塔克拉玛干沙漠与撒哈拉沙漠沙尘气溶胶光学特性对比研究

Comparative Study on Optical Characteristics of Dust Aerosols in the Taklimakan Desert and the Sahara Desert

基于2007—2021年CALIPSO和MODIS主、被动卫星遥感探测数据,对塔克拉玛干沙漠和撒哈拉沙漠的气溶胶光学特性时空分布特征进行探究及对比分析。结果表明:(1)两大沙漠的沙尘气溶胶对总气溶胶的贡献率最大,气溶胶类型季节变化的相对单一性反映了塔克拉玛干沙漠和撒哈拉沙漠地区存在沙漠沙尘排放对总气溶胶成分的显著影响;(2)塔克拉玛干沙漠气溶胶光学厚度AOD的峰值出现在春季(春季>夏季>秋季>冬季),而撒哈拉沙漠AOD的峰值出现在夏季(夏季>春季>秋季>冬季);(3)撒哈拉沙漠总气溶胶抬升高度与塔克拉玛干沙漠相近,但近地面层消光系数明显小于塔克拉玛干沙漠;塔克拉玛干沙漠的消光系数平均值在所有季节中均大于撒哈拉沙漠,故塔克拉玛干沙漠的沙尘气溶胶AOD比撒哈拉沙漠的大;相比沙漠沙尘气溶胶,塔克拉玛干沙漠和撒哈拉沙漠都无明显的污染沙尘和抬升烟活动。上述研究结果揭示了两大沙漠源区沙尘气溶胶光学特性的观测事实与利用大气气溶胶时空变化特征反映区域气候变化的可能性。

Based on CALIPSO and MODIS active and passive satellite remote sensing data from 2007 to 2021,this study explores and compares the spatiotemporal distribution characteristics of aerosols in the Taklimakan Desert(TD)and the Sahara Desert(SD).The results show that:(1)The contribution rate of desert dust aerosols to total aerosols in the two major deserts is the highest,and the relative singularity of aerosol type seasonal changes reflects the significant impact of desert dust emissions on total aerosol composition in the TD and SD;(2)The peak of AOD in the TD occurs in spring(spring>summer>autumn>winter),while the peak of AOD in the SD occurs in summer(summer>spring>autumn>winter);(3)The total aerosol elevation in the SD is similar to that in the TD,but the extinction coefficient(EC)in the near surface layer is significantly lower than that in the TD;The average extinction coefficient of the TD is greater than that of the SD in all seasons,so the AOD of sand and dust aerosols in the TD is greater than that in the SD;Compared to desert dust aerosols,neither the TD nor the SD show significant pollution,dust,and smoke activity.The above research results reveal the observational facts of the optical characteristics of dust aerosols in the two major desert source areas and the possibility of using the spatiotemporal variation characteristics of atmospheric aerosols to reflect regional climate change.