The Principal Investigators will develop physically based microwave scattering, emission, and absorption models that are useful for active and passive microwave polarimetric remote sensing of the snow properties of the Greenland ice sheet (GIS). The models will establish the quantitative relations between the microwave signatures and the physical parameters of the snow of GIS such as roughness rms (root mean square) height, spectrum of roughness, azimuthal asymmetry of roughness profiles, multilayering structures, snow densities and snow grain sizes. The existing satellite missions include QuikScat, SSMI, AMSR and WINDSAT and future possible satellite missions include CoReH2O and CLPP. They will develop quantitative relations by using rigorous electromagnetic theory of microwave interactions. These will be useful to relate quantitatively the physical parameters of the snow properties of the GIS to the quantitative descriptions of the geophysical and climate processes. The electromagnetic models of microwave interactions have been successfully applied to terrestrial snow. However, such models have not been applied to the GIS that have distinct features of large snow thicknesses, multilayering structures and azimuthal asymmetry of surface roughness created by sastrugi. They will develop electromagnetic models that incorporate these features. They will study random rough surface scattering that have azimuthal asymmetry, volume scattering due to snow grains, and reflections due to multilayering. The Principal Investigators will incorporate ground truth measurements of physical parameters in the microwave models. The microwave models will be applied to QuikScat, SSMI, AMSR and WINDSAT satellite data. They will particularly emphasize on WINDSAT data. Intellectual Merit : The Principal Investigators will develop electromagnetic models that relate the microwave signatures quantitatively to physical parameters of snow in Greenland such as roughness, layering, snow grain sizes and azimuthal asymmetry. The knowledge of such physical parameters facilitates the use of microwave remote sensing signatures in models of geophysical and climate processes in Greenland. The ventilation affects the sublimation rate and vapor transport that play key roles in microscopic processes of crystal change and macroscopic effects of mass loss and species redistribution. Quantitatively relating the microwave signatures to snow grain sizes can quantity such effects of ventilation. Broader Impacts:. The earth monitoring research is an on-going dynamic endeavor that requires participation of younger generation of students, scientists, and engineers. Our research will help educate and train students that participate in this proposed work to become familiar with remote sensing, and earth science applications. In the broader context of electromagnetic theory, the multiple scattering of electromagnetic waves of combined volume and surface scattering in the presence of layering and azimuthal asymmetry have not been studied before. Thus the results of electromagnetic theory for such problems can be used in other geoscience and engineering applications.
