Status of the Global Observing System for Climate October 2015 GCOS-195 Final version, subject to copy-editing Status of the Global Observing System for Climate 1 Status of the Global Observing System for Climate October 2015 GCOS-195 Final version, subject to copy-editing Final version, subject to copy-editing October 2015 Status of the Global Observing System for Climate 2 Final version, subject to copy-editing October 2015 Status of the Global Observing System for Climate 3 © World Meteorological Organization, 2015 NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. 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Final version, subject to copy-editing October 2015 Status of the Global Observing System for Climate 4 Contents Foreword ................................................................................................................................................. 9 Background and outline ........................................................................................................................11 Overall conclusions ................................................................................................................................12 1 Introduction and background ........................................................................................................17 1.1 The context and purpose of this report ...................................................................................17 1.2 The scope and concept of the global observing system for climate ........................................17 1.3 The cycle of assessment and identification of requirements ..................................................18 1.4 The outline, basis and limits of this report ...............................................................................19 2 Climate Observation ......................................................................................................................20 2.1 The need for systematic observation .......................................................................................20 2.2 The nature of climate observation ...........................................................................................22 2.3 Implementing agencies and international coordination ..........................................................23 2.3.1 National and regional agents for implementation ............................................................23 2.3.2 International arrangements for coordination and assessment .........................................24 2.3.3 The principal atmospheric, oceanic and terrestrial observing systems ............................26 2.4 Tiered observing networks and constellations ........................................................................27 2.5 The Essential Climate Variables................................................................................................28 2.6 Climate-system cycles ..............................................................................................................29 3 Overarching and cross-cutting elements .......................................................................................30 3.1 Planning and reporting .............................................................................................................30 3.2 Towards sustained networks and systems ...............................................................................31 3.3 International support for critical networks ..............................................................................32 3.4 Space-based observation .........................................................................................................32 3.4.1 Introduction .......................................................................................................................32 3.4.2 Sustained satellite observing systems for weather and climate .......................................33 3.4.3 The European Copernicus programme ..............................................................................35 3.4.4 Missions for research and development, and the challenges of continuity .....................36 3.4.5 Data monitoring .................................................................................................................38 3.4.6 Fundamental forms of climate data records .....................................................................39 3.4.7 Inter-calibration of data records ........................................................................................40 3.4.8 Data archives .....................................................................................................................41 3.5 Generation of data products ....................................................................................................42 3.6 Reanalysis .................................................................................................................................43 Final version, subject to copy-editing October 2015 Status of the Global Observing System for Climate 5 3.7 Recovery of instrumental data .................................................................................................45 3.8 Proxy reconstructions of past climates ....................................................................................47 3.9 Data management ....................................................................................................................48 3.10 Climate impacts ........................................................................................................................49 4 Atmospheric observation ..............................................................................................................50 4.1 Introduction..............................................................................................................................50 4.2 Meteorological surface networks ............................................................................................51 4.2.1 Comprehensive surface networks .....................................................................................52 4.2.2 Baseline and reference networks ......................................................................................56 4.2.3 Data archives .....................................................................................................................57 4.3 Surface variables ......................................................................................................................58 4.3.1 Air temperature .................................................................................................................58 4.3.2 Wind speed and direction ..................................................................................................62 4.3.3 Water vapour .....................................................................................................................63 4.3.4 Pressure .............................................................................................................................65 4.3.5 Precipitation .......................................................................................................................68 4.3.6 Surface radiation budget ...................................................................................................71 4.4 Meteorological upper-air networks .........................................................................................73 4.4.1 The comprehensive radiosonde network ..........................................................................74 4.4.2 Observations from aircraft ................................................................................................76 4.4.3 Baseline upper-air network ...............................................................................................77 4.4.4 Reference upper-air network ............................................................................................79 4.4.5 Data archives .....................................................................................................................79 4.5 Upper-air variables ...................................................................................................................80 4.5.1 Temperature ......................................................................................................................80 4.5.2 Wind speed and direction ..................................................................................................83 4.5.3 Water vapour .....................................................................................................................85 4.5.4 Cloud Properties ................................................................................................................88 4.5.5 Earth radiation budget