Comparative analysis of the zenith and off-zenith retrieved results from microwave radiometer in rain and snow weather conditions

In order to test the improvement of results in the off-zenith directions under rain and snow weather, the retrieved temperature, humidity,vapor density and liquid water density profiles from MP-3000A microwave radiometer (MWR) of the zenith and off-zenith observations from 17 to 18 February 2014 are studied by comparing them with the Thies Clima laser precipitation monitor，L-band sounding data and precipitable water retrieved from GPS-MET from Wuhan station. Results are as follows. (1) If observed at off-zenith, the brightness temperature signal saturation phenomenon at K and V bands can be eliminated effectively. Brightness temperature varies with rainfall intensity. (2)The correlation coefficient between the MWR product retrieved in off-zenith observation and sounding is better. (3) Although precipitable water vapor (PWV) retrieved in off-zenith observation is larger than the GPS/PWV, their trends are consistent. In contrast, there is a clear jump for the result in zenith observation after precipitation occurs. (4) There is a good corresponding relationship between the accumulation of cloud liquid water retrieved in off-zenith observation and the enhancement precipitation intensity.