Accurate microwave radiometers for altimeter missions

This paper is dedicated to the particular case of the radiometers dedicated to the altimer path delay correction. The constraints on the calibration and stability of these instruments are therefore particularly strong. Wepresent here our methodology for the calibration/validation of ERS½ and ENVISAT microwave radiometers as well as the different methods we use to check the quality/stability of the brightness temperatures and of the path delay.