Although the water stored in the soil is small compared to the amounts in the oceans, changes in the soil water reservoir feed major movements of water through the hydrological cycle. A case study performed over the Canadian Prairie Province Alberta shows that soil moisture information can be retrieved with the ERS scatterometer if the vegetation is moderate. The purpose of the ERS scatterometer is to obtain information on wind speed and wind direction above the oceans and it has been providing valuable information about the ocean circulation since the launch of ERS-1 in July 1991. The spatial resolution is about 50 km.
Soil moisture is one of the most important components of the climate system.
It directly affects the partitioning of energy at the surface between latent and sensible heating. Where soil moisture is high, evaporation will predominate, adding to atmospheric moisture content. Where it is low, the land surface will warm under the influence of radiational heating. Soil moisture information obtained from ERS scatterometer measurements would be ideal for improving the land surface component of GCMs. Approach The ERS scatterometer measures the backscattering coefficient sigma 0 at C band which mainly depends on the incidence angle teta, the moisture content of the soil and the vegetation, the vegetation type and surface roughness.