The unique terrain and complex atmospheric boundary layer (ABL) processes result in a distinctive spatiotemporal distribution of dust in the Tarim Basin; however, this distribution remains unclear under continuous clear-sky conditions. In this study, 382 cases were selected to investigate the spatiotemporal evolution of dust and its potential mechanisms based on MERRA-2 and ERA5 reanalysis datasets combined with MODIS satellite observations during the warm seasons from 2000 to 2023. Taking the typical case of a completely cloudless on July 24–27, 2016, the dust aerosol optical depth (DAOD) at the margin of the Tarim Basin increased with time. The climatological characteristics showed a high DAOD in the northern, western, and southwestern regions and a relatively low DAOD in the central area. Nocturnal low-level jets dominated by northeasterly winds enhance the low-level westward airflow in weak anticyclonic systems, causing dust accumulation in the west and north of the basin. Vertical mixing within the ABL during the daytime increases dust loading in the residual layer, and these dust particles can ascend to high altitudes after breaking through the ABL by the vertical circulation. The dust loading at the lower level during the daytime was higher than that at night, whereas the opposite was true for the upper level. The downward airflow in the northwest slope of the Tibetan plateau weakens at night, leading to dust being uplifted to higher altitudes and transported outside the Tarim Basin by the westerlies. These results enhance our understanding of dust distribution and related mechanisms in Tarim Basin and support the development and utilization of climatic resources in this region.

中文翻译：

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连续晴空下塔里木盆地沙尘时空演变


独特的地形和复杂的大气边界层 （ABL） 过程导致塔里木盆地沙尘具有独特的时空分布;然而，在连续晴空条件下，这种分布仍然不清楚。本研究基于 MERRA-2 和 ERA5 再分析数据集，结合 2000 年至 2023 年暖季 MODIS 卫星观测，选取 382 例沙尘研究其时空演变及其潜在机制。以 2016 年 7 月 24 日至 27 日完全无云的典型情况为例，塔里木盆地边缘的沙尘气溶胶光学厚度 （DAOD） 随着时间的推移而增加。气候特征显示北部、西部和西南部地区 DAOD 较高，中部地区 DAOD 相对较低。以东北风为主的夜间低层急流增强了弱反气旋系统中的低层西向气流，导致盆地西部和北部的沙尘积累。白天 ABL 内部的垂直混合增加了残余层中的粉尘负荷，这些尘埃颗粒在垂直环流突破 ABL 后可以上升到高空。白天低层的尘埃负荷高于夜间，而高层则相反。青藏高原西北坡的向下气流在夜间减弱，导致沙尘被抬升到更高的高度，并被西风带带到塔里木盆地之外。这些结果增强了我们对塔里木盆地沙尘分布和相关机制的理解，并支持了该地区气候资源的开发和利用。