渤海西岸空气动力学粗糙度特征分析

Analysis of aerodynamic roughness in the western coast of the Bohai Sea

利用2009年12月至2010年11月渤海西岸大港风能塔观测的风速、风向和温度梯度资料,计算风能塔周围空气动力学粗糙度Z0。对比分析了风廓线法和风速标准差法的计算结果,讨论了风速标准差法的适用性以及下垫面空间非均一性对粗糙度的影响。结果表明:风能塔三个主风向上的平均粗糙长度为:0.1319 m(N),0.0386 m(SE)和0.0182 m(SW)。通过严格条件限制,利用风速标准差法可以得到与风廓线法相同的计算效果。同一方位上,利用10—30 m资料计算得到的粗糙度长度的季节差异相对较小,而50—70 m的计算结果差异相对较大。在相同高度上,粗糙度长度计算结果亦存在明显季节差异,反映了随季节变化的植被对地表粗糙度的影响。

Based on the observed wind speed,wind direction and temperature data from wind energy tower at Da-gang in the western coast of the Bohai Sea from December of 2009 to November of 2010,the aerodynamic rough-ness Z0 around the wind energy tower was calculated using two methods：a wind-profile and a wind speed standard deviation.The results were analyzed and compared.The applicability of the wind speed standard deviation method and the effect of the inhomogeneous underlying surface on the roughness were discussed.The results show that the average roughnesses on three main wind directions are 0.1319 m（north）,0.0386 m（south-east）and 0.0182 m （south-west）,respectively.The roughness calculated using the two methods could be similar if a strictly condition control is carried out.On the same direction,the seasonal differences of the roughness calculated by the two meth-ods using 10-30 m meteorological data are not significant,while those using the 50-70 m data are significant.On the same layer,the differences of the roughness between different seasons are significant,which reflects the effect of the seasonal vegetation change on the roughness.