中文摘要：

使用美国NCAR新版MM5V3.6非静力模式，采用两重嵌套方法，模拟了青海湖区域的局地环流及大气边界层特征，并且与无湖试验进行了比较。结果表明：白天由于青海湖的存在有很好的降温作用，夜晚则有保温效应，表现出明显的冷（暖）湖效应；青海湖对感热和潜热的影响有很强的日变化，白天湖面感热、潜热都小，夜间情况相反，这使得白天青海湖是冷干岛，夜间是暖湿岛；青海湖使得白天湖面边界层顶低，陆面边界层顶高，夜间相反。这样的边界层顶高度和温度、地面能量通量相配合，形成了一个很好的保护机制，对青海湖的水土保持和生态环境的维持有正效应；青海湖使得湖面上空大气下沉，陆面上空大气上升，从而产生了湖面上空大气冷干，陆面上空大气暖湿的边界层特征；青海湖边缘的陆面形成的较大的湿气柱围绕着湖面，起到了保护湖面的作用；青海湖低空白天有明显的湖面向四周的辐散气流，而夜间则为从北偏东方向来的陆风。

英文摘要：

A set of double nested numerical simulation tests with and without the Qinghai lakes were conducted by using NCAR nonhydrostatie mesoseale model （MM5V3. 6）. The characteristics of surface temperature, atmospheric boundary layer height, sensible heat flux and latent heat flux were analyzed, and the vertical circulation, land-lake breeze were also simulated. The main results show that （1） The existence of lake shows a strong cold （warm） lake effect to the summer atmospheric boundary layer characteristics over the Qinghai lake region. （2） The impact of Qinghai Lake on sensible heat flux and latent heat flux has significant day change. Both the sensible heat flux and latent heat flux are small in the day, and the situation is contrary at the night. （3） Qinghai Lake makes lake atmospheric boundary layer height lower than the land. （4） The vertical motion is downward over the lake and upward over the land, then the air is dry and cold over the lake, warm and moist over the land. There is the wet air column around lake, which plays a key role in protecting the lake area. （5） 650 hPa wind fields show a clear lake-land breeze.