| Accumulated precipitation (over 24 h) | 4 - fair | Poor time sampling.. Time sampling to be interpolated by GEO. | MW channels around 10, 19, 23 and 37 GHz, with high spatial resolution |
| Biomass | 3 - high | Index only.. Coarse spatial resolution. | Derived from differential effect of vegetation across MW frequencies around 7, 10 and 19 GHz |
| Cloud liquid water (CLW) | 3 - high | No specific limitation. | MW channels around 37 GHz |
| Cloud liquid water (CLW) total column | 3 - high | No specific limitation. | MW channels around 37 GHz |
| Land surface temperature | 5 - marginal | Coarse spatial resolution. | MW channels with more frequencies around 7 and 10 GHz to reduce sensitivity to radio-frequency interferences |
| Long-wave Earth surface emissivity | 3 - high | Long time series needed. | MW channels around 7, 10, 19 and 37 GHz. Emissivity across this MW range inferred by statistical analysis |
| Precipitation intensity at surface (liquid or solid) | 4 - fair | No specific limitation. | MW channels around 10, 19, 23, and 37 GHz. High spatial resolution consistent with the scale of precipitation |
| Sea surface temperature* | 2 - very high | No specific limitation. | MW channels with more frequencies around 7 and 10 GHz to reduce sensitivity to radio-frequency interferences |
| Sea-ice cover* | 2 - very high | No specific limitation. | MW channels around 7, 10, 19 and 37 GHz, with high spatial resolution for accurate contour detection |
| Sea-ice type | 5 - marginal | No specific limitation. | MW channels around 7, 10, 19 and 37 GHz. Type interpreted as age/roughness |
| Snow cover | 2 - very high | Coarse spatial resolution. | MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields |
| Snow status (wet/dry) | 1 - primary | Coarse spatial resolution. | MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields |
| Snow water equivalent | 1 - primary | Coarse spatial resolution.. Ground stations network needed. | MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields |
| Soil moisture (in the roots region) | 4 - fair | Coarse spatial resolution.. Affected by vegetation. | MW channels around 7 GHz. Assimilation process required |
| Soil moisture at surface | 3 - high | Coarse spatial resolution.. Affected by vegetation. | MW channels around 7 and 10 GHz |
| Integrated Water Vapour (IWV) | 1 - primary | No specific limitation. | Use of water vapour band around 23 GHz with dual polarisation. High resolution useful for tomography |
| Wind speed (near surface)* | 2 - very high | Over sea only. | MW channels around 7, 10, 19 and 37 GHz |
| Wind vector (near surface)* | 3 - high | Over sea only. | MW channels for 3 or 4 Stokes parameters at frequencies around 10, 19 and 37 GHz |
Instrument: WindSat