6.5
Polarimetric Microwave Radiometer Architectures and Characterization for Spaceborne Mapping of Ocean Surface Wind Vector
Currently, the Special Sensor Microwave Imager Sounder (SSMIS) instrument built by NGES in the Azusa campus provides global wind speed data to the users. The principle of operation makes use of the 1st and 2nd Stokes parameters of the elliptically polarized microwave emissions from the sea surface. The elliptical polarization is the result of wind-induced water ripples which appear smoother in the crosswind direction and rougher in the up- or downwind direction. In order to obtain information about wind direction, knowledge of the 3rd and 4th Stokes parameters is necessary.
In this presentation, we will review the principles of microwave polarimetry and its applications, followed by a description of several polarimetric receiver architectures for wind direction detection. We will describe how these receiver architectures can conceptually be incorporated into the present SSMIS system while at the same time preserving most of the existing capabilities. The advantages of such an approach are low risk, lower cost, and better timeliness in filling the OSWV capability gap.