The Microwave Radiometer (MWR) or Microwave Sounder (MWS) (more info here) is one of the instruments aboard the European Remote Sensing Satellites ERS-1 (more info here and here) and ERS-2 (more info here and here). The main purpose of the MWR is the measurement of the tropospheric path delay for the altimeter through the measurements of the atmospheric integrated water vapor content and the estimate of the attenuation of the altimetric signal by the liquid water content of the clouds.
