GCOS Essentioal Climate Variables Matrix

Facilitating Access to Global Observing Systems Data and Information

GCOS Essential Climate Variables

(under development)

The Essential Climate Variables (ECVs) are required to support the work of the UNFCCC and the IPCC. All ECVs are technically and economically feasible for systematic observation. It is these variables for which international exchange is required for both current and historical observations. Additional variables required for research purposes are not included in this table. It is emphasized that the ordering within the table is simply for convenience and is not an indicator of relative priority. Currently, there are 44 ECVs plus soil moisture recognized as an emerging ECV. (from the WMO GCOS web site) (Reference document)

Atmospheric	Ocean	Terrestrial [2]
Surface	Surface	River Discharge
Air temperature	Sea-Surface Temperature	Water Use
Precipitation	Sea-Surface Salinity	Ground Water
Air Pressure	Sea Level	Lake Levels
Surface Radiation Budget	Sea State	Snow Cover
Wind Speed and Direction	Sea Ice	Glacier and ice caps
Water Vapour	Current	Permafrost and Seasonally-Frozen Ground
Upper-Air	Ocean Color	Albedo
Earth Radiation Budget	Carbon Dioxide Partial Pressure	Land Cover (including vegetation type)
Upper-air temperature	Sub-surface	Fraction of absorbed photosynthetically active radiation (fAPAR)
Wind Speed and Direction	Temperature	Leaf Area Index (LAI)
Water Vapour	Salinity	Biomass
Cloud Properties	Current	Fire Disturbance
Atmospheric Composition	Nutrients	Soil Moisture [3]
Carbon Dioxide	Carbon
Methane	Ocean tracers
Ozone	Phytoplankton
Nitrous Oxide
Chlorofluorocarbons (CFCs)
Hydrochlorofluorocarbons (HCFCs)
Hydrofluorocarbons (HFCs)
Sulphur hexafluroride (SF6)
Perfluorocarbons (PFCs)
Aerosol Properties

[2] Includes runoff (m3 s-1), ground water extraction rates (m3 yr-1) and location, snow cover extent (km2) and duration, snow depth (cm), glacier/ice cap inventory and mass balance (kg m-2 yr-1), glacier length (m), ice sheet mass balance (kg m-2 yr-1) and extent (km2), permafrost extent (km2), temperature profiles and active layer thickness, above ground biomass (t/ha), burnt area (ha), date and location of active fire, burn efficiency (%vegetation burned/unit area).

[3] Recognized as an emerging Essential Climate Variable (not part of the 44).