关键词: 气溶胶, SAGEⅡ, 沙尘暴

Abstract: SAGEⅡ( stratospheric aerosol and gas experiment Ⅱ) data extending as long as 20 years was used to study both the spatial and temporal distributions and the trend of column aerosol between 5.0 and 15.0 km over East Asia. The transport of aerosol to the upper level and downstream areas by dust activities was also studied. It's found that there are three different kinds of horizontal distributions. In the low level of 5.0 -8.5 km, the high-value area is just above the dust source of aerosol, e.g. Tibetan Plateau, deserts in the northwest of China; in the middle level of 9.0-10.0 km, the high-value area is consistent with the area with high extratropical cyclone frequency; in the high level of 10.5 - 15.0 km, the value in low-latitude is significantly higher than that in high-latitude. Upper level aerosol distributions in all the three levels significantly vary seasonally resulting from different synoptic systems. A downward trend of upper air aerosol is found in recent ten years over East Asia and the aerosol optical depth (AOD) between 5.0 and 15.0 km has decreased by 0.016. It is also found that aerosol between 5. 0 and 11. 5 km has significant positive correlation with the dust storm activity, which infers the injection of surface dust to all the altitude in troposphere. Upper-air-effect-index of dust storm was defined to study the impact of dust storms in East Asia on the downstream areas. The movement of dust towards the east was observed; and the dust could reach the Atlantic Ocean in about 12 days.

Key words: aerosol, SAGEⅡ, dust storm