塔里木盆地夏季沙尘气溶胶持续“滞空”变化特征及与青藏高原大地形作用的关联

Affected by the thermal effect of Taklimakan Desert in summer and the topography effect of deep basins composed of Tibetan Plateau (TP) and surrounding mountain groups, the unique regional floating dust weather phenomenon with dust aerosols persistently suspending occurs frequently in summer over the Tarim Basin (TB), exhibiting the weekly-monthly temporal scale in the basin scope. However, the spatiotemporal variations of dust aerosols suspending in summer over the TB and the association with the thermal effect of the TP’s large topography are still lacking of systematic research. The project will utilize the multi-source information integration with long term data of satellite remote sensing products, meteorological observation, atmospheric environmental monitoring, combining with the approaches of atmospheric climatic and dynamics diagnosis and numerical modeling, to comprehensively characterize deep atmospheric boundary layer during summer dust aerosols suspending and vertical variation of optical properties of dust aerosols over the TB, to explore the synergistic effect of the desert thermal force and the topography of the special deep basin on dust aerosols persistently suspending in summer over the TB, to reveal the mechanism of dynamic and thermal forcing over the TP on dust aerosols suspending, which aims to comprehensively understand the TB and the large topography forcing effect of the TP on during environment and climate change in the TB and other arid region in Central Asia.

受塔克拉玛干沙漠夏季热力作用与青藏高原及其周边山群构成的深盆地地形效应的共同影响, 塔里木盆地夏季常见沙尘气溶胶持续“滞空”的独特浮尘天气现象，且具有周-月时间尺度大范围浮尘“滞空”的气候特征。然而，塔里木盆地夏季“滞空”浮尘的时空变化特征及与青藏高原大地形夏季热力效应的关联目前尚缺少系统研究。本项目拟利用多年卫星遥感、地基探测的气象-环境监测等多源资料，通过天气气候诊断、大气动力学分析与数值模拟相结合的技术途径，综合分析塔里木盆地及其周边区域夏季沙尘气溶胶时空变化特征，系统认识塔里木盆地夏季“滞空”浮尘天气的“超高”大气边界层结构和沙尘气溶胶光学特性垂直变化特征；探索沙漠热力强迫与特殊深盆地地形对塔里木盆地夏季大气沙尘气溶胶持续“滞空”的协同作用，揭示青藏高原动力、热力强迫对沙尘气溶胶 “滞空”变化的影响机理。意在加深理解塔里木盆地及其中亚干旱地区环境气候变化中青藏高原大地形强迫效应。

受塔克拉玛干沙漠热力作用与青藏高原及其周边山群构成的深盆地地形效应的共同影响, 塔里木盆地春夏季常见沙尘气溶胶持续滞空的独特浮尘天气现象，且具有周-月时间尺度大范围浮尘滞空的气候特征。然而，塔里木盆地滞空浮尘的时空变化特征及与青藏高原大地形热力效应的关联目前尚缺少系统研究。本项目利用近30年地基探测的气象-环境监测、再分析数据等多源资料，通过天气气候诊断、大气动力学分析与数值模拟相结合的技术途径，综合分析塔里木盆地浮尘天气及持续浮尘滞空的气候特征，系统认识塔里木盆地滞空浮尘天气的“超高”大气边界层结构和沙尘气溶胶光学特性变化特征，揭示青藏高原动力、热力强迫对沙尘气溶胶滞空变化的影响机理。结果表明，（1）近30年，塔里木盆地浮尘日数年际变化趋势呈“V”型特征，盆地内呈现明显的空间差异，盆地南部皮山—和田—策勒—民丰一线地区维持一个浮尘天气频发区的极值中心。持续2天及其以上的浮尘天气占浮尘日总数的64.25%；（2）夏季，盆地晴日对流边界层高度接近3600 m，浮尘日达2700 m，白天，浮尘气溶胶减少了地表短波辐射和感热加热，降低了对流边界层高度；夜间，浮尘向下长波辐射削弱了地表辐射冷却，抬升稳定边界层高度；（3）近30年，青藏高原春季冷源异常增加，导致塔里木盆地东北部地表温度异常升高、湿度异常降低，PBLH异常降低，利于地表起沙、悬浮；盆地西南部相反，浮尘天气异常减少；（4）青藏高原海拔高度的降低会导致PBLH,CAPE和10米风速的增加，其中前两者有利于沙尘气溶胶向上的扩散，后者会增强沙尘的排放，但不利于垂直方向上扩散，有助于浮尘天气的维持。以上结果加深理解了塔里木盆地及其中亚干旱地区环境气候变化中青藏高原大地形强迫效应。