although an increasing number of observation stations on ground and in space are put in place there is still a need for more and better data. For example, ozone monitoring requires a long term and consistent data record. Yet, present surface and satellite based observation systems are not well integrated. For the Kyoto Protocol an independent observation system for the monitoring of greenhouse gas emissions on a global scale does not exist. This seriously limits the (independent) verification of Protocol targets.

The Sixth Environment Action Programme of the European Community (1), contains a number of relevant articles: Climate Change (Art. 4 and 2.3), Air Quality (Art. 6.5 and 2.5), Enlarged EU (Art. 2.8), Sound knowledge and Involvement of (policy) data users (Art. 9). The EU policy and measures to reduce greenhouse gas (GHG) emissions is defined in the European Climate Change Programme (ECCP). This programme and a number of Council and Commission decisions stress the need for monitoring GHG emissions and sinks as a means for assessment of progress toward meeting Kyoto Protocol targets (2). The GMES initiative is also of relevance here as it will cover atmospheric chemistry issues. It is represented in this study through the approved GATO project.

References: (1) EC 6EAP “Environment 2010: Our future, Our choice”, COM(2001)31final of 24.1.2001 (2) “Towards a European Climate Change Programme (ECCP)” COM(2000)88.

Montreal Protocol The discovery of the ozone hole and the scientific understanding of the processes that lead to the depletion of ozone have resulted in the signing in 1987 of the Montreal Protocol on Substances that Deplete the Ozone Layer. Subsequent amendments and adjustments of this protocol are based, and will be based on current scientific, environmental, technical, and economic information. To provide that input to the decision making process, advances in understanding on these topics were assessed in the 1989, 1991, 1994, 1998 and 2002 UNEP-WMO Scientific Assessment of Ozone Depletion. In turn, these assessments are based on observations of the abundance of ozone depleting compounds and the long-term monitoring of the ozone layer. Apart from measurements made from the ground, in particular from stations that are part of the WMO-GAW and NDSC network (e.g. Brewer, Dobson, DOAS, ozone sonde, lidar, microwave), and in-situ measurements during major field campaigns (e.g. the European EASOE, SESAME, THESEO, and VINTERSOL projects), satellites play an increasingly important role in these ozone assessments The series of TOMS instruments have been crucial in monitoring the changes in ozone from 1979 until the present. The European contribution to ozone monitoring with satellites has started in 1995 with the GOME - Global Ozone Monitoring Experiment on the ESA ERS-2 satellite. This ozone measurement series in the UV-visible spectral range will be continued with SCIAMACHY on Envisat, OMI on EOS-AURA and GOME-2 on the METOP series. Recently, the NASA mission QuickTOMS failed. As a result there will most probably be a measurement gap between the current Earth Probe TOMS and OMI. The European instruments GOME and SCIAMACHY play an important role to fill this gap and to ensure a continuous monitoring of the ozone layer on a global scale. From 1994 in-situ measurements on commercial airliners have been performed on a regular basis. The first initiative was MOZAIC with measurements of ozone and relative humidity. Later similar projects, such as CARIBIC and NOXAR joined. Currently these projects provide detailed in-situ observations of more than 60 tracer species, covering a large part of the globe, and provide the most valuable and extensive in situ data base to date. Europe is playing the leading role in this observational network and the value is being recognized outside Europe. Data assimilation combines models of the evolution of the atmosphere with observations of different atmospheric constituents and at different times and places. As a result the sequence of measurements provided by the satellite instrument, are converted into global, synoptic maps of ozone including the uncertainty. Such maps are validated against independent ground-based observations in a straightforward manner. Data assimilation is also instrumental for integration of data of different source, i.e. in-situ and satellite data. The monitoring of the evolution of the ozone layer, its possible recovery and the subsequent surface UV levels requires a long term and consistent data record. Emissions and subsequent concentrations of the ozone-depleting substances should be monitored. To monitor ‘’events’’ such as the annual polar ozone losses and ozone mini-holes near-real time information is needed. The main product for monitoring the evolution of the ozone layer is the (assimilated) ozone field, both in near-real time and in off-line climatologic mode. In order to ensure long-term continuity and consistency there is a need for better integration of space and surface based data. This need is recognised by WMO and CEOS in a recent initiative (WMO/CEOS report 140). The main customer is WMO. Other users may follow if usefulness is demonstrated. UV forecasters such as KNMI, Meteo-France and DMI are users of the near-real time ozone fields. Near-real time information is also input to the WMO ozone bulletins.

References: (1) WMO, Scientific Assessment of Ozone Depletion: 1998 (2) WMO, Global Ozone Research Monitoring Project Report 44 (1999) (3) UNEP-WMO Scientific Assessment of Ozone Depletion, Executive Summary, July 2002. (4) WMO/CEOS Strategy for Integrating Satellite and Ground-based Observations of Ozone WMO-GAW Report No 140 (2000).

Kyoto Protocol Global greenhouse gas emissions and absorptions, sources and sinks, are not well known. There is a large discrepancy between bottom-up emission estimates, derived from national government energy, transport, agricultural, etc figures, and top-down estimates derived from atmosphere concentration distributions. Better source and sink estimates are needed in support of the Kyoto Protocol monitoring, verification and reporting requirements. Global distributions of greenhouse gases need to be monitored in the troposphere where radiative forcing is strongest. The measurements of ENVISAT, particularly the instruments SCIAMACHY and MIPAS are expected to provide improved greenhouse and related gas distributions and emission inventories. Improvements will be achieved through a combination of measurement, retrieval, data assimilation and (inverse) modelling. It is expected that improved global emission estimates of methane, carbon monoxide and carbon dioxide will become feasible. Other relevant greenhouse and related gases will also be monitored.

The global scale of the protocol-monitoring requirement dictates the use of satellites as the only means of getting global coverage at reasonable spatial and temporal resolution and in a cost effective manner. The reliability and global sampling of satellite observations help to establish long term monitoring series (trends). The fact that the accuracy of the satellite data is often not good enough for treaty verification shows that space data alone cannot solve the problem this decade. Improved methods need to be based on integration of surface data and space data into models. In combination, the information is expected to become useful for end-users.

The user community targeted for the Kyoto Protocol are national and international environmental and climate change agencies. Users participating are EC JRC IES in relation to EC DG Environment and NILU in relation to the emission data base EMEP. IGBP-IGAC participates in the consortium via MPI Mainz.

References:

(1) Council Decision for a monitoring mechanism of Community CO2 and other greenhouse gas emissions (1999/296/EC). (2) Climate Change-Towards an EU Post-Kyoto strategy. Communication of. Commission to Council and European Parliament, COM(98)353. (3) Preparing for Implementation of the Kyoto Protocol, COM(1999)230.

