The Study Of The Properties Of Clouds Over Huai River Basin Based On Spaceborne-based Radar And Ground-based Radar

The CloudSat data products (2B-GEOPROF) provided by 94GHz spaceborne radar from January 2007 to February 2010 were used to study the occurrence frequency, the cloud top height and the liquid water path(LWP) of different kinds of clouds over Huai River basin, then the ARM AMF radar products provided by 94GHz ground-based radar were used to study the liquid water content distribution characteristics of clouds over Shouxian,An Hui in this paper. The main results show that:The seasonal distribution characteristics of the occurrence frequency of ice phase clouds is similar to the total clouds’,the highest in the summer and the lowest in autumn;the occurrence frequency of warm clouds is the highest in the autumn and the lowest in winter; the occurrence frequency of mixed phase clouds and the cloud top height have remarkable seasonal distribution characteristics, the highest in the summer and the lowest in winter;The three kinds of clouds have the same seasonal distribution characteristics as the 0° C layer height. Then, the differential reflectivity of Shouxian,AnHui shows that:the radar reflectivity factor of surface in the morning of the day when there is no precipitation throughout the day is bigger than the one in the afternoon and evening; where there are clouds,with the radar reflectivity factor increases,the differential reflectivity also increases quickly. The bigger the cloud thickness is,the bigger the area of the big value of the differential reflectivity is.For double clouds, the biggest radar reflectivity factor of the under clouds is bigger than which of the upper clouds, and the differential reflectivity cannot describe the characteristics.The retrieval method of using the CloudSat data to derived LWC when the temperature between-20°C and 0° C were amended, the LWP retrieved by the amended retrieval method is more close to the ground observation. The retrieved LWP of the mixed phase clouds and the warm clouds have the same seasonal distribution characteristics, the highest in summer and fall, the lowest in winter and spring. The LWP of the mixed phase clouds is three times of the warm clouds.With the LWP increasing, the range of radar reflectivity and their altitude is more and more concentrated, the high value of the mixed phase clouds’occurrence frequency in Lower troposphere increases with the LWP value increasing; the maximum value of radar reflectivity corresponding to them has remarkable seasonal distribution characteristics, which is relative to the height of 0° C layer in mixed phase clouds. The start precipitation time of the mixed phase clouds is later than the warm clouds, and the duration time is longer than warm clouds.The ARM AMF radar reflectivity factor is used with the modified CloudSat method to retrieve the LWC. The study found that:in autumn and winter, the warm clouds is little, and the cloud particle is mostly drizzle particles and rain particles in the mixed phase clouds.which appear in the low height. Compared with the other methods, the LWC derived from the modified CloudSat method is similar to the others when the temperature of the clouds is under -5° C.but when the cloud temperature of the clouds is beyond -5° C, the LWC derived from the other methods are much more different.