Impact of Eurasian Atmospheric Circulation on Dust Events in Spring over Northern China

Based on meteorological observation data from701 meteorological stations in China during 19602010,two dust indices,which are Taklimakan Dust Index(TDI)and Gobi Dust Index(GDI),were used to characterize the statistical feature of the dust event occurrence.In general,TDI and GDI both exhibit a sudden decrease in the mid 1980s.Although the intensity of GDI were smaller than the TDI's since 1960's,its inter-annual variability was larger.We also analyzed the differences of atmospheric circulation between years with high and low dust index values.The results indicated that the low dust index values in Southern Xinjiang was likely caused by the waken Mongolia Cyclone and the thermal low pressure in the Taklimakan region,but that the intensity of Siberia Cold High Pressure and the Mongolia High Pressure became waken was the main mechanism of low dust index values in the Inner Mongolia.