3.4 AIR QUALITY MONITORING AND POLICY SUPPORT

The United Nations Economic Commission for Europe (UN/ECE) Convention on Long-Range Trans-boundary Air Pollution (CLRTAP) (http://www.unece.org/env/lrtap/lrtap_h1.htm) requires a long-term consistent monitoring programme for air pollution. The EU is signatory of this convention and has introduced European controls on emissions of sulphur, nitrous oxides (NOx), volatile organic compounds (VOCs), heavy metals, persistent organic pollutants (POPs). The most recent 1999 protocol further introduces a multi-pollutant approach to reduce emissions of sulphur, NOx, VOCs and ammonia, in order to reduce acidification of lakes and soils, eutrophication, and ground-level ozone. These gas phase pollutants are converted to sub-micron aerosols, which apart from their contribution to acidification and eutrophication have a cooling effect on climate and may cause human health problems (1-6).

The EU is also strongly committed towards cleaner air with the Clean Air for Europe (CAFE) programme (http://europa.eu.int/comm/environment/air/cafe.htm). The objective of CAFE is to develop, collect and validate scientific information relating to the effects of outdoor air pollution, emission inventories, air quality assessment, emission and air quality projections, cost- effectiveness studies and integrated assessment modelling. This information is leading to the development and updating of air quality and deposition objectives and indicators and identification of the measures required to reduce emissions (7).

The European Environmental Agency (EEA) is the European coordinating facility of the EC DG Environment and is organised along a number of Topic Centres. Relevant here is the European Topic Centre on Air and Climate Change. The ETC/ACC consists of a consortium of 13 European institutes lead by RIVM and NILU, both participating in this proposal. The ETC/ACC focuses activities on two main policy processes and frameworks:

 Climate Change (ECCP, EU monitoring mechanism and UNFCCC)  Air pollution (CAFÉ and CLRTAP)

The products and services from the ETC/ACC on climate include development and maintenance of Climate Change indicators, compiling the EU GHG inventory and assessing past and future inventory trends. The products and services from the ETC/ACC on air pollution include Report on Air Pollution in Europe including trends and appraisal of current policies, CLRTAP emission inventory, maintenance of the air quality information system AIRBASE and support to the CAFÉ programme. It will also develop information systems on air quality and emissions via Internet.

EMEP (European programme for Monitoring and Evaluation of long-range transmission of air Pollutants in Europe http://www.emep.int/) forms part of CLRTAP. The Convention contains eight Protocols aimed at the reduction of emissions of air pollutants; sulphur dioxide, nitrogen oxides, VOCs, heavy metals and POPs. EMEP runs a measurement network collecting air and precipitation measurements related to the emissions above, and develops models that estimate concentrations and depositions from emissions and input of meteorological data. EMEP has three centres that coordinate these activities of which NILU is one. There are two large databases; the measurement database and the emission database.

The EMEP implementation programme and the various EU directives on air quality (1-5) will be making contributions on various levels. The AIRBASE database of the ETC/ACC will form the project reference for the European ground-based observation network (6).

The user communities targeted are national and European environmental agencies. Users participating are the Norwegian NILU Topic Centre for Air and Climate Change of the European Environmental Agency (EEA), the Dutch environmental agency RIVM also with the Topic Centre for Air and Climate Change, the European Commission Joint Research Centre Institute for Environment and Sustainability (EC JRC-IES), the French environmental and energy management agency ADEME, and the Dutch TNO-FEL organisation on environment (aerosol).

References (1) Council Directive 96/62/EC on ambient air quality assessment and management.

(2) Council Directive 1999/30/EC on SO2, NOx and particulate matter. (3) Directive 2000/69/EC on CO and benzene.

(4) Directive 2001/81/EC on national emission ceilings for SO2, NOx, VOC and NH3 attained by 2010 (5) Proposal for a directive of the European Parliament and of the Council relating to ozone in ambient air and ceilings on atmospheric pollutants. OJ#C56E 29.2.2000. (6) Commission Decision 97/101/EC on reciprocal exchange of information and data from networks and individual stations measuring ambient air pollution within the Member States 2001/752/EC. (7) Clean Air For Europe (CAFE) programme, COM(2001)245 of 4.5.2001

3.5 LONG-TERM SCIENCE ISSUES AND CLIMATE MONITORING

The key science questions on the human impact on climate and on chemistry-climate interactions have recently been summarised in the ACECHEM report as follows:

 A1 Is the ozone layer recovering due to the phase-out of CFCs as predicted by the current models? What are the time scales of recovery?  A2 How does the atmosphere cleanse itself from the emissions of carbon monoxide, nitrogen oxides, methane, and other hydrocarbons, and how will the oxidising capacity of the atmosphere evolve in the future?  A3 What is the influence of pollutant export from industrial regions (northern America, Europe, Asia) on the distribution of species in the remote free troposphere on the global scale?  A4 What are the atmospheric effects of current and future aircraft?  A5 What is the effect of tropical biomass burning emissions on the composition of the troposphere and lower stratosphere? What is the importance of convection and lightning emissions on the photochemical production of ozone in the tropics?  B1 What are the abundances and spatial and temporal variabilities of the climate gases (including H2O)? What is their radiative forcing and what are the effects of atmospheric chemistry on this forcing?  B2 What are the abundances and spatial and temporal variabilities of aerosols, cirrus clouds, and PSCs, and what is their climatic and chemical effect?  B3 What is the distribution and variability of ozone in the upper troposphere and middle atmosphere? What are the chemical and dynamical causes and what is the climatic effect?

Space mission requirements for these questions have been established in the ACECHEM study.

Many of the above questions are subject to the IGAC (International Global Atmospheric Chemistry) project, members of which are represented in the CAPACITY team. IGAC is sponsored by IGBP and by IAMAS (International Association of Meteorology and Atmospheric Sciences.

SPARC is a research project established in 1992 by WCRP on the role of the stratosphere in in a changing climate and the feedback of climate change on the stratosphere. Participants of SPARC are represented in the CAPACITY team.

The European EUROTRAC project TROPOSAT aims at improving the use and usability of space data for exploration of the troposphere. It brings together data retrieval, calibration and validation experts and modellers from Europe. The role of the troposphere is of prime importance in climate and climate change. Participants of TROPOSAT are represented in the CAPACITY team.

3.6 FORECAST CAPACITY

Medium-range (up to 10 days) forecasts of ozone, based on the assimilation of near-real time ozone satellite measurements, have become available in recent years. The ozone forecasting system of the KNMI has been shown to produce meaningful ozone distributions for forecast periods of up to one week (Eskes et al., 2002). Such ozone predictions are important for UV forecasting and for the prediction of large and rapid ozone variation such as excursions and break- up of the ozone hole, and the occurrence and evolution of "mini-ozone hole" events. For instance, the spectacular break-up of the 2002 ozone hole in the period 23-28 September was predicted

successfully more than a week in advance by the KNMI ozone forecasting system. Operational forecast experience at KNMI exists within the ESA DUP projects GOFAP (GOME Fast delivery and value Added Products) and TEMIS (Tropospheric Emission Monitoring Internet Service) and the nationally funded SCIAMACHY Data Centre.

