|GLOBAL CLIMATE OBSERVING SYSTEM
ESSENTIAL CLIMATE VARIABLE - Other long‐lived greenhouse gases
|Domain||Atmospheric||Description||The ECV “Other long-lived greenhouse gases” refers to a set of gases additional to carbon dioxide and methane that are classified as having atmospheric lifetimes of at least a few years. The term “well-mixed” is also used to characterise them and may be preferred. Stratospheric distributions of these species may nevertheless exhibit quite substantial spatial variations, either because of the multi-year time scale of much of the transport and mixing across the region or because of localized photochemical reactions. It is important to measure this set of gases because some already contribute appreciably to the radiative forcing of climate change due to increases in concentration since the pre-industrial era, whilst others are increasing rapidly in concentration and have a strong potential to enhance warming if their emission continues unchecked. Some also have to be monitored because they deplete ozone in the stratosphere. This has to continue for the species that are subject to emission controls under the Montreal Protocol, as their lifetimes are long.
The set of gases include nitrous oxide (N2O), sulphur hexafluoride (SF6) and groups of species categorised as chlorofluorocarbon (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs) and perfluorocarbons (PFCs). All have anthropogenic sources and none has a substantial tropospheric sink. Only N2O has a significant natural source. N2O, the CFCs and the HCFCs are the species involved in ozone depletion. [GCOS-195 4.7.3]
|Full Name||Other long‐lived greenhouse gases
|Satellite Signficant Contribution||Yes
*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.
|Description||Who||Time Frame||Performance Indicator||Cost 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.||Ongoing||Dataflow to archive and analyses centres||Dataflow 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).
|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 http://www.ace.uwaterloo.ca/index.html
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:
the only limb sounding instruments will be:
- 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,
Specific Deliverable #2
- 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).
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.
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: http://www.wmo.int/pages/prog/arep/gaw/gaw_home_en.html
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: http://ceos.org/document_management/Publications/WGClimate_CEOS-Strategy-for-Carbon- 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
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.
- 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.
All developments are taking place in close collaboration with the NASA-ACOS team and the GOSAT teams at NIES and JAXA.