利用2007?2010年4年间的CALIPSO 5 km二级云数据对中国海及其周边海域层数不同的云的出现概 率(COF)随年度、月份和区域的变化进行了统计分析,并将2007年、2008年的部分统计结 果与MODIS数据的统计结果相比较。结果表明:在研究区域,不同年份层数相同的云的出现概率差别小于3%,且 不同年份的出现概率区域分布相近,在靠近赤道的海域高于80%,在20
N附近海域低于50%,这与MODIS数据 的统计结果相一致;同一年不同月份的出现概率差异明显,但是4年都是在6、7月出现最大值,层数相同的云的 出现概率随纬度变化而明显变化。

The distribution statistics of cloud layers over China Sea and adjacent sea area are derived from 4-year CALIPSO 5 km level 2 version 3 lidar cloud layer data from 2007 to 2010. The changes of cloud occurrence frequencies by year, month and geographic location are analyzed. The statistics of cloud occurrence frequency from 2007 to 2008 MODIS data are used for the comparison. The results show that, in the research area, the differences of cloud occurrence frequencies are less than 3% for clouds with same number of layers in different years, and the regional distributions of cloud occurrence frequencies of different years are similar. Cloud occurrence frequencies are higher than 80% near the equator and less than 50% close to 20
N. The statistical results are consistent with MODIS data. Cloud occurrence frequency has obvious differences for different months within the same year and the maximums of 4 years are all in June or July respectively. The changes of cloud occurrence frequency with latitude are obviously for the clouds with same layer number within the same year.