Macroscopic Characteristics Of The Cloud Based On ISCCP Data

Cloud plays an important role in the process of radiation in the Earth's climate system energy budget and water circulation.The change of macroscopic characteristtics of the cloud(cloud amount,cloud height and cloud water content,etc.)may have a significant impact on the global climate,on the contrary,the change of global climate will lead to the adjustment of the cloud features.In this paper, Based on the latest ISCCP(International Satellite Cloud Climatology Project) D2 cloud climate data,we have found the spatial and temporal variations of maco-cloud parameters(cloud amount,cloud top pressure,cloud optical thickness and cloud water path(CWP))over China from 1988 to 2007, then did the correlation analysis and discussed the causes with National Meteorological Information Center released the history of Chinese homogenization temperature, relative humidity and atmospheric pressure in summer.The results show that:(1) Cloud amount,cloud optical thickness and CWP has emerged in the South than in the north of the more obvious zonal distribution.The distribution of Tibetan Plateau is different from the other parts of the same latitude. Cloud optical thickness and CWP is different from Yunnan-Guizhou Plateau in the east and west sides.Cloud top pressure in Southern coastal areas is high,but in Tibetan Plateau is low.(2) In the recent 20 years, cloud amount in the Tibet Plateau showed a decreasing trend,cloud top pressure,cloud optical thickness and CWP are on the rise.; cloud amount of low latitude showed an increasing trend after the first reduction,cloud top pressure increased at first and then has stabilized slightly decreased, cloud optical thickness and CWP changed instability in recent years; cloud amount of high latitude was similar with low latitude,cloud top pressure showed significantly increased firstly and then decreased,cloud optical thickness and CWP showed a rising trend.(3) In the long term trend,cloud amount increased in summer,other seasons showed a decreasing trend; the spatial distribution of the four seasons showed an increasing trend in the east and a decreasing trend in the west.Cloud optical thickness and CWP showed an increasing trend and the rate of increase from spring to winter increased; in the spatial distribution,the rate of increase of CWP in the Tibet Plateau was the maximum in summer which was the most productive convection season. CWP had good correlation with temperature and specific humidity. Cloud top pressure decreased in autumn, other seasons showed an increasing trend, in the spatial distribution,the distribution pattern of four seasons was different,but cloud top pressure in North China which was the high values area increased,North China and The northern Tianshan Mountains in Xinjiang had the most obvious trend in summer. Cloud top pressure reduced and cloud top height rised in the northern Tianshan Mountains in Xinjiang, cloud top pressure had good correlation with temperature and specific humidity. On the contrary, Cloud top pressure rised and cloud top height reduced in North China, cloud top pressure had bad correlation with temperature and specific humidity.