Weather centres, in particular the ECMWF and Météo France, have recently started activities on the assimilation of satellite ozone data. The main motivation is an anticipated improvement of the description of radiation, wind field and infrared satellite retrieval resulting from the detailed 3D ozone field in the NWP model. The resulting analysed ozone fields are an important spin-off in the context of Montreal protocol monitoring: the reanalysis data sets (ECMWF 40-year reanalysis currently produced) will be a valuable source of information on the development of the ozone layer over the past decades. Numerical modelling of atmospheric chemistry by Météo-France is based on the three- dimensional model MOCAGE [Peuch et al., 1999]. MOCAGE covers both the troposphere and stratosphere and offers a possibility to zoom in from the global scale to the regional scale. It is interfaced with Météo-France operational numerical weather prediction models (ARPEGE, ALADIN) as well as with the European Centre for Medium-range Weather Forecast model (IFS). This combination of models can be seen as a prototype for “chemical weather forecast” delivering daily forecast runs of up to 96 hrs. Products include surface air quality predictions and UV index forecasts (http://www.meteo.fr).

The depletion of the ozone layer leads on the average to an increase in the ground level UV-B radiation. The level of UV radiation depends on a number of atmospheric constituents (gases especially ozone, aerosols and clouds) and albedo. In order to monitor and forecast UV-B, precise measurements of these quantities must be made. It is of importance to be able to distinguish urban and rural areas, therefore good spatial and temporal resolution is required. Presently, the main uncertainty in the calculated UV-B results from uncertainty in atmospheric constituent concentration distribution

EUROCONTROL is the European Organisation for the Safety of Air Navigation. This civil and military organisation is responsible for air traffic management matters over Europe. Its primary objective is to develop a European air traffic management system that fully copes with the constant growth of air traffic, while maintaining a high level of safety, reducing cost and paying due respect to the environment.. ESA and EUROCONTROL have concluded a cooperation agreement that contains a technical annex on environmental matters. In relation to this agreement EUROCONTROL has expressed interest in the outcome of the CAPACITY study. One concrete example concerns the prediction of volcanic plume occurrence. Advance knowledge on how to reroute air traffic to avoid volcanic plumes would yield a high safety and economic benefit. Other applications that will benefit from atmospheric chemistry forecasting include natural hazards and disaster monitoring, biomass burning catastrophes, lightning and other subjects to be defined during the study.

The forecast capacity will be mainly the domain of the meteorological community. Partners are Meteo-France, KNMI, NILU(NADIR database) and DMI representing Eumetnet. Eurocontrol will act in the study as end-user of chemical weather forecasts based on satellite products.

3.7 USER REQUIREMENTS

The extent to which these existing and planned space missions can potentially fulfil requirements of the monitoring applications to be defined in this study will depend upon the suite of

constituents selected for each application, the height range in which they have to be monitored and the horizontal and temporal resolution and accuracy requirements which are placed upon them. Although User Requirements cannot be predicted in advance, we have two pre-conceptions in regard to existing and planned missions.

Firstly, User Requirements are likely to focus strongly on the troposphere and lower stratosphere. These regions, especially the troposphere, are very challenging to sound from space, so requirements can be anticipated to be demanding, and therefore unlikely to be met in full by existing and planned missions. Although capabilities to monitor certain key constituents of the stratosphere accurately over extended periods, albeit with fundamental sampling limitations, have been established by SAGE-II and HALOE, such capabilities have yet to be established for any constituents of the troposphere.

Secondly, User Requirements are likely to extend beyond the lifetimes of existing and planned missions. It is nonetheless envisaged that the MetOp and NPOESS missions, scheduled to commence in 2006 and around 2008, respectively, are likely to make significant contributions to future monitoring of tropospheric constituents, by virtue of the advanced designs of their instrumentation and their longevity.

A key issue for the proposed study will therefore be to evaluate the MetOp and NPOESS contributions and to gauge how best to consolidate and complement these. MetOp and NPOESS have in common their global observation mode from polar, sun-synchronised low Earth orbit (LEO). Global coverage is realised after one to six days depending on instrument and application. This orbit constraint precludes the capture of the diurnal variation of atmospheric species, which requires (sub-)-hourly temporal resolution. Since key tropospheric constituent such as ozone, NO2, SO2, CO, water vapour, cloud and aerosol display strong diurnal variability, the LEO measurement alone cannot provide a comprehensive answer to the main issues identified, in particular the issues concerning Air Quality Monitoring and Forecasting. This objective can however be fulfilled by observation from geo-stationary orbit (GEO). Therefore a comprehensive system is expected to consist of a combination of complementary satellites in GEO and LEO orbits. In this case data merging issues form an important part of the integrated system definition.

3.7.1 Protocol Monitoring and Policy Support

Atmospheric gases to be considered in this mission objective are defined in the Protocols. For the Montreal Protocol this concerns emissions of a large variety of CFC's, HCFC's and PFC's. Of prime importance is the monitoring of the stratospheric ozone layer and establish the effect of Protocol measures. The longevity of CFC's causes temporal and spatial variation of the atmospheric distributions to be minimal and hence extreme measurement accuracy would be required to establish sources and sinks. Currently the trend in concentration is monitored from surface stations. To measure the trend in stratospheric ozone concentration measurement accuracy must be around 1% or better as decadal changes of the order of a few percent must be captured.

A number of gases play a crucial role in stratospheric ozone chemistry including the catalytic cycles of hydrogen, nitrogen and chlorine. A key role in the heterogeneous ozone chemistry is being played by the presence of PSC. Key constituents need to be measured in order to understand the underlying processes that lead to ozone destruction.

The Kyoto gases included in the Protocol are CO2, CH4, N2O, SF6, HFC and PFC. The Kyoto Protocol requires emissions to be reduced by approximately 10% at the end of this decade compared with 1990 levels. Establishing emissions is an important but challenging task, in part again because of the longevity of these species (timescales of 100 years) and therefore their small temporal and spatial variability, the exception perhaps being methane.

Greenhouse gases not included in the Protocol are water vapour being the most important greenhouse gas and tropospheric ozone, expected to become as important as methane in its contribution to radiative forcing. A further important atmospheric constituent not mentioned in the Protocol is aerosol, important for having in some cases a substantial cooling effect (SO2) and in other cases a warming effect (soot). Also the indirect greenhouse effect via cloud nucleation is of relevance here as are clouds by themselves. In contrast to the Kyoto gases the non-Kyoto greenhouse constituents are characterised by their high variability in space and time.

