塔克拉玛干沙漠腹地晴天与沙尘暴天气大气边界层对比分析

根据2017、2019年7月塔克拉玛干沙漠腹地GPS探空和地面观测数据，利用位温廓线法等方法，对比分析了沙漠腹地夏季晴天和沙尘暴天气大气边界层结构变化特征。结果表明：晴天和沙尘暴天气大气边界层结构特征显著不同。晴天大气边界层各气象要素垂直分布较为均一，白天对流边界层深厚，高度接近5 km，夜间稳定边界层一般在500 m左右。沙尘暴天气边界层内位温和比湿垂直变化较小，风速较大，可达24.0 m/s，其白天对流边界层在1.5 km左右，夜间稳定边界层在1 km左右。晴天辐射强烈，地表升温迅速，湍流旺盛，是形成晴天深厚对流边界层的主要因素。大尺度天气系统冷平流的动力条件，以及云和沙尘减弱了到达地表的辐射强度是形成沙尘暴天气独特的大气边界层结构的主要因素。

Comparative analysis of atmospheric boundary layer sunny day and sandstorm in the hinterland of Taklimakan Desert

Based on the GPS sounding test data and ground observation data in the hinterland of the Taklimakan Desert in July 2017 and 2019, the characteristics of atmospheric boundary layer structure changes in summer sunny weather and sandstorm weather in the hinterland of the desert were compared and analyzed. The results show that the atmospheric boundary layer structure is significantly different between sunny weather and sandstorm weather, and the vertical distribution of potential temperature, wind speed and specific humidity are quite different. In sunny days, the vertical distribution of meteorological elements in the atmospheric boundary layer is relatively uniform, forming a deep convective boundary layer with a height of up to 5000m, and the stable boundary layer at night is generally about 500m. The vertical distribution of meteorological elements in the boundary layer of sandstorm weather changes greatly. The convective boundary layer is about 1500m during the day, while the stable boundary layer is about 1000m at night. In the land surface process, the net radiation is strong on sunny days, the surface temperature is rapid, and the sensible heat flux energy in the near layer is sufficient, which provides thermal conditions for convective and turbulent motion, and is the main factor for the formation of deep convective boundary layer. However, due to the influence of clouds and dust particles, sandstorm weather blocks the light radiation reaching the surface and weakens the external thermal conditions. At the same time, the cold advection of large-scale weather system provides sufficient dynamic conditions, forcing the temperature of low altitude 2000m to decrease, the wind speed to increase, and carrying a large amount of water vapor, resulting in changes in the vertical distribution characteristics of meteorological elements. Finally, the unique structural characteristics of atmospheric boundary layer in sandstorm weather were formed.