塔里木盆地中的大气环流及昆仑山北坡的黄土堆积

通过分析塔克拉玛干沙漠风积地貌形态所揭示的风向及盆地边缘25个气象站40 a的盛行风，我们恢复了盆地中沙尘暴形成时的风场。对大气环流分析表明，在暖季（春、夏）由于地面对大气感热加热作用强烈，形成了浅薄的热低压。当冷空气入侵时，在和田—于田—民丰一带形成强大的辐合上升区，使这个地区成为中国沙尘暴发生频率最高的地区，其扬起的粉尘沉降在昆仑山北坡而形成黄土堆积。由于冷空气入侵的强度不同，粉尘的扬升高度也不同，昆仑山北坡黄土厚度表明平均扬升高度在海拔2 900~3 400 m左右，最强的沙尘暴可将粉尘扬升到5 500 m的西风急流区。

Atmospheric Circulation in Tarim Basin and Loess Accumulation in Northern Slope of Kunlun Mountains

Having analyzed the prevailing wind directions that are showed by Taklimakan Desert dunes shapes and that have been observed by 25 weather stations for 40 years around the Taklimakan Desert,we reestablished the wind field map when duststorm occurred in the Tarim basin.The analysis on the atmospheric circulation reveals that the flimsy thermal low was formed in the warm seasons(spring & summer) as the surface heat being transferred to air through the sensible heat.When the cold airflow invaded into the basin,powerful current convergence zones of uplift formed along the belt of Hetian-Yutian-Minfeng in south basin,where became the highest frequently duststorm-occurring area in China.The uplifting sand-dust were transported and deposited on the northern slope of Kunlun Mountains,forming loess deposition.The uplifted altitudes of sand-dust vary with the intensity of cold airflow intruding.On northern slope of Kunlun Mountains the average altitude is at 2 900~3 400 m indicated by the distribution of loess deposition.The strongest duststorm can raise sand-dust up to 5 500 m height and come into the westerly jet region.