一种基于粗糙度分布的大风风速降尺度方法初步研究——以上海市域为例

摘要

The refined and accurate prediction for speed of gale has important significance to wind power forecast and wind disaster defense.For Shanghai region,the distribution of aerodynamic roughness is estimated on the basis of morphology method,and the refined wind speed at 10 m is reckoned by the interpolation method of wind speed stratification at surface layer.A gale process from 20∶00 January 23 to 20∶00 on 24,2016 is selected for the evaluation of the method through the comparisons of spatial distribution,temporal variation and vertical wind profile characteristics among wind speed from downscaling simulation,surface observation and ECMWF forecast.Results show that this downscaling nethod is able to simulate the spatial distribution of surface wind speed with more details in Shanghai area.As a whole,the simulation accuracy is high in the central urban area while low in the suburbs.However,it has obvious improvement comparing with the counterpart of ECMWF amd can be used to provide technical support for fine prediction of wind speed.%精细准确预报大风风速对于风功率预报和风灾防御具有重要意义.本文以上海市域为研究区域,基于形态学方法估算上海市域空气动力学粗糙度分布,并通过近地层分层风速插值方法推算上海市域10m高度精细风速分布.针对2016年1月23日20时-24日20时一次大风过程开展实证检验,对比分析降尺度模拟风速、地面实测风速、ECMWF预报10 m风速的空间分布、时间变化以及垂直廓线特征.结果表明,该方法可以较好地模拟上海市域风速大小的精细空间分布,模拟精度总体上表现为中心城区精度高、郊区精度稍低,但相比于ECMWF预报10 m风速分布有了明显提高,可以为风速的精细化预报提供技术支撑.