A number of chemicals play a key role in tropospheric chemistry and must also be included. This refers to NO2 intimately coupled to the production of tropospheric ozone and CO as a precursor to anthropogenic carbon dioxide emissions.

As a first iteration, the requirements for Montreal protocol monitoring are found in the WMO- CEOS report 140. The WMO-IGACO project will provide new insight and approaches to integration of space and in-situ atmospheric chemistry data. New insights on Kyoto Protocol monitoring are presented in the GeoTROPE and TROC studies. Tables A1 and B1 of the ACECHEM Final Report will provide reference information.

3.7.2 Air Quality Monitoring and Policy Support

For the CLRTAP protocol the processes to be monitored are taking place in the troposphere. One of the recent advances in earth observation has been the ability to probe the troposphere from space. For example, the nadir looking instruments GOME and ATSR on the ERS-2 satellite have demonstrated that total column and tropospheric columns of O3, NO2, SO2, H2O, BrO, and HCHO, O3 profiles, UV-A, UV-B, cloud and aerosol parameters can be successfully retrieved from the UV-VIS-NIR measurements. Measurements from ENVISAT and from MetOp are expected to improve the present capability to probe the troposphere.

The limitation of these observations lies in the satellite orbit, which is polar and sun- synchronised. Synchronisation with the sun excludes the measurement of the strong diurnal variability displayed by air pollutants and therefore, such measurements are not representative for the concentration distribution and their inventory trend. It will also be difficult to extrapolate forecasts from one time of the day measurement.

In situ measurements are point measurements spread over a number of sites. For EMEP these can be rather large for some species, e.g. the number of sites performing nitrogen dioxide can be close to a hundred. For others, the number of measurement sites (VOC) is less than ten.

Satellite based information may be used to improve the spatial extent and resolution of emissions. Inverse modelling (based on accurate concentration measurements) can be applied to reduce the uncertainties in current emission inventories of ground level air pollution. For evaluating effects of AP on human health and ecosystem detailed spatial information is needed. Satellite data could be used to improve the coverage of the ground based monitoring network. The temporal resolution of present satellites is of concern; most air pollutants show strong diurnal and seasonal variation. Corrections have to be defined as a polar satellite passes at a fixed time of day. Also, troposphere measurements can only be made under cloud-free conditions. This implies that present satellite measurements are not representative for longer-term (e.g. annual) average values. The ETC/ACC focus is on ozone, PM10, PM2.5 and their precursors. The EMEP models calculate averages over a grid with a 50 km x 50 km resolution. The required accuracy for many components, e.g. sulphur dioxide in air, is 10 to 25 per cent. Typical components of interest may be nitrogen oxides and particle concentrations (~PM10). The concentrations should be at or near the surface since the long-range transport of air pollution taking place within the boundary level.

The current EU directives on PM10 (particulate matter below 10 mm in size) will be reviewed in 2003 and likely PM2.5 (particulate matter below 2.5 mm) will be the new limit value, whereas epidemiologists are already considering PM1 (particulate matter below 1 mm). PM2.5 and PM1 are the aerosol fractions that contribute most to the radiation detected by satellites and preliminary results indicate the possibility to derive PM2.5 concentrations by using satellite data assimilation in chemistry transport models. Satellites allow extrapolating the spatial distribution of aerosol properties with a high spatial resolution (down to 1x1 km2 from ATSR-2 on ERS-2).

The EC directives (reference 1-5 in Chapter 3.4) form the basis for requirements on Air Quality. The approved EC GMES projects on aerosol GMES-DAEDALUS and atmospheric composition GMES-GATO will provide user specific requirements. The ESA Earth Explorer proposals for GeoTROPE and TROC form a reference for user requirements. The Tables A2 and A3 of the ACECHEM study will provide an additional source of information.

3.7.3. Long-term Science Issues and Climate Monitoring

The long term science issues and climate monitoring are extensively covered by the ACECHEM study and the subsequent proposal to ESA for an Earth Explorer Core mission. This mission is focussed on the Upper Troposphere, Lower Stratosphere (UTLS) region of the atmosphere, which is most sensitive to radiative forcing by greenhouse gases. Adequate height resolution and accuracy are the driving requirements.

As a first iteration, the requirements for this mission objective are summarised in the Tables A5 and B2 and B3 of the ACECHEM Final Report. The Eurotrac project TROPOSAT and the WCRP project SPARC and the IGBP project IGAC will provide input through consortium partners.

3.7.4 Forecast Capacity

Requirements for forecasting include timely (near-real time) delivery of global data to the processing unit. These data should also have high temporal resolution. Air quality forecast and health warnings would require at least an one hourly update of input data Forecast capacity depends on data assimilation into atmospheric chemistry dynamic models such as MOCAGE and TM3/TM5 employed by Meteo-France and KNMI respectively. Analysed wind fields from ECMWF feed these models. Since the availability of these data is almost solely confined to the meteorological organisations, with access to the ECMWF analysed wind fields, this part of the work is in the realm of meteorological organisation.

The Meteorological organisations KNMI, DMI(Eumetnet), Meteo-France and Eurocontrol will define requirements. In addition to the above requirements, environmental aspects of air traffic management are covered in the Table A4 of the ACECHEM Final Report, which will serve as a first iteration input to the study.

4 OBSERVATIONAL REQUIREMENTS PER TARGET APPLICATION

4.1 DERIVATION OF LEVEL 2/3 DATA REQUIREMENTS

In WP2100 the user requirements will be translated into quantitative level 2/3 product requirements. Quantitative requirements will be set for each of the defined applications. The data requirements will include atmospheric constituents, horizontal and vertical spatial resolution, temporal resolution, accuracy and coverage. For each application clear priorities will be given for mandatory and desirable parameters, respectively. Table 4.1 contains an initial list of geophysical parameters which are likely of most relevance to user applications. The list has been compiled from the ESA ACE-requirements study in combination with the ACECHEM proposal, and from a list of required and measurable products ‘for operational and climate applications’ as has been recently established for future measurements from geostationary orbit. The list is here included as a first iteration and it not necessarily complete. The initial list will be updated in iterations with the user communities during the study WP1000.

O3 ClONO2 CO SO2 PSC OD H2O CFC-11 CH4 AOD fine Cloud OD NO2 CFC-12 CH2O AOD coarse Cloud cover PAN HCFC-22 CO2 Aerosol SSA Lightning counts HNO3 HCl CH3COCH3 Aerosol Reff Surface UV N2O5 ClO C2H6 Cirrus OD Fire counts N2O BrO C2H2 Contrails OD Temperature Table 4.1. Initial list of geophysical parameters of possible relevance to operational atmospheric chemistry monitoring

The European EUROTRAC project TROPOSAT aimed at improving the use and usability of space data for exploration of the troposphere. It brings together data retrieval, calibration and validation experts and modellers from Europe. Within Troposat the confidence level for the measurement of some key trace gases in the troposphere has been evaluated, together with the principal (scientific) applications. These confidence levels, for the data products considered, will form an additional basis for the derivation of level 2/3 data requirements for operational applications.

