三峡坝区的地面风场与大气扩散气候特征

利用三峡坝区4个气象站和宜昌站的地面观测资料，统计了各站多年、逐年、分季平均风速和风向频率，揭示了地面风场若干气候特征，提出了坝区典型风场模型；并通过分析各站多年、分季联合频率，对坝区大气扩散的气候特点与能力做了初步评价。

An Analysis of Features of Surface Wind andAir Diffusion in Three Gorges Dam Area

The features of surface wind and air diffusion in the Three Gorges dam area is analysed according to the climatic viewpoint. The main results include that the average wind speed in the dam area is slightly greater than that in Yichang station, but Zigui station less distinctly; the wind normal speed is greater in winter and spring, and least in autumn; the calm in morning often appears in autumn and winter; the monsoon feature is not marked, but the wind daily variation distinct, that is to say, it is typical mountain and valley breeze. According to these features, the typical wind field charts in the day and night are given. By wind frequency analysis jointed air stability, it is found that the air diffusion direction pointed to the Changjiang River valley, therefore, the air pollution round this place will be aggravating. As a whole, the air diffusivity is lower in the dam area in autumn and winter.