关键词: 云量, 云水路径, 云光学厚度, 冰云, 水云, ISCCP D2云资料

Abstract: Based on the monthly cloud dataset of ISCCP D2 from January 1994 to October 2009, the temporal and spatial distribution characteristics of total cloud amount, cloud water path and cloud optical depth over five regions of China were analyzed in detail. The results are as follows: (1) The most liquid-phase cloud distributed over Sichuan Basin to southeast coast of China, while the most ice-phase cloud distributed over northern China and Tibet Plateau. The coverage of cirrus was the widest, and its cloud amount was the biggest over China, followed by cirrostratus, liquid-phase altostratus, liquid-phase cumulus, and the low cloud with ice-phase was the smallest. (2) The total cloud amount, cloud water path and cloud optical depth of stratocumulus, nimbostratus with liquid-phase and deep convective cloud were bigger, which indicated that the cloud water contents were rich, their contributions were bigger to precipitation over Sichuan Basin to southeast coast. (3) The seasonal variations of total cloud amount with different types were obvious over China, and their performances were different over five regions of China. The total cloud amount of most liquid-phase clouds especially nimbostratus was more in summer and less in winter over northern China and Tibet Plateau, while it was less in summer and more in winter over southwestern China and southeastern China. However, the regional difference of cloud amount with ice-phase was little, and the cloud amount of ice-phase altocumulus and altostratus was more in winter and less in summer over most regions, while that of ice-phase cirrostratus and deep convective cloud was more in summer and less in winter, which indicated that the temperature declining and convection weakenning were benificial to gather of ice-phase clouds and development to medium and low layers in winter, while the temperature increasing and convection strengthening were benificial to gather of liquid-phase clouds and development to high layer in summer. (4) The cloud water path of liquid-phase stratus and nimbostratus had obvious seasonal variations over China, and the regional characteristics were obvious, especially the monthly distribution appearred double peaks pattern over southeastern China, the peaks were in February and November. However, the peak of cloud water path of ice-phase clouds occurred in summer over northern China and winter in southern China.

Key words: cloud amount, cloud water path, cloud optical depth, ice-phase cloud, liquid-phase cloud, ISCCP D2 cloud data