基于CALIPSO资料的东亚地区气溶胶垂直分布特征分析

目的分析东亚地区气溶胶的垂直分布特征。方法利用2006—2012年CALIPSO星载激光雷达资料,基于气溶胶光学厚度分析结果,选取有代表性的经度带和纬度带,分别研究东亚大陆东部沿海地区气溶胶的垂直分布和东亚-北太平洋地区沙尘气溶胶的垂直分布。在此基础上,选取三个有代表性的格点,进一步研究华北和华南地区气溶胶的垂直分布及塔克拉玛干沙漠沙尘的气溶胶垂直分布,并对其垂直分布特征曲线进行拟合。结果平均来看,除少数地区个别月份外,东亚地区气溶胶主要出现在近地面附近。东部沿海地区,一定高度以上,气溶胶的消光系数随高度的增加总体上呈指数减小;西北沙尘源区,大致在近地面至对流层中层,沙尘气溶胶的消光系数随高度的增加几乎呈线性递减。气溶胶的垂直分布具有显著的月际变化和地区差异,中纬度地区,亚洲沙尘气溶胶跨北太平洋传输在1—5月份较强。结论高垂直分辨率的CALIPSO资料可作为精细分析气溶胶垂直分布特征的有力工具。

Vertical Distribution Characteristics of Aerosol over East Asia Based on CALIPSO Data

Objective To analyze the vertical distribution characteristics of aerosols over East Asia. Methods Based on the CALIPSO spaceborne laser radar data from 2006 to 2012 and the analysis result of the aerosol optical depth, the representative longitude and latitude bands were selected to study the vertical distribution of aerosols in the eastern coastal areas of East Asia and the vertical distribution of dust aerosols in East Asia-North Pacific region. Ulteriorly, three representative grid points were selected to study the vertical distribution of aerosols in North China and South China, and the vertical distribution of dust aerosols in the Taklimakan Desert. At last, the vertical distribution fitting curves were carried out. Results On the average, the aerosols over East Asia mainly appeared near the ground except for a few areas in a few months. The aerosol extinction coefficient generally decreased exponentially with height above the certain height in the eastern coastal areas of China. The dust extinction coefficient of the dust aerosol decreased almost linearly with height in the dust source area roughly from the ground to the middle layer of the troposphere. The vertical distribution of aerosol had apparent inter-monthly variation and regional difference. In the mid-latitude area, the transmission of Asian dust aerosols between the North Pacific was stronger in January to May. Conclusion CALIPSO data of high vertical resolution can be used as a powerful tool for fine analysis of aerosol vertical distribution.