Species Domain Confidence level Applications O3 T+S Total column: high Air Quality, Climate Change, Long-range Stratospheric profile: medium Transport, Weather Prediction Tropospheric column: low NO2 T Stratospheric column: high Air Quality, Long-range Transport, Emission Tropospheric column: medium Strengths CH2O T Total column: medium/low Air Quality, Long-range Transport, Emission Strengths SO2 T+S Total column: medium/low Air Quality, Long-range Transport, Emission Strengths H2O T+S Total column: high Weather Prediction, Climate Change Stratospheric profile: medium/low CO T Total column: medium/low Air Quality, Long-range Transport, Emission Strengths CO2 T+S Total column: Yet unknown Climate Change, Emission Strengths Stratospheric profile: low CH4 T+S Total column: Yet unknown Climate Change, Emission Strengths Stratospheric profile: low N2O T+S Total column: Yet unknown Climate Change, Emission Strengths Stratospheric profile: low

Table 4.2. The confidence level for the measurement of some key trace gases as been evaluated, together with the principal (scientific) applications, based on the Troposat final report and results that are available in the scientific literature.

The derivation of aerosol data requirements will be performed in interaction with the DAEDALUS project (2002-2005) as much as possible within the time frame of this study. The goals of the DAEDALUS project are highly coupled to the work that is proposed in the present study: - to advise on the optimum use of aerosol in-situ, ground-based and satellite remote sensing data to meet the users needs, - to deliver data and information to the users, - to make proposals for aerosol monitoring as part of the European capacity to be established for GMES and, - to develop the methodologies necessary for delivering operational aerosol products.

Data requirements for aerosols have also been compiled in the ACECHEM study mostly for the study of the climate impacts of aerosols. These aerosol parameters have beeen included in Table 4.1. Further aerosol data requirements for aerosol presence and aerosol extinction have been reported in the WMO/CEOS report on ozone (WMO/GAW report No 140, January 2001). These rather loose requirements (in terms of horizontal and temporal resolution) were intended for the study of heterogeneous chemistry, climate impact, and atmospheric corrections needed for chemical species retrieval from space.

It is now realised that global transport models -- some of which will be run in operational mode -- will provide useful information for a variety of applications such as monitoring of air quality, atmospheric correction of oceanic and land surfaces, impact on the ecosystems. The data requirements for assimilating gases and aerosols in such global models (which outputs can serve as inputs for smaller scale models) need to be reevaluated, both in terms of spatial and temporal resolution, timeliness, and accuracy.

4.2 ASSESSMENT OF CAPABILITIES OF EXISTING & PLANNED SPACE MISSIONS AND GROUND NETWORKS

The proposing consortium includes scientific institutes with specialist expertise in an extensive range of atmospheric measurement techniques, and particularly the retrieval of trace gas and aerosol distributions from remote-sensing measurements. Once the quantitative observational requirements have been defined for each application, an assessment will be made of the capabilities of existing and planned space missions and ground networks to meet these requirements. With respect to ground networks, remote-sensing and in- situ sensors will both be assessed. With respect to space missions, the starting-point will be findings from the ESA study on "Definition of Mission Objectives and Observational Requirements for an Atmospheric Chemistry Explorer Mission" (ESA Con 13048/98/NL/GD). In that study, having defined a set of mission objectives and observational requirements, the capabilities of individual sensors to observe individual trace gases were assessed on a common basis. The information from those individual assessments was then synthesized to gauge the capabilities at mission level, and for combinations of missions, to meet the overall requirements for each specific mission objective. From experience in the Explorer study, it will be important for requirements for each application to be considered in combination, both in terms of the geophysical quantities to be observed and the precision/accuracy/vertical resolution/geographical sampling/temporal sampling of each quantity.

The first step in the proposed study will be to update the assessments of individual sensor capabilities on the basis of: 1. The data quality achieved in practice by sensors now in operation, which had not been launched at the time of the Explorer study. 2. State-of-the art retrieval simulations performed since the Explorer study for sensors in planned missions, which have still to be launched.

In regard to (1), a wealth of new information will be available to the consortium on the timescale of the proposed study from, for example, the Odin, Envisat, Terra and Aqua satellites, and possibly also Aura. In regard to (2), since the original Explorer study, retrieval simulations have been undertaken by members of the proposing consortium in preparation for several planned missions. These will permit updated and improved estimates of observational characteristics and error budgets to be made available on, for example, MAESTRO/ACE, IASI and GOME-2 on MetOp, OMI, TES and HiRDLS on Aura, and SMILES on ISS

Within WP2200 it is proposed to exploit existing information as fully as possible, but not to process data from currently operating instruments, nor to undertake retrieval simulations (Both activities would be outside the scope of what is feasible within the resource envelope).

In the Explorer study, ground-based networks were not considered at all and the assessments of aerosol observations did not include quantitative information from real or simulated retrievals, so these elements of WP2200 will have different starting-points.

There are a number of well-established networks for ground measurements of atmospheric trace gases, notably including the Network for Detection of Stratospheric Change (NDSC), which consists exclusively of remote-sensing instruments. For ozone in particular, a variety of ground- based remote-sensors (e.g. Dobson, SAOZ, FTIR, mm-wave, Lidar) are routinely operated to measure total columns and/or profiles, principally stratosphere, and the ozone-sonde network provides profiles with high vertical resolution, which also extend down through the troposphere. Ozone data is archived by the World Ozone and UV Data Centre. Networks also exist for measurement of tropospheric trace gases specifically, in urban and rural locations, to monitor air quality and the background levels of pollutants involved in climate forcing and other global environmental problems. Historically, measurements of concentrations near ground-level have been made by in-situ instruments, however remote-sensors are now contributing increasingly.

Looking ahead, the existing ground networks will evolve in response to international initiatives (e.g. GMES-GATO). In addition to assessing their current capabilities in WP2200, plans for future development of the networks will be considered.

In recent years there has been a very strong development of a surface network for the monitoring of aerosol optical properties. This was initially based on a joint effort of USA and France, and was then extended to many countries. See the AERONET web site at http://aeronet.gsfc.nasa.gov. The sun-photometer network provides some information on the total aerosol column. An increasing number of applications require some information on the vertical distribution, which can only be achieved by the use of Lidar techniques. There are a few sites, which make routine measurements of aerosol properties with a lidar, although this network has not yet reached the same level of operationality as AERONET. The GLAS lidar was launched in January 2003. Although its main objective is the altimetry of ice caps, it also has atmospheric sensing capabilities. Available information from all the above sources will be critically reviewed in comparison to the defined observational requirements on aerosol.

