Analysis On Distribution Characteristics Of Cloud Microphysical And Optical Properties Based On The Cloudsat Data

The global and Asian distribution of the cloud physical characteristics (including thecloud liquid and ice water content, liquid and ice water path, the effective radius, the numberconcentrations etc.) and cloud optical parameters(the cloud optical depth, etc.) are analyzedbased on the CloudSat data from Jan.2007to Dec.2010.Results show that the ice water path distributes mainly over the North America, SouthAmerica, Africa, Australia and the South Asia, as well as the Pacific, Atlantic and IndianOcean. In the vertical direction, the high values of ice water content are located near the heightof8km over the equatorial regions and from4to8km over the middle latitude regions. Thehigh values of liquid water path are located over the Pacific Ocean, the Indian Ocean and themid and low latitudes of Atlantic. In the vertical direction, the value of liquid water contentdecreases with height. The total cloud optical depth is below40around the globe, with largestvalues located in the vast middle and high latitudes as well as the oceans off the west coasts oflow-latitude continents. Large cloud optical depths are concentrated below the boundary layer.The higher values of ice water path in Asia locate in the south of40degrees north latitude.It maximizes in the south area in summer and minimizes in the northwest area in winter. Theliquid water path has a maximum over the Tibet Plateau in summer, and over the east ocean inwinter. The ice water content maximizes near the height of8km, which has higher values overthe south area, the east ocean, and the Tibet Plateau. In addition to the Tibet Plateau andnorthwest area, the liquid water content has its maximum below the boundary layer. The totaloptical depth maximizes over the Sichuan basin throughout the year, of which most areas reachtheir highest values in winter besides the Tibet Plateau.The arid area is under the control of sinking airflow, which is not conducive to producingclouds and precipitations. The value of ice/liquid water path over the arid area is far lower thanthe humid area. In the vertical direction, the difference of the value of ice water content islargest between the humid area and arid area. Large liquid water contents are concentratedbelow the boundary layer. The highest value reaches over the humid area in summer, and overthe arid area in spring.The climate model cannot simulate the cloud physical properties precisely. The simulation of the ice water content over the mid-high lattitudes approaches the observations,but larger deviations in the equatorial regions and North Polar Regions. The modelunderestimates the liquid water content below boundary layer largely while comparing withthe satellite data.This paper takes advantages of the high vertical resolution of the CloudSat data, andprovides the climate distributions and seasonal varitions of the cloud physical properties,which improves the cloud optical parameterizations and cloud microphysical schemes of theclimate models.