资源环境科技发展态势分析平台

Using the Himawari-8 cloud product, this study investigated the seasonal, monthly, diurnal variations as well as spatial and vertical distributions of cloud properties over four typical regions, which are northwest (NW), north (N), southeast (SE) China and Tibetan Plateau (TP). The results show that the cloud occurs most frequently in spring and summer, and the seasonal average cloud top height (CTH) has clear seasonal differences while the cloud top temperature (CTT) is negatively correlated with CTH. A unimodal structure is found for the vertical distribution of occurrence frequency of CTH over SE and TP. By dividing clouds into four types, they show large differences in the probability of occurrence. The study also shows that the monthly cloud fraction (CF) is larger in summer and less in winter except in SE, the monthly CTH changes are relatively small in SE and TP, while the monthly CTT variation is the largest in TP. The total CF increases by 22%, 8%, 3%, and 16% from morning to afternoon in four study areas, respectively. The proportion of four types of cloud families has weak diurnal variation except over TP. In TP, the proportions of high cloud (HC) and low cloud (LC) have a diurnal variation of 30% and 22%, respectively. Note that the relative CF contribution (RCFC) of LC reaches the maximum values in the morning. With the enhancement of convection, the RCFC of DCC and HC increases rapidly. Associated with more active convections, the diurnal variations of CTH and CTT are larger in TP than those in other regions. The clouds in SE have a larger COT and smaller CTH than in other regions, implying more sufficient water supply with low clouds.