湖北侧长江三峡河谷地形对风速的影响

选取地处长江三峡河谷(湖北侧)的香溪长江公路大桥桥位区(郭家坝站)附近沿江3个气象站、6个自动站多年的风速、风向资料进行对比分析,讨论了峡谷对河谷内不同区域风速的不同影响。结果表明:在水平方向上,烟墩堡、郭家坝、庙堡等临江3站平均风速偏大、最大风速及极大风速出现大值频次偏高,狭管效应明显,其余非临江站则受局地地形遮蔽影响平均风速偏小、最大风速及极大风速出现大值频率偏低;在垂直方向上,150 m以下风速几乎没有明显的高度变化,实测风廓线指数几乎为0;桥位处阵风性强,阵风系数为1.56。

THE EFFECT OF TERRAIN ON WIND SPEED IN YANGTZE THREE GORGES VALLEY IN HUBEI

We select three meteorological stations and six automatic weather stations which are located along the three gorges valley (in Hubei Province) nearby Xiangxi Yangtze River Highway Bridge (Guojiaba meteorological station). We collected wind speed and wind direction data for comparative analysis, and analyzed the different influence of wind speed in different regions of the valley. The results showed that, in the horizontal direction, the three automatic weather stations of Yandunbao, Guojiaba and Miaobao are near the river, presenting an obvious funnel effect, where average wind speeds are larger, and the frequencies of high-value of maximum wind speed and extreme wind speed increase. The rest of stations located not near the river are affected by the local terrain where average wind speeds are smaller, maximum wind speed and extreme wind speed in large frequency are low; In the vertical direction, the wind speed under 150 meters not change in height, the measured wind-profiling index is approximately zero; At the location of bridge, the value of gust factor is 1.56 where gustiness is strong.