Polarimetric radiometer configurations

Ocean wind speed and direction can be assessed with a polarimetric radiometer system measuring the full set of Stokes parameters. The first and second Stokes parameters are the sum and difference of the usual vertical and horizontal brightness temperatures. The third and forth Stokes parameters can be found either by cross correlating the received vertical and horizontal electrical fields, or they can be found by a combination of properly polarized brightness temperature measurements. These considerations directly point at two fundamentally different ways of implementing the polarimetric radiometer system. Paramount issues are instrument stability and sensitivity as well as the trade-off between increased microwave hardware complexity and fast digital correlator circuitry. Also, within each fundamental category there are significant trade-offs. Based on such considerations a second generation airborne, imaging, polarimetric radiometer system is presently in its development phase. The design of the system is discussed.