Characteristics of Taklimakan dust emission and distribution: A satellite and reanalysis field perspective
Characteristics of Taklimakan dust emission and distribution: A satellite and reanalysis field perspective
复制标题
塔克拉玛干沙尘排放和分布特征：卫星和再分析现场视角
DOI：
10.1002/2014jd022280
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发表时间：
2014-10-27
影响因子：
4.4
通讯作者：
Liu, H. Y.
中科院分区：
文献类型：
--
作者：
Ge, J. M.;Huang, J. P.;Liu, H. Y.
由于塔克拉玛干沙漠独特的地形和东北风以及特定的天气条件，沙尘颗粒可以垂直上升到10公里。然后，它们可以被西风带水平输送到远下风向的地区。我们结合多角度成像光谱仪（MISR）和正交偏振云气溶胶激光雷达的数据，研究了塔克拉玛干沙漠及其周边地区沙尘的三维分布。春夏季，从塔克拉玛干沙漠向东沿着河西走廊延伸到黄土高原，向南延伸到青藏高原，形成一条气溶胶光学厚度（AOD）较高的沙尘带。春季沙尘气溶胶消光系数从近地面0.340 km− 1迅速下降到5 km处的0.015 km− 1，而夏季沙尘气溶胶消光系数在1.6 ~ 3.5 km之间的变化范围为0.100 ± 0.020，在5 km处下降到0.023 km− 1，表明沙尘气溶胶垂直混合较好。我们进一步使用MISR每日AOD来识别高沙尘日和低沙尘日，然后分析高沙尘日和低沙尘日之间的温度、位势高度和风的复合差异模式。结果表明，尽管春、夏季的天气形势有很大的不同，但两个季节有两个共同的特征：塔克拉玛干地区500 hPa反气旋风异常较强，塔里木盆地850 hPa偏东风增强。这些条件有利于沙尘从干燥的沙漠表面卷吸、垂直飘移和水平输送。
Dust particles from the Taklimakan Desert can be lofted vertically up to 10 km due to the unique topography and northeasterly winds associated with certain synoptic conditions. Then they can be transported horizontally to regions far downwind by westerlies. We combined data from the Multiangle Imaging Spectroradiometer (MISR) and the Cloud‐Aerosol Lidar with Orthogonal Polarization to investigate the three‐dimensional distribution of dust over the Taklimakan Desert and surrounding areas. During spring and summer, a dust belt with high aerosol optical depths (AOD) extends eastward from the Taklimakan Desert to the Loess Plateau along the Hexi Corridor and southward to the Tibetan Plateau. However, the dust extinction coefficients decrease rapidly from 0.340 km−1near surface to 0.015 km−1at 5 km in spring, while the extinction values vary within 0.100 ± 0.020 between the altitudes of 1.6 and 3.5 km and decrease to 0.023 km−1at 5 km in summer, indicating that dust aerosol is relatively well mixed vertically. We further used MISR daily AOD to identify high‐ and low‐dust days and then analyzed composite difference patterns of temperature, geopotential height, and wind between high‐ and low‐dust days. It was found that although the synoptic situations of spring and summer are quite different, there are two common features: a strong anticyclonic wind anomaly over the Taklimakan at 500 hPa and an enhanced easterly wind over the Tarim Basin at 850 hPa for the two seasons. These conditions are favorable for dust entrainment from the dry desert surface, vertical lofting, and horizontal transport.