延安市冬季边界层风、温场特征分布

本文利用1985年12月25日—1986年1月9日的实测资料,分析了延安市冬季边界层风、温场特征。结果表明:延安市冬季低层逆温持续时间长、强度大,逆温持续期近地面几十米表现为混合层结构。边界层风场十分复杂,时空变化大,地面常为小风状态,风向、风速沿垂直方向有明显切变,低层流场有显著渠道效应,山谷风明显。

ANALYSES ON THE CHARACTERISTICS OF WIND,TEMPERATURE FIELDS IN THE BOUNDARY LAYER OF YAN-AN (city) IN WINTER

In this paper, by using the field observational data in the period from December 25, 1985 to January 9 , 1986, the characteristics of wind, temperature fields in the boundary layer of Yan-an in winter are analysed. The results show that, in the lower layer in winter, the sustaining time of temperature inversion is long and its strength is high. During the sustaining period, the atmospheric structure tens meters above the ground manifests itself as mixed layers. The wind field in the boundary layer is very complex and its time-space changes are large. The ground layer is often in a state of light breeze, and both the direction and velocity of wind show an evident shear along vertical direction, while in the lower layer, the flow field has a significant channel effect and the valley wind displays evidently.