Retrieval of liquid water content profiles in mixed and rainy stratus clouds by combing cloud radar and microwave radiometer

Because of the influence of precipitation and ice particles, the error in liquid water content (LWC) retrieval is big when exclusively using cloud radar data. The error of LWC resulted from microwave radiometer is also big due to not having information on vertical cloud structure. On the basis of retrieving LWC profile for warm clouds by combing cloud radar and microwave radiometer, and incorporating the relationships between echo intensity and precipitation particles, and between temperature and ice particles, a particle distribution model is established, and a method to retrieve LWC in mixed rainy stratus clouds by combing the echo intensity of cloud radar and the liquid water path (LWP) of microwave radiometer is put forward. The stability and rationality of the algorithm are analyzed based on precipitation data on June 6, 2014 and June 7, 2014. The conclusion is as follows. (1) Compared to the method that uses a single Z-LWC relationship to retrieve LWC profile, this algorithm is more reasonable, because it rejects the influence by ice particles to the echo intensity, and uses cloud and precipitation particles separately to retrieve LWC profiles. (2) In the 7 parameters that affect the result of this algorithm, a2 and b2 in the Z-LWC relationship for precipitation have greater impact (20~30%) than the others (less than 5%). This shows a good stability of this algorithm. (3) Com-pared to LWC profiles from microwave radiometer alone, the LWC profiles retrieved from this algorithm are more reasonable.