Cloud macrophysical characteristics in China mainland and east coast from 2006 to 2017 using satellite active remote sensing observations

Using the CloudSat and CALIPSO active remote sensing dataset from 2006 to 2017, this study investigates the spatial and temporal distribution along with vertical distribution of cloud macrophysical characteristics in six study areas over China mainland and east coast (15 degrees-55 degrees N, 70 degrees-140 degrees E). The results show that the cloud top height and cloud base height have significant regional, seasonal and zonal variations. The regional differences in the seasonal average vertical distribution of cloud cover are especially large, which are particularly reflected by the differences of heights with peak value of cloud cover, the curve characteristics of cloud cover with height, and the standard deviation of cloud cover. The cloud spacing, which is the distance between two cloud layers for cloud system with layers no less than 2, is found greater in the ocean area than in the land area and is greater in the low-latitude area than in the high-latitude area. Moreover, with the increase of the number of cloud layers in the cloud system, the cloud spacing decreases gradually. It is worth noting that the frequency distribution of cloud layers is the same as that of cloud spacing. By dividing clouds into eight types according to CloudSat data, the occurrence frequency of different cloud types shows great differences, ranking from high to low as high cloud > altostratus > altocumulus > stratus > stratocumulus > cumulus > nimbostratus > deep convective cloud. Altostratus mainly occurs in northern regions, and high cloud mostly occurs in Tibetan Plateau, southern China mainland and eastern ocean. The vertical distributions of cloud macrophysical characteristics over the six typical study areas have been further demonstrated by constructing PC-tau diagram.