利用CloudSat卫星资料分析云微物理和光学性质的分布特征

Analysis on Global Distribution Characteristics of Cloud Microphysical and Optical Properties Based on the CloudSat Data

利用2007年1月2010年12月高垂直分辨率CloudSat卫星的2B数据产品,对云微物理特征量(包括云中液态水/冰水含量、液态水/冰水路径、云滴有效半径等)以及云光学参数(云光学厚度等)的全球分布和季节变化进行了统计分析,并研究了云微物理性质对光学性质的影响。结果表明,冰水路径分布在北美南部、南美大陆、非洲大陆、澳大利亚和南亚的陆地上空,以及太平洋、大西洋和印度洋的洋面上空,高值区最大值达600 g·m-2以上;垂直方向上,高值区位于赤道地区8 km附近以及中纬度地区4~8 km高度上。液态水路径在300 g·m-2以上的高值区主要位于太平洋、印度洋和大西洋的中低纬度海域上空,垂直上液态水含量随高度递减。冰云有效半径在高纬度地区近地面层达200μm以上,在赤道附近4~8 km上有1个高值区,南北半球中纬度地区2~4 km上有2个高值区,最大值均达到80μm以上。在1 km以下的边界层水云有效半径值较大,达到12μm以上。总云光学厚度在全球大部分地区【40,高值区普遍位于中高纬度的广阔地区和低纬度靠近大陆的洋面上空;垂直方向上,云光学厚度的高值集中在2 km以下的边界层。云光学厚度的分布受云量、云水含量和云滴有效半径的影响,云量大的地区基本为云光学厚度的大值区。

The global distribution and seasonal variation of the cloud physical characteristics( including the cloud liquid and ice water content,liquid and ice water path,the effective radius,etc.) and cloud optical parameters( the cloud optical depth,etc.) were analyzed by the CloudSat data from January 2007 to December 2010. The results show that: The distribution of ice water path is mainly over the North America,South America,Africa,Australia and the South Asia,as well as the Pacific,Atlantic and Indian Ocean,with the highest values reaching600 g·m- 2or more. In the vertical direction,the high values of ice water content are located near the height of8 km over the equatorial regions and from 4 to 8 km over the middle latitude regions. The high values of liquid water path are located over the Pacific Ocean,the Indian Ocean and the middle and low latitudes of Atlantic. In the vertical direction,the value of liquid water content decreases with height. The ice effective radius reaches its maximum of over 200 μm near the surface at high latitudes,while having a maximum of over 80 μm at 4 ~ 8 km in the equatorial region and at 2 ~ 4 km in the mid-latitude. The liquid effective radius maximizes under 1 km,with a value of over 12 μm. The total cloud optical depth is below 40 around the globe,with largest values located in the vast middle and high latitudes as well as the oceans off the west coasts of low-latitude continents. Large cloud optical depths are concentrated below the boundary layer. The distribution of the cloud optical depth is closely linked to cloud amount,which is in good spatial accordance with the former,and also to cloud water content,and cloud effective radius. The latest analysis of satellite observation data for the climate models,and improvement of the cloud optical parameterizations and cloud microphysical schemes of the models are provided.