不同下垫面下风电场对夏季气候的影响

The Impact of Wind Farm on Local Climate under Different Underlying Surface Conditions during Summertime

随着风力发电的快速发展,集中式风电场建设运行对气候环境产生的影响受到了广泛的关注。为了研究局地气候对不同下垫面条件下风电场运行的响应特征,以青海湖西南部的乌兰茶卡至共和沙珠玉乡为中心,使用中尺度气象数值模式WRF(Weather Research and Forecasting Model)及Fitch风机模型分别在平坦峡谷、高海拔山地和水体下垫面条件下,开展风电场运行的气候效应敏感性数值试验,结果表明:在同等装机的理想情景下,3种下垫面风电场内近地层平均风速均呈现减弱特征,且夜间风速衰减的幅度及范围强于白天,垂直方向上的风速衰减可达600 m;平坦峡谷和水体下垫面风电场内2 m气温以降低为主,可能与该区域负的温度梯度及水体表面蒸发增强有关,且夜间降温更显著,而高海拔地区的气温变化较弱;风电场内2 m湿度变化不明显,总体以弱降低为主,其中水体风电场内夜间湿度减小更明显;同时,风机扰动运行使得边界层高度显著增加。可见,不同下垫面条件下风电场运行的气候响应特征不同,这主要与不同下垫面条件下的差异化气候背景有关,也受风机空间排布特征的影响。研究成果可为气候友好型风电场布局规划提供一定支撑。

With the rapid development of wind power generation,the impact of the construction and operation of utility-scale wind farms on the local climate has attracted extensive attention.In order to study the characteristics of the local climatic response to the deployment of wind farms under different surface conditions,the area from Wulan Chaka to Gonghe Shazhu Yuxiang,which is located in the southwest of Qinghai Lake,was chosen as center,and the mesoscale meteorological numerical model WRF(Weather Research and Forecasting Model)and the Fitch wind turbine model were carried out under the conditions of flat canyons,high-altitude mountains and water body,respectively.The results showed that:Under the ideal situation of the same installed capacity,the averaged wind speed inside the wind farms showed the significant decrease trends under the three sensitivity experiments,and the amplitude and scope of wind speed attenuation was stronger during nighttime than that during the daytime,and the wind speed attenuation in the vertical direction can reached up to 600 m.The 2 m temperature inside the wind farms located in flat canyons or water body mainly decreased,which was possibly related to the negative temperature gradient and the water evaporation enhancement,and the temperature cooling was more significant during nighttime while no significant changes in 2 m temperature were detected over the mountain wind farm.Meanwhile,the changes of 2 m humidity inside the wind farms were not obvious,and the overall decreased trends were mainly weak during nighttime.Due to rotation of the wind turbine,the planetary boundary layer height increased significantly.The characteristics of the local climatic response to the deployment of wind farms under different surface conditions were different,which was mainly related to the different climatic features under different surface conditions,and was also affected by the spatial layout of wind turbines.These results can provide some support for the design of climate-friendly wind farms.