The Committee on Earth Observation Satellites (CEOS)

At the tenth Conference of the Parties (COP-10) to the United Nations Framework Convention on Climate Change (UNFCCC), the Parties that support space agencies were invited to provide a response to the needs expressed in the Global Climate Observing System (GCOS) Implementation Plan (IP). CEOS, as the primary international forum for coordination of space-based Earth observations, agreed to respond. At COP-11, an initial document outlined the CEOS approach. This report, Satellite Observation of the Climate System: The Committee on Earth Observation Satellites Response to the Global Climate Observing System (GCOS) Implementation Plan (IP), regards the adequacy of past, present and future satellite measurements in support of GCOS.

The CEOS report specifically responds to UNFCCC needs for satellite observations and shows the opportunity for space agencies to review the way in which multi-agency cooperation on climaterelated observations is prioritised, agreed, funded, implemented, and monitored. In its report, CEOS identifies what can be achieved by better coordination of existing and future capabilities, as well as improvements requiring additional resources and/or mandates beyond the present capacity of space agencies. The report is intended to initiate action and assist the Parties in advising and commenting on the planning actions within the agencies.

Based on sea height anomaly data from space-based radar altimeters, this NOAA/Atlantic Oceanographic and Meteorological Laboratory (AOML) image represents upper-ocean thermal conditions during Hurricane Frances, used to calculate the likelihood of the storm intensity changing as it passed over warm water masses that sea surface temperature measurements could not detect (ESA)

The report notes that satellites provide vital means of obtaining observations of the climate system from a global perspective, and that a detailed global climate record for the future will not be possible without a major, sustained, satellite component. It further notes that for satellite data to contribute fully and effectively to the determination of long-term records, the system must be implemented and operated so data are climatically accurate and homogeneous. To this end, the GCOS Climate Monitoring Principles (GCMPs) call for continuity of observations, calibration and validation of observations, access to data, and robust research and development programs.

Comprehensive Data Record

Although almost all Earth-observing satellite systems were not specifically designed for climate monitoring, space agency efforts have gathered a remarkably comprehensive climate data record as a basis for better understanding the Earth’s climate system. Much has been accomplished, but significant gaps remain in measurement capabilities and their continuity.

Sea Level Trends from Topex-Poseidon (Jan. 1993 - Mar. 2005) Global Mean Sea Level Rise. TOPEX/Poseidon data were used to create this graphic showing global sea level trends between 1993 and 2005 (Laboratoire d'Etudes de Géodésie et d'Océanographie Spatiales (LEGOS) / Centre National d'Etudes Spatiales (CNES)).

CEOS agencies operate satellites that collect data from three domains – atmospheric, oceanic, and terrestrial – which establish key Earth parameters (Essential Climate Variables, ECVs). For each domain CEOS has validated the satellite component of the Plan and offered detailed analyses and corresponding actions from six key categories:

• Ensuring continuity of climate-relevant satellite measurements;

• Taking a systematic approach to generating fundamental climate data records;

• Preserving climate data records;

• Ensuring access to climate data products

• Coordinating international communities and interaction with users; and

• Addressing future measurement needs.

CEOS has also identified opportunities for meeting the additional requirements by reprocessing historical data collections, improving data continuity, and moving measurements from research to operations. CEOS agencies recognise the need to ensure adequate retrieval, processing, archiving, and provision of historical satellite data and will investigate methods for doing so.

Constellation of Satellites

CEOS has launched an initiative to develop guidelines and criteria for agencies to implement groups, or “Constellations” of satellites and their associated ground support systems. These Constellations will work in a coordinated manner to enable more cost-effective missions and allow valuable contributions from the range of systems. Current efforts include: atmospheric composition, global precipitation, land surface imaging and sea level topography.

Since the UNFCCC was adopted, government recognition and public awareness of climate change has increased substantially. GCOS, with its partners, has developed a credible Plan that, if implemented, will improve understanding of climate change. The Global Earth Observation System of Systems (GEOSS) has given more attention to the nine Societal Benefit Areas (SBAs), including that of climate. Meeting the UNFCCC climate needs will also contribute significantly to most, if not all, of the other SBAs. CEOS recognises that not all Parties fully benefit from satellite access and will prioritise improving such access.

Way Forward

CEOS proposes the following:

The Parties are invited to note the many wide-ranging and challenging actions identified in the report. Agencies will work with their governing bodies to secure the additional resources required. CEOS will, with GCOS, continue to strengthen the extremely productive communication and cooperation.

CEOS notes the encouragement of past UNFCCC decisions and welcomes feedback from the Parties on the CEOS response to the Plan. CEOS also understands the importance of reporting to the UNFCCC on systematic observations and progress, and, if requested by thes Parties, would be willing to do so.

Both satellite and in situ data are required to better monitor, characterise, and predict changes in the Earth system. While in situ measurements are essential and largely measure what cannot be measured from satellites, Earth-observation satellites are the only realistic means to obtain the necessary global coverage, and with well-calibrated measurements will become the single most important contribution to global climate observations.

W: www.ceos.org