The microwave radiometer aboard ERS-1.1. Characteristics and performances

The microwave radiometer onboard ERS-1 has two channels at 23.8 and 35.6 GHz. It is a nadir pointing sensor, which is aimed at the correction of the altimeter tropospheric path delay. The characteristics of the instrument are described, and its performance is established from ground calibration results. Using early data obtained after launch, the in-flight engineering calibration is presented, showing that the radiometer behavior is nominal. The gain stability permits noise reduction, and the radiometer performance appears to be as good as specified. >