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