Having established quantitatively the performances of individual sensors to meet requirements for individual trace gases and aerosol, this information will be synthesised to gauge the capabilities of missions and networks combinations of these, per application. In an analogous way to the Explorer study, findings will then be drawn in regard to each application, with a view to

identifying key observational requirements, which will remain unmet and therefore justify consideration for a future space mission WP3000. As a final step in WP2200, findings will be reviewed with the user group at Mid-Term Review

4.3 INTEGRATED OBSERVING SYSTEMS PER TARGET APPLICATION

Earthwatch recognises that data collection must be user driven, leading to information products that may increase scientific understanding but also guide early warning, policy setting and decision making for sustainable development and environmental protection. Within this work it is recognised that the monitoring of any user application may require a multi-mode observational strategy and this workpackage investigates the requirements for such a system.

In this workpackage, the objective is to identify the requirements for integrated observing system focussed on Earthwatch target applications. Earthwatch observing systems could comprise new satellite systems coupled to other added-value ground, airborne and spaceborne components. For example, in the measurement of ozone long-term trends, the Dobson ground-based network has been invaluable in establishing trends and in validating satellite datasets. It is also apparent that improvements in our modelling of atmospheric composition now permit the incorporation of data assimilation into system design and implementation.

This workpackage builds on the outputs from WP2100 and WP2200 to identify overall concepts of integrated observing systems and to ascertain the additional information gain from such systems. A further element arises from observables, which indirectly improve observations of the target variables and these will be considered as appropriate.

The specific aims of this workpackage are:

 To provide a vision of integrated observing systems per target application,  To identify ground-based, airborne and space-based components to the system that would add value (information) to observables directly required/measured by existing/potential new systems,  To consider the most pressing application questions and make recommendations as to potential elements of appropriate observing systems

Input to this workpackage are the user requirements from WP1000 and the results of WP2100 and WP2200. In order to fulfil the stated aims an iterative process will be undertaken. The logical sequence that will be followed is that an examination of the user requirements as formulated from the user consultation (WP1000) in the four application areas will be converted into a set of geophysical parameters (WP2100). In the light of these geophysical requirements per user application WP2200 will compare these to available or planned missions. The main work that will be undertaken in this area will be to identify the most pressing application areas, which require Earthwatch systems in light of existing/planned capabilities. Coupled closely to this will be assessments of the potential contributions of added value (information) from such elements as additional relevant capabilities of existing/planned satellite systems, elements of ground-based and airborne systems, observing strategies involving model analysis/assimilation systems. The end of this iterative process will lead to an assessment of requirements and potential for integrated observing systems (surface, airborne and satellite systems) which will include a match between key user drivers for mission concepts and possible outputs from integrated observing systems and

an assessment of the additional information gained from deployment of integrated system components (“missing” requirements).

An example of the work logic can be demonstrated by considering a user application centred around volcano eruption monitoring for air traffic management. This user application would have been identified by WP1000. The geophysical parameter that might best be measured would be

SO2 concentration in the troposphere (WP 2100) and this may be measured from current or planned missions as identified in WP2200. The work here would draw together, the user requirement, the availability of relevant measurements and couple them to the additional functionality offered from other measurements, for example, aerosol radiometers, SAR and/or GPS measurements on space-based platforms or ground-based sonde launches/airport observations. The additional measurements in effect complement the primary geophysical driver for this observation to provide a more integrated view of the hazard. It might also become apparent that there is a need for higher-level user products, which cannot be provided by an individual product. In this example there maybe a requirement for a product that can then be rapidly distributed to the airlines/ air traffic controllers to warn of the position, height and likely visibility in the volcano plumes. Such an information product could only be provided by an integrated observational approach. The net effect would be to deliver enhanced benefits to an integrated system targeting key geophysical parameters.

5 DERIVATION OF INDIVIDUAL AND COMBINED MISSION CONCEPTS

Mission concepts and instrument requirements will be derived per application. The possible synergies between different mission concepts for different applications will be sought. Synergistic elements and disadvantages will be worked out equally for combinations of missions.

5.1 INSTRUMENT PERFORMANCE AND REQUIREMENTS- GEO

Polar-orbiting satellites can provide high-quality measurements of atmospheric parameters, but are limited in temporal/spatial resolution and coverage by a combination of relatively low spatial resolution, non-contiguous data images (normally single swath), large variability in local cloud cover and daily revisit time. This currently puts limits on applications such as local/regional pollution monitoring and forecast as well as emission monitoring. In the troposphere the variability of chemical loss and source strength combined with the dynamics of transport and mixing induce significant short term, i.e. sub-hourly, variations and significant horizontal and vertical variability of constituents and geophysical parameters. The observational limitations of low-Earth orbit (LEO) platforms dictate that the troposphere therefore significantly under sampled. Consequently, there are application areas which require (sub-)hourly measurements, at appropriate horizontal and vertical resolution. Measurements from Geostationary Orbit (GEO) offer a practical approach to the observation of diurnal variation from space with the pertinent horizontal resolution. The use of a geostationary platform for atmospheric composition studies will offer (1) synoptic observations of geophysical parameters with significant diurnal or transient variations, (2) increased sampling of the troposphere because of the highly variable cloud cover, and (3) an insight into the interaction of smaller scale processes incl. pollution problems. Relevant trace chemical constituents are typically present in significant amounts in both the stratosphere and the troposphere (e.g. O3). Sounding the troposphere from GEO therefore necessitates looking through and accounting for the stratosphere and upper atmosphere. The separation of stratospheric and tropospheric amounts can be achieved by residual techniques already applied to data from LEO nadir instruments and by coupling the proven understanding of radiative transfer of electromagnetic radiation through the atmosphere with the multispectral advantage (i.e. measuring different characteristic spectral features from different spectral regions with different penetration depth into the atmosphere) and the spectroscopic knowledge of the temperature and pressure dependencies of molecular absorptions and/or emissions. Solar (UV, visible, NIR, and SWIR) radiation penetrates deep into the troposphere and down to the Earth's surface or cloud top. The application of various algorithms to data from TOMS, GOME and SCIAMACHY have demonstrated that total column and tropospheric columns of O3, NO2, SO2, H2O, BrO, and HCHO, CO, CH4, CO2, O3 profiles, UV-A, UV-B, cloud and aerosol parameters can be successfully retrieved from the UV-VIS-NIR-SWIR measurements. Nadir viewing of the emission of thermal infrared radiation (TIR) has also significant heritage in sounding tropospheric parameters like temperature, H2O, O3, CH4, N2O, and CO. Trace constituent information can be retrieved in the TIR from the middle troposphere and stratosphere as shown by sensitivity studies and demonstrated for example from the analyses of IMG aboard ADEOS. Similar retrieval schemes will be applied to the observations of TES (NASA-AURA) and IASI (METOP).

