一次向西输送的亚洲沙尘过程

Analysis of an Asian Dust Moving in West Direction

一般情况下发生在中国和蒙古国的沙尘天气是向东移动的。对2004年11月24～27日新疆北部的NOAA—AVHRR遥感数据进行沙尘提取发现，在新疆北部的古尔班通古特沙漠发生了明显的沙尘现象，沙尘却向西移动，经过阿拉山口向哈萨克斯坦输送。使用地面台站的观测数据对此进行了验证，发现地面确实观测到了沙尘现象，而且在850hPa的高空存在明显的偏东大风，这说明近地面的东风将沙尘向西输送，导致沙漠西面的台站观测到沙尘现象。

Generally, it is believed that Asia dust is always transported in east direction. However, based on dust detection of NOAA16-AVHRR data on 24-25, Nov. 2004, this paper found that there happened an obvious dust weather in the Gurbantonggut desert located in northern part of Xinjiang province, and it moved in west direction across Ala mountain pass to the Republic of Kazakhstan. It is further validated by using weather observation of meteorological stations. In addition, there existed an obvious east wind at 850 hPa altitude with a wind speed of over 14 m· s^-1 in several stations. It means that the east wind carried dust and moved in a west direction, which resulted in the emergence of dust weather on the west side of the desert.