Abstract:Based on the surface observation data from the representative station over eastern Hexi Corridor, the NCEP 2.5°×2.5° monthly average upper air sounding data from surface to 300 hPa during 1971-2016, and the daily upper air densely observed data every 10 m at 07:00 BT and 19:00 BT from 2006 to 2016 in Minqin, the inter annual variation characteristics of winter sandstorm over eastern Hexi Corridor in recent 45 years are analyzed. At the same time, the synoptic causes, physical quantity field and near surface boundary layer characteristics of the two sandstorm processes in November 2016 are also analyzed. The results show that the number of winter sandstorms over eastern Hexi Corridor has decreased in recent 45 years. The main causes of strong wind and dust weather are not only related to the intensity of large scale cold and warm airs and circulation situation, but also closely related to cold front transit time, diurnal variation, wind speed and humidity near the surface. Near surface, the temperature inversion layer is thick and strong from night to morning, atmospheric stratification is stable, which weakens the strength of sandstorms, but surface inversion from afternoon to evening is thin and weak, strengthening the atmospheric instability, momentum down propagation and wind speed, thus further enhancing the strenght of sandstorms. The drier the surface layer, the faster the wind speed, and the stronger the sandstorm.