Microwave radiometer experiments at a marine observation tower.

Abstract

Observations of the brightness temperature of the sea surface were carried out in 1982 and 1983, using the Bread Board Model (BBM) of the Microwave Scanning Radiometer (MSR) which will be on board MOS-1 in early 1987. The observational results show that at 23 GHz, one of the two frequencies selected for MSR, the brightness temperature observed with MSR is explained by a radiative model with an error smaller than 5 degrees. At 31 GHz, the other frequency of MSR, the error becomes larger than 10 degrees. At frequencies used for MSR, a linear regression method, applied to the surface water vapor pressure and the surface wind speed, gives the result that signs of coefficients of the surface wind effect are almost all negative. Instead of this method, two separate approaches give them 0.4 and 0.8 K/m/s at 31 GHz in the horizontal polarization. One is to seek an example in which the surface wind increases greatly within a short period, and the other is to eliminate the water vapor effect from the observed temperature, using the coefficients resulting from the radiative model.