THE CEOS DATABASE : Missions, Instruments and Measurements
DomainAtmosphericDescriptionMethane (CH4) is the second most significant of the greenhouse gases that have increased in concentration in the atmosphere directly due to human activities, from the viewpoint of the radiative forcing of climate change. Its mole fraction has increased from a pre-industrial level of around 700 ppb to current levels that are around 1900 ppb at high northern latitudes and approach 1800 ppb at the South Pole. [GCOS-195 4.7.2]
Full NameMethane
Satellite Signficant ContributionYes
GCOS Actions
DescriptionWhoTime FramePerformance IndicatorCost Implications
Establish long-term limb-scanning satellite measurement of profiles of water vapour, ozone and other important species from the UT/LS up to 50 km.Space agencies, in conjunction with WMO GAW.Ongoing, with urgency in initial planning to minimize data gap.Continuity of UT/LS and upper stratospheric data records.100-300M US$ (including mission costs) (Mainly by Annex-I Parties).
Maintain and enhance the WMO GAW Global Atmospheric CO2 and CH4 Monitoring Networks as major contributions to the GCOS Comprehensive Networks for CO2 and CH4.Parties’ national services, research agencies, and space agencies, under the guidance of WMO GAW and its Scientific Advisory Group for Greenhouse Gases, in cooperation with the AOPC.OngoingDataflow to archive and analyses centresDataflow to archive and analyses centres
Assess the value of the data provided by current space-based measurements of CO2 and CH4, and develop and implement proposals for follow-on missions accordingly.Parties’ research institutions and space agencies.Urgent, to minimise data gap following GOSAT.Assessment and proposal documents; approval of consequent missions.1-10M US$ initially, increasing with implementation (10% in non-Annex-I Parties).
*GCOS-195 Status Categories: Category A: Action completed, perhaps exceeding reasonable expectations. Very good progress on ongoing tasks. Category B: Action largely completed according to expectation. Good progress on ongoing tasks. Category C: Moderate progress overall, although progress may be good for some part of the action. Category D: Limited progress overall, although progress may be moderate or good for some part of the action. Category E: Very little or no progress, or deterioration rather than progress.
GCOS Products
Related Measurements/
from CEOS DB
A.8.1Retrievals of CO2 and CH4 of sufficient quality to estimate regional sources and sinksTropospheric CO2 column
Tropospheric CO2
Tropospheric CH4 column
Tropospheric CH4
Stratospheric CH4
CH4 Mole Fraction
CEOS Response[A26 (A.9.3, A.5.2, A.8.1)]

2015 Update: The Canadian Space Agency approved the continuation of the SCISAT mission through the end of 2015. The atmospheric chemistry experiment (ACE) Fourier transform infrared spectrometer is unique in its ability to make measurements of upper atmosphere chemistry in the trace gases responsible for ozone depletion. A complete review of this experiment can be found at the following website

Limb Sounding Mission Gap

Participants in the CEOS Atmospheric Chemistry Virtual Constellation meeting of 2014 recognize the significance of the looming gap in limb sounding data. Following the demise of the currently operating but aging instruments:
  • MLS on Aura (microwave emission),
  • SMR (microwave emission) on Odin,
  • OSIRIS (limb scatter UV-Vis-NIR) on Odin,
  • ACE-FTS (solar occultation IR) on SCISAT, and
  • ACE-MAESTRO (solar occultation UV-Vis-NIR) on SCISAT,
the only limb sounding instruments will be:
  • OMPS Limb Profiler on Suomi-NPP (limb scatter UV-Vis-NIR),
  • SAGE-III/ISS (solar occultation & limb scatter UV-Vis-NIR, planned for 2016),
  • OMPS Limb Profiler on JPSS-2 (limb scatter UV-Vis-NIR, planned for ~2021).
Specific Deliverable #2
Maximize use of existing sensors and develop a collaborative framework to advocate and facilitate near-term calibration/validation activities and other coordinated science team planning for near-term space-based missions with limb sounding capability (e.g., to include, but not limited to, Stratospheric Aerosol and Gas Experiment (SAGE) III-ISS and Sentinel 5-Precursor) to maximize scientific output.

[A28 (A.8.1)]

2015 Update: ESA, in cooperation with CEOS WGCV subgroup Atmospheric Composition, NDACC, and TCOON, will support a 2-year field intercomparison of the different type of FTIR instruments used for GHG satellite validation. In addition, an aircraft-based measurement system for GHG is set up in cooperation with University of Bremen. Updated information on in situ networks can be found at the global atmospheric watch website:

[A29 (A.8.1)]

2015 Update: CEOS, as the primary international forum for coordination of space-based Earth observations, recently published a response to the Group on Earth Observation’s (GEO's) Carbon Observation Strategy: the CEOS Strategy for Carbon Observations from Space. The CEOS Strategy details the adequacy of past, present, and planned satellite measurements of carbon in the land, oceans and inland waters, and atmosphere domains to support GEO. Specifically, it identifies important actions CEOS and its Agencies must take to better coordinate existing and future capabilities, as well as challenges that require additional resources and/or mandates beyond the present capacity of CEOS and its member Agencies. The report can be found here: Observations-from-Space_Apr2014.pdf. Because the CEOS Carbon Task Force had been installed as an ad hoc team, the resulting tasks from the action items of the report are now coordinated by the CEOS SIT team. The Carbon Task Force has been closed with fulfillment of its work plan.

GHG_cci has developed and tested multiple algorithms to improve CO2 and CH4 retrieval accuracies and coverage
  • Core products: Column average CO2 and CH4 from SCIAMACHY (2002-2012) and TANSO (2009-2014).
  • Extra column and profile products providing additional modelling constraints, but which have reduced sensitivity to boundary layer CO2 and CH4 concentration are provided from MIPAS, SCIAMACHY, AIRS, ACE-FTS, and IASI.
Additionally, multi-mission ensemble products have been prototyped for CO2. Trials of prototype retrievals for new instruments will be included as part of the project depending on launch dates: OCO-2, TanSat, Sentinel-5P, Merlin, GOSAT-2.

All developments are taking place in close collaboration with the NASA-ACOS team and the GOSAT teams at NIES and JAXA.


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