Selection of optimum frequencies for atmospheric electric path length measurement by satellite-borne microwave radiometers

Numerical experiments using regressions by leaps and hounds have been performed to determine the optimum frequencies for satellite-borne microwave radiometers to estimate atmospheric electrical path length over the sea. The frequency range 5-40 GHz was searched. The effect of surface wind speed, sea surface temperature, and clouds was considered in the optimum frequency selection. Our analysis indicates that
\sim 0.6
-cm rms accuracy is possible for one-way path length measurement using a proper pair of frequencies. The best two-channel subset selected by the leaps and bounds technique is [16.0, 21.0] GHz.