SeaWinds radiometer (SRad) brightness temperature calibration and validation

NASA´s SeaWinds scatterometer, on Japan´s ADEOS-II satellite, is a special purpose radar remote sensor used to measure ocean surface wind vector (speed and direction). The paper presents a novel use of this instrument as a SeaWinds radiometer (SRad) to measure the ocean microwave emissions (brightness temperature). The derivation of the SRad radiometric transfer function is presented, which is used to calculate the apparent brightness temperature collected simultaneously with the radar scattering measurement. Results are presented for the on-orbit calibration and validation of the SRad brightness temperature algorithm performed using simultaneous measurements from the advanced microwave scanning radiometer (AMSR) also on the ADEOS-II.