淮河流域风场垂直结构特征分析

Analysis of the Vertical Structure of Wind Fields in Huaihe River Valley

为进一步加深南北气候过渡带上山地丘陵地区的风场认识,利用淮南2015年3月至2016年2月ST(Stratosphere-Troposphere)风廓线雷达的探测资料,分析了该地区20km高度内风场的变化特征及垂直结构。结果表明:淮河流域850hPa、700hPa、500hPa、100hPa等压面高度上,风场有明显的垂直变化,风速及其波动幅度随春、夏、秋、冬先减小后增大,且随高度增加,夏季最小、冬季最大的季节规律逐渐增强;风场的垂直分布存在差异,在中低层以下,以小于10m/s的风为主,风向转换多,中低层以上10~25m/s的偏西风居多;年平均风场结构为低层以5m/s北风为主,到2km左右向西偏转,风速小于10m/s,在5km高度处形成15m/s的西风,且风速持续增大,10km左右达到25m/s后逐渐减小,到15km左右风向顺时针向北偏转,直到20km附近与低空风场相近。

To further understand wind fields in mountains and hilly areas in the north-south climate transition zone, based on the March 2015 to February 2016 observational data of ST (stratosphere-troposphere) wind profiler radar, the variation characteristics, and vertical structure of 20-km high wind fields in Huainan were analyzed. The results show the following: In Huaihe River valley, the wind field exhibited significant vertical changes at 850 hPa, 700 hPa, 500 hPa, and 100 hPa;through the seasons, the wind speed and its amplitude first decreased and then increased;they were minimum in summer, followed by in autumn, and maximum in winter, whereby the seasonal variation amplified with increasing height. The vertical distribution of the wind field displayed a great difference;the speed was mainly less than 10 m/s, and the wind directions below the middle and lower levels shifted;western winds of 10-25 m/s dominated the region above these levels. As observed from the annual wind vertical structure, in the lower level, mainly about 5 m/s southern wind turned to the west with less than 10 m/s at 2 km height;15 m/s western wind was developed at 5 km height;its speed continued to increase and reached 25 m/s at 10 km height;when turning north from 15 km height , it gradually decreases to a level closer to that of the lower wind field until about 20 km.