Abstract:Based on the verification and evaluation of the quality of CFSR (Climate Forecast System Reanalysis) cloud amount reanalysis data by satellite remote sensing data MODIS, we analyze the average distribution of global total and low, middle, high cloud amount from 1979 to 2009 as well as the cloud amount variation along the latitude. Also, by using empirical mode decomposition (EMD) method, we analyze the change trend of each cloud amount in the recent 30 years. The results show that: (1) the global average total cloud amount in recent 30 years is about 59%, the global total and low, middle, high cloud amounts have obvious zonal distribution characteristics, and there are 3 peak value zones and 3 low value zones for the total cloud amount. (2) The difference of land sea distribution for low cloud amount is obvious and the amount of low cloud over the land is significantly lower than that over the ocean. Except for the two polar regions, the amount of low cloud in the Southern Hemisphere is more than that of the corresponding latitudes in the Northern Hemisphere; the locations of maximum and minimum of high cloud amount are between the mid low latitudes (30°) of Southern, and Northern Hemispheres respectively. In addition, the low value center mainly distributes in the eastern ocean. (3) The variation of total cloud amount is in an increasing trend, and it is specificly displayed as skyrocketed after a slightly decrease with the time. Its jump point year is around 1993, after which total cloud amount increases significantly. Low and high cloud amounts show a decreasing trend, in contrast, middle cloud amount is decreasing. Low cloud amount increases the most by nearly 2% while the change of high cloud amount is smaller.