1991-2010年全球沙尘气溶胶排放量气候特征及其大气环流影响因子

A Simulated Climatology of Dust Aerosol Emissions over 1991-2010 and the Influencing Factors of Atmospheric Circulation over the Major Deserts in the World

利用全球气候模式CAM5.1的20年(1991—2010年)沙尘气溶胶排放量模拟,分析全球沙尘气溶胶排放量的时空变化及其大气环流影响因子。结果表明:20年全球年平均沙尘气溶胶排放总量为1 152±28 Mt,全球沙尘气溶胶排放源主要集中在北非、阿拉伯半岛和中亚、东亚、澳大利亚及北美沙漠地区。北非沙漠地区作为全球最大的沙尘排放源区,占全球沙尘源总量的61.8%。各沙漠区均有显著的沙尘排放的季节变化和年际波动,沙尘气溶胶呈现春、夏季强排放和秋、冬季弱排放的季节循环。相对于沙尘排放的季节变化,其年际变化幅度明显偏弱。基于大气环流指数与沙尘气溶胶排放年际变化的相关显著程度,确定主要影响全球和主要沙漠地区沙尘排放量的大气环流因子:南方涛动指数SOI、北极涛动AO、南极涛动AAO、大西洋年际振荡指数AMO、北太平洋遥相关指数NP以及西太平洋指数WP。全球主要沙漠地区沙尘排放量与大气环流因子之间的相关性具有明显的区域分布特征,在同一沙漠的不同区域甚至可以表现出正负相反的相关性。热带海气相互作用的ENSO循环中,拉尼娜年(厄尔尼诺年)北非地区的沙尘排放量偏多(少),阿拉伯半岛和中亚地区的沙尘排放量偏少(多)。

Based on the 20-year(1991-2010) simulation of dust aerosol emissions with the global climate model CAM5.1,the globally spatial and temporal variations of dust aerosol emissions over major deserts were climatologically characterized,and the atmospheric circulation factors influencing the dust emissions were analyzed.The results indicated that the annual amount of global dust aerosol emission was estimated with 1 152±28 Mt in the 20-year average,the dust aerosol sources were mainly concentrated in five major desert areas in North Africa,Arabian Peninsula and Central Asia,East Asia,Australia and North America.As the world's largest source of dust emissions,North African were accounted for 61.8% of global dust emissions.The emissions over all deserts presented the distinct seasonal and interannual variations.Dust aerosol presented a seasonal cyclewith strong emissions in spring and summer and weak emissions in autumn and winter.Comparedto the seasonal fluctuations of dust emissions,the interannual variability was clearly weaker.Based on the significance levels of correlations between dust emissions and atmospheric circulation indices,the major climate factors influencing global and regional dust emissions over the deserts are determined:SOI(Southern Oscillation Index),AO(Arctic Oscillation),AAO(Antarctic Oscillation),AMO(Atlantic Multidecadal Oscillation),NP(North Pacific pattern)and WP(Western Pacific Index).The patterns of correlations between dust emissions and climate factors had obviously spatial distribution over the desert regions,and even the opposite patterns of correlations exist over a desert region.The La Ni a-and El Ni oyears in the ENSO cycle driven by air-sea exchange are connected with the more and less dust emissions in North Africa as well as the less and more dust emissions in Arabian Peninsula and Central Asia.