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

摘要： 利用长达20 年的SAGEⅡ(stratospheric aerosol and gas experimentⅡ) 资料, 研究了东亚地区5.0 ～15.0 km 高空气溶胶多年时空分布特征和变化趋势, 并研究了东亚沙尘活动对高空及下游的气溶胶输送。发现东亚高空气溶胶水平分布呈现上中下3 层不同的分布特征, 下层 5. 0 ～8. 5 km 高值区对应气溶胶源区青藏高原和西北沙漠地区;中层 9. 0 ～10. 0 km 高值区对应温带气旋高发的中纬度地区;上层 10. 5 ～15. 0 km 表现为低纬气溶胶含量显著高于高纬地区。高空各层气溶胶的空间分布受天气系统的影响具有明显的季节变化。近10 年来东亚高空气溶胶呈减少趋势, 平均光学厚度约下降了0. 016。另外还发现沙尘活动与 5. 0 ～11. 5 km 范围内的气溶胶显著相关, 反映沙尘活动影响的高度范围可以达到整个对流层。定义沙尘暴高空影响指数, 用来分析东亚沙尘暴对下游地区的影响, 发现随着时间推移沙尘逐渐向东移动, 在约 12 天之后可以到达大西洋。

关键词: 气溶胶, SAGEⅡ, 沙尘暴