Microwave polarimetric measurements of the sea surface brightness temperature from a blimp during the Coastal Ocean Probing Experiment (COPE)

Experimental data obtained with a microwave dual‐frequency radiometer at 23.87 and 31.65 GHz and a polarimeter at 37.0 GHz installed on a blimp during the Coastal Ocean Probing Experiment in 1995 are analyzed. Observations of the downwelling atmospheric radiation as a function of angle were used to achieve a highly accurate absolute calibration. The dependence of the sea surface brightness temperature on nadir and azimuthal angles is considered. The experimental data are compared with theoretical calculations based on several models of sea wave spectra. Models proposed by Romeiser et al. [1997] and Elfouhaily et al. [1997] fit well to the COPE azimuthal measurements and data averaged over azimuthal angle are in between of values predicted by spectrum models by Apel [1994] and Elfouhaily et al. [1997]. The conclusion is made about high sensitivity of the polarized radiometric measurements to parameters of gravity‐capillary spectrum.