It maximizes the radiometric integrity of the original brightness temperature values, maintains high spatial and temporal precision, and involves no averaging of original swath data. The grid and projection scheme are independent of the satellite sensor or data type. The EASE-grid is currently provided in a full global cylindrical equal area projection and azimuthal equal area, full Northern and Southern Hemisphere projections. The basic microwave products are daily gridded brightness temperatures for both polar regions and full global coverage in the EASE-grid format. However, no current algorithms are appropriate for global-scale SWE retrievals.
Progress requires understanding the errors currently found in regional algorithms.
Quantitative relationships between multichannel microwave signatures and surface measurements are being established. Digital image comparison for multiyear data will show whether any differences are systematic, and if so, whether the regions with greatest consistent errors are related to topography, vegetation, or snow-climate conditions. Regression of microwave signatures on station data will be used to derive optimal regional relationships as the basis for global mapping. The principal drawback for surface parameter retrievals is cloud cover. These times are imposed by the constraints of maximum coverage at low scan angle, and the orbital drift.