To achieve an optimal vertical resolution in the troposphere with a nadir sounding system, it is required to combine measurements of the backscattered radiation in the UV-VIS-SWIR with measurements of thermal emission in the IR. Potential mission concepts should therefore take into account UV-VIS-NIR-SWIR and TIR instrumentation in combination.

In WP 3100 applications with demanding requirements on temporal resolution/sampling and spatial resolution and coverage will be identified, level 2 requirements from task 2.3 will be transferred to quantitative level 1 and instrument requirements. This will be done based on results of already performed studies (ACECHEM, EOGEO/GEOEO etc.) undertaken by both scientific and industrial partners in the proposing consortium. These will be compared to the performance expectations from future geostationary instruments, deduced by retrieval simulations, which employ the up to date and realistic instrument specifications and error estimates. The European concepts GeoSCIA (UV-Vis_NIR-SWIR) and GeoFIS (TIR) as well as the US mission GIFTS (TIR) and the US concept GeoTRACE (UV-Vis_NIR-SWIR) will be taken into account in this study. The individual sensor capabilities will be evaluated quantitatively against requirements.

In a first step the contribution of single instrument concepts to the application areas will be evaluated. In a second step the combination of application areas as well as the combination of geostationary instrumentation will be investigated. Potential for upscoping or downscoping of individual sensors in order to better match requirements will then be examined. In a third step the benefits of the combination of LEO (from WP 3200) and GEO instruments will be briefly evaluated to give recommendations on the space component of an integrated atmospheric observing system. Technical feasibility and maturity of instrument and mission concepts will be reviewed within WP 3300. Ground segment concepts will be developed in WP 3400. Finally, the findings from this exercise will be reviewed with the user requirements.

5.2 INSTRUMENT PERFORMANCE AND REQUIREMENTS- LEO

The outcome of WP2000 will be to identify applications whose observational requirements are not fully or largely met by ground networks and planned space missions. The assessment of Low- Earth Orbiting (LEO) Mission Capabilities will commence by identifying, reviewing and updating information on concepts for a potential future LEO mission. As in WP2200, the starting point for this exercise will be the findings from the ESA study on "Definition of Mission Objectives and Observational Requirements for an Atmospheric Chemistry Explorer Mission" (ESA Con 13048/98/NL/GD). Subsequent to that scientific study, two pre-Phase A studies were performed by industry in preparation for the "Report for Assessment of the ACECHEM Candidate Earth Explorer Core Mission (ESA SP-1257(4)). A number of further studies of direct relevance to the assessment of a future LEO mission, dedicated to monitoring atmospheric composition have also been undertaken since the original Explorer study, by both scientific and industrial partners in the proposing consortium.

On the scientific side, these include: - The 1st and 2nd extensions to the original Explorer study, in which the specifications of candidate instruments have been iterated and refined on the basis of retrieval simulations - an ESA study on 2-D tomographic sounding of the UTLS, in which schemes for 2-D retrievals by limb-emission sounders (MASTER and AMIPAS) are being developed to capture horizontal and vertical structure with high fidelity.

On the technical side, these include studies by industry for ESA of the AMIPAS/LCI instruments and studies in the Netherlands and France of, respectively, an advanced uv/vis/nir grating spectrometer and an advanced FTIR spectrometer for nadir-sounding. Importantly, they will also include lidar concepts, which were not part of the original Explorer study. A further dimension to the review and update of LEO concepts will be to include, if available, early information on the performance of MARSCHALS; the airborne pre-cursor to MASTER, which may have its first flight opportunity early enough to feed in to this study. Information from the TELIS programme (a pan-European initiative to develop a balloon-borne limb-sounder with highly-sensitive sub-mm and THz receivers) will also be taken into account.

As in WP2200, individual sensor capabilities will in all cases be evaluated quantitatively against requirements, through retrieval simulations, which employ the most up-to-date and realistic instrument specifications and error estimates. Our pre-conception is that user requirements defined in WP2100 will point towards a polar sun-synchronous orbit rather than a precessing low- earth orbit because, for monitoring, it will be vital to sample every day at the same local time of day. (A precessing LEO mission would mix inextricably local time variations with longer-term variations.)

Again, as in WP2200, having established quantitatively the performances of individual sensors to meet requirements for individual trace gases and aerosol, this information will be synthesised to gauge the capabilities of the identified LEO mission concepts, per application. In an analogous way to the Explorer study, findings will then be drawn in regard to each application.

Potential for upscoping or downscoping of individual sensors in order to better match requirements will then be examined and an assessment will be made of two specific mission combinations:

1. MetOp plus dedicated limb mission 2. Dedicated nadir plus limb mission

Finally, the findings from this exercise will be reviewed with the user requirements.

5.3 DERIVATION OF MISSION CONCEPTS – SPACE SEGMENT

In this workpackage ASTRIUM will support the definition of mission requirements and propose mission concepts. The mission definitions will contain:

 Definition identifying the space segment  Type of mission: single satellite, constellation or formation  Type of orbit: LEO, MEO or GEO  Specific requirements to orbit: (e.g. sun synchronous, coverage constraints, revisit times)

 Definition of the instrumentation. For each instrument:  Type measurement principle  Measurement requirements (in requirement parameters as typical for level 1b data products  Coordination (if applicable) with other instruments on the same platform or formation (e.g. alignment of IFOV)

For each of the defined mission requirements a mission concept will be proposed. The concept will cover orbit selection, assessment of the key parameters of the space segment (approximate size, pointing requirements, general characteristics of power S/S and AOCS, concept of mission operation and data downlink). The instrument requirements as elaborated in (WP3100 & WP3200) will be reviewed and analysed with respect to implementation options and technological constraints. Analysis will be based on extrapolation from existing or planned missions and instruments. ASTRIUM will use its experience in planning and implementation of earth observation missions and instrumentation for these missions to assess technical criticality of the proposed missions and their instrumentation. Considering the technological state of the art critical technologies and development needs will be identified. Main cost drivers of the proposed missions will be identified.

When analysing missions the possibility to combine missions originally targeting to different user needs will be considered. If appropriate modifications to initially envisaged missions or mission parameters such as instrument complement or preferred orbit characteristics will be suggested. If analysis of technical complexity leads to the conclusion that some technical instrument parameters or operational aspects are cost drivers and a relaxation of requirements would likely lead to significant cost reduction an appropriate simplified mission option will be proposed for trade-off with the original concept.

