A Study of the Vertical Structure and Distribution of Cloud System in China from Upper-Air Observations

The study of the vertical structure and distribution of clouds is very important, while there are few direct and valid observation methods in the meteorological operation. Water vapor in the air condenses as a cloud particle when it is saturated or super-saturated. However, the relative humidity is uncertain between saturation with respect to water and ice, which can happen in ice cloud or mixing cloud. A method of achieving cloud structure from sounding data is used. In this method, humidity threshold is set and humidity jump is identified from the sounding data, in order to obtain cloud base, cloud top and interlayer of clouds. Data used here are L-band sounding data (second data) of the 91 Chinese meteorological operation stations during 2008 and 2009. The cloud vertical structure gained above is then validated with CloudSat data of the corresponding time and region. As approved reasonable above, this method is then utilized with Chinese satellite in geosynchronous orbit (FY2) data, for the purpose of obtaining spatial and temporal variation of cloud vertical structures, following typical weather system in China. A statistical analysis of cloud vertical structures is also provided for different seasons, areas and weather systems. The results here will hopefully facilitate the studies on cloud-radiation reaction, cloud precipitation efficiency, potential of artificial rainfall enhancement and so on.