Almost whole of the year, mid-to high-latitude regions are covered with snow.
The snowpack undergoes several cycles of melting and refreezing throughout
the year, which influences the weather conditions, and surface and subsurface
water. The capability of microwaves to penetrate snow layer and respond to
variations in subsurface properties along with all-weather and all-time
observational capabilities make Microwave Remote Sensing an useful tool to
monitor snowpack properties on global scale. The microwave portion of
electromagnetic spectrum is advantageous additionally because of the large
difference in the dielectric constant of liquid and frozen water, which causes a
strong variation in the observed microwave signal when liquid water is present.
In order to study the microwave remote sensing response over snow covered
areas, detailed numerical calculations have been carried out over various
two-layered and multi-layered models representative of such areas. The results
show that the microwave remote sensing can be used to map the snow cover
extent, to classify snow types, to estimate snow thickness, to detect onset of
snowmelt, to estimate the free liquid water content of snow, to monitor the
roughness of snow surfaces, and to estimate the lake ice thickness. The
detailed discussion of the results have been presented in view of the proper
selection of operating parameters of microwave remote sensors for the mapping
of snow covered regions.