5.4 DERIVATION OF MISSION CONCEPTS – GROUND SEGMENT

The Ground Segment provides the service segment timely access to quantitative image products acquired by the space segment. This includes all functions from user order desk, through satellite tasking, data acquisition, and product generation. The ground segment is also responsible for monitoring the health of the satellites and instruments. The design of the ground segment must focus on the requirements of the applications. In order for the mission to be a success, basic and intermediate data products must be made available in a timely fashion, and delivered in a manner which integrates into the service sector’s value added processing chain. The Ground Segment supports the application services by providing a set of tools and interfaces to task the satellite, and to process the raw imagery to quantitative image products, which can be used into specific processing algorithms. By appropriately defining the interfaces to the ground segment, the customers can use the same set of services to request basic and intermediate data products.

Key Drivers in the Ground Segment Definition The definition of the ground segment architecture will consider the following drivers:  Identified products in previous work package;  Smart selection of spectral, spatial, radiometric and temporal characteristics;  Anticipated data rates and data volumes;  Required turnaround times;  Degree of automation for standard products. The segment must focus on acquisition/processing functionality, which supports applications, which have been identified previously.

Modular Ground Segment Decomposition The ground segment can be decomposed into a set of coupled modular systems which provide the infrastructure and services required to support the space and service segment. By appropriately defining the system boundaries, this decomposition can take into account individual and combined missions.

OHTS The Order Handling and Tasking System (OHTS) is the “front-end” to the mission in terms of the products and services that a customer sees. It is responsible for responding to the user’s needs. The system performs the following functions:

 Internet interface into mission products and services;  Customer order handling;  Mission and product catalogue;  Acquisition planning & tasking;

 Product packaging and delivery;  Customer information;  Customer billing information;  Financial services;

MOS The Mission Operation System (MOS) provides the primary interface from the ground segment to the space segment. The system performs the following functions:

 Mission planning;  Final spacecraft constraint checking;  Spacecraft command and control infrastructure;  Spacecraft health monitoring;  Orbit determination & maintenance;  Pay-load mode and calibration commands and maintenance.

DAS The Data Acquisition System (DAS) provides the primary interface from the space segment to the ground segment. The system is responsible for the following functions:

 Satellite data reception;  Housekeeping data and spacecraft telemetry management;  Routine housekeeping data to the MOS  Routing imagery and spacecraft telemetry data to the DPAS

DPAS The Data Processing and Archiving System (DPAS) is responsible for transforming raw image data to quantitative data products, which can be feed to the application service segment. The system provides the following functionality:

 Decryption and decompression raw of image data;  Geometric and radiometric preprocessing of raw imagery;  Catalogue metadata production;  Image and calibration archive maintenance  Storing and retrieving intermediate products upon customer demand  Storing and retrieving calibration and ancillary data

The core ground segment products will be defined so as to meet the operational needs of the service.

5.5 CONCLUSIONS AND RECOMMENDATIONS

At the final review of the study conclusions and recommendations will be summarised (WP4200). The final report will be co-ordinated by KNMI and it will contain contributions from all workpackage leaders. Given the expected performance of the derived mission concepts such as these have been defined in WP3000, and for which the requirements were set in WP1000 and WP2000, in the final report

of the study an assessment will be made on the urgency of the considered applications. The derived mission concepts will be further evaluated by the full consortium on societal and economic aspects and recommendations will be made. Also a quick survey will be performed on the potential for national contributions to the derived missions.

6 RELATED PROJECTS

This section gives an alphabetic list of some complementary projects in which the consortium of this proposal participates. For each of the projects a brief description is given.

DAEDALUS The goals of the DAEDALUS project are to advise on the optimum use of aerosol in-situ, ground- based and satellite remote sensing data to meet the users needs, to deliver data and information to the users, to make proposals for aerosol monitoring as part of the European capacity to be established for GMES and to develop the methodologies necessary for delivering operational aerosol products. Specific objectives are:  to compile existing aerosol data relevant to tropospheric and stratospheric aerosol monitoring,  to foster the dialogue between users and providers of aerosol data, and assess the users needs at the European level in terms of tropospheric and stratospheric aerosol properties,  to match the available aerosol data products with the information needed by users,  to make proposals for a sustainable monitoring infrastructure in order to meet the users needs, including an assessment of the scientific, technical and institutional efforts needed, in particular regarding operational aerosol products, and  to improve methodologies for making optimal use of satellite data and for assimilating aerosol data in regional and global transport, and numerical weather prediction models.

EVERGREEN The EU project EVERGREEN (EnVisat for Environmental Regulation of GREENhouse gases) main objective is the employment of the ENVISAT satellite measurements to improve the greenhouse gas flux estimates derived from theoretical modelling, surface and airborne measurements. The focus will be on methane and carbon monoxide, but carbon dioxide is included on a best effort basis.

The EU project GOA (GOME Assimilated and validated ozone and NO2 fields for scientific users and for model validation, 2001-2003) comprises the development of retrieval and data assimilation algorithms for ozone and NO2 data from GOME. The project aims to provide long- term series of high-level assimilated GOME data to scientific users.

GOFAP GOme Fast-delivery and value-Added Products (GOFAP, 1997-2001) is a KNMI project within the framework of the ESA Data User Programme. Within this project an operational system has been developed and put into use for near-real time delivery (i.e. within 3 hours after observation) of GOME total ozone columns and stratospheric ozone profiles. The ozone columns have been validated through an extended pole-to-pole comparison with ground-based ozone data from NDSC stations by BIRA-IASB. In order to deliver high-quality products several improvements in the level 0-1 processing have been implemented. Assimilated ozone fields and ozone forecasts are provided via the GOFAP web page.

Ozone-SAF The EUMETSAT ozone satellite application facility (Ozone-SAF) project has been established in 1997. The Ozone-SAF project prepares for ozone and other trace gas retrievals for the METOP and MSG satellites. For GOME-2 on board METOP-1, 2 and 3 KNMI has the responsibility for the retrieval of the ozone profile and aerosol operational data products, and for the validation of the total ozone product using data-assimilation.

The EU QUILT project (“Quantification and Interpretation of Long Term UV-Visible Observations of the Stratosphere”, Framework 5 project co-ordinated by NILU, 2001-2003) is aimed at the development of optimised observation capabilities in Europe for long-term monitoring of stratospheric compounds related to ozone-depletion. An integrated approach is being developed, based on UV-visible observations from existing ground-based, balloon and satellite platforms, assisted by state-of-the-art multi-dimensional models.

SCIAVALIG (NIVR, Dutch funding) SCIAVALIG, chaired by KNMI, co-ordinates the SCIAMACHY validation of level 1 and level 2 products. Therefore, access to SCIAMACHY data is possible during the commissioning phase of the instrument.

TEMIS TEMIS is the continuation of the GOFAP project within the ESA Data User Program (see above).

TROPOSAT TROPOSAT is a project to study the use and usability of satellite data for tropospheric research. The formal aim is to determine two- and three-dimensional distributions and time series of trace gases and other parameters in the troposphere and so facilitate future research and environmental monitoring on regional and global scales.