塔里木盆地南缘持续性浮尘天气的维持机理研究

The persistent floating dust events in the southern margin of the Tarim Basin have leaded much dust aerosol suspending in the atmosphere for a long time, and produced great influences on the regional weather, climate and human settlements. In order to scientifically understand the laws of the emergence and vanishing of persistent floating dust events, and further research the influences on the regional changes of dust aerosol, the sustaining mechanisms of persistent floating dust events are needed to be revealed. The project takes hotan oasis in the southern margin of the Tarim Basin as core study area, to develop comprehensive field experiment on vertical structures of dust aerosol and boundary layer during persistent floating dust events by means of meteorological gradient tower, LIDAR, wind profile radar, sounding and unmanned aerial vehicle. Based on the technological approaches including multi-variant data analysis, theoretical analysis of atmospheric dynamics and numerical simulation, to study the vertical structures and its evolution rules of dust aerosol and boundary layer during persistent floating dust events, and dissect the correlations between topography of the Tibetan and atmospheric flow fields, boundary layer structures, and confirm the dynamic and thermodynamic factors influencing the changes of dust aerosol, and quantificationally assess the contributions on the maintenance of persistent floating dust events of topography of the Tibetan, atmospheric flow fields and boundary layer structures. The above works are meant to systematically illuminate the sustaining mechanisms of persistent floating dust events in the southern margin of the Tarim Basin.

塔里木盆地南缘的持续性浮尘天气导致了沙尘气溶胶长期滞空的独特区域现象，影响着区域天气气候和人居环境。揭示沙尘气溶胶持续滞空的维持机理，是科学认识这一独特现象生消规律和深入研究沙尘气溶胶影响区域变化的基础。项目拟选择盆地南缘的和田绿洲为研究核心区，借助气象梯度塔、激光雷达、风廓线雷达、常规探空和无人机等观测手段，开展持续性浮尘天气过程的沙尘气溶胶和边界层气象要素垂直结构外场观测试验，结合再分析资料，开展多源数据综合分析，通过大气动力学理论分析与数值模拟试验相结合的技术途经，研究持续性浮尘天气过程沙尘气溶胶和边界层的垂直结构及其演变规律；剖析青藏高原大地形对大气流场与边界层结构的关联作用；确定影响持续性浮尘天气过程沙尘气溶胶变化的动力、热力因子；定量评估青藏高原大地形、大气流场及边界层结构对持续性浮尘天气维持的贡献，意在系统地阐明塔里木盆地南缘持续性浮尘天气维持的机理。

塔里木盆地南缘的持续性浮尘天气导致了沙尘气溶胶长期滞空的独特区域现象，影响着区域天气气候和人居环境。通过开展边界层综合观测试验，结合数值模拟和多源数据分析，厘清了浮尘天气大气边界层沙尘气溶胶演变规律，剖析了青藏高原大地形、大气流场和边界层结构对浮尘天气维持的影响作用。结果表明，研究区76.0%左右的浮尘天气维持时长小于5d；浮尘天气近地表沙尘气溶胶粒径集中在0.45-0.70μm；0:00-10:30和21:00-22:00沙尘通量为负值，沙尘粒子沉降过程更为显著；浮尘天气边界层内沙尘气溶胶集中分布于3.0km以下，显著高于沙尘暴天气；日均边界层高度符合晴天（1812.8m）＞浮尘（1711.5m）＞沙尘暴（1532.5m）的分布规律，各天气转换过程中边界层结构也存在显著变化。大气流场中的10m风速和边界层结构中的大气稳定度受青藏高原地形变化影响最大，进而影响着浮尘天气的沙尘浓度和持续时长。相关研究结果和观测数据有助于提升对浮尘这一极端沙尘天气的科学认识，又可为地方浮尘天气的预报预测与应对提供支撑。