This study,using the CloudSat and CALIPSO data products from 2007 to 2010,statistically analyzed the horizontal and vertical distribution characteristics of cloud cover and frequency of clouds.Subsequently,the study then compared the results with CloudSat data alone,so as to discuss the spatial distribution characteristic of clouds as observed by CALIPSO.The results show that the global mean total cloud amount is 0.69,with the high values mainly concentrated in the southern hemisphere near the 60°S westerlies,north Pacific storm track and equatorial convergence zone(ITCZ),and low values occurring in the North African desert regions and northern Indian Ocean.The distribution of total cloud amount obtained by the CloudSat/CALIPSO data is basically consistent with that obtained by various cloud observations such as CERES,yet the CloudSat/CALIPSO combination data are able to better respond to the cloud vertical structure,and provide a stronger basis for the global cloud region.Upon comparing the statistical results of the joint observations with the distribution results of clouds using CloudSat data alone,it was determined that high ice clouds over land could be detected more accurately by CALIPSO rather than by radar.In addition,with the decrease in temperature,the advantage of the identification of clouds becomes more apparent.At the same time,CALIPSO is also able to observe some warm clouds with thinner upper cloud optical thickness and no precipitation,as well as small particle size.Ice clouds observed by CALIPSO which have a small particle radius on the top are mainly distributed in the ITCZ,the southern hemisphere near 60°S westerlies and north Pacific storm track belt region.These warm clouds with no precipitation are mainly found in the 10—20 ℃ temperature range of North and South America and South Africa's west coast,while supercooled water clouds are mainly found in the -10—0 ℃ temperature range of the southern hemisphere near the 60°S westerlies.