YSU边界层参数化方案中不同地形订正方法对地面风速及温度模拟的影响  

Effects of different topographic correction methods on the simulation of surface wind speed and temperature in parameterization scheme of the YSU boundary layer

作　　者：郑亦佳[1] 刘树华[1] 缪育聪[1] 王姝[1] 

机构地区：[1]北京大学物理学院大气与海洋科学系,北京100871

出　　处：《地球物理学报》2016年第3期803-815,共13页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41175004);国家公益性行业(气象)科研专项(GYHY201106033)共同资助

摘　　要：为了修正中尺度气象模式WRF(Weather Research and Forecasting model)对低层风速模拟的系统性误差,有学者在新版本WRF模式的YSU(Yonsei University)边界层参数化方案中加入了两个地形订正方法:Jiménez方法和UW(University of Washington method)方法.本文利用这两个地形订正方法,选取了两个时间段,对北京地区的地面气象要素以及气象要素垂直廓线进行了个例模拟研究,模拟结果和观测数据的比对表明在北京地区:是否采用地形订正,对地面温度的模拟几乎没有影响;采用地形订正后,模式对地面风速的模拟有明显的改进,两种方法对风速模拟的差别主要体现在山/丘陵地区;Jiménez方法在山/丘陵地区的模拟风速明显偏大,而采用UW方法进行订正后,模拟的风速减小,更接近观测值;两种方法在山谷地区对风速均有一定的过度订正.通过分析气象要素的垂直廓线发现,不同地形订正方法主要影响的是2000m以下的低层风速.总体而言,UW地形订正方法在北京地区更为适用,采用UW方法后,模拟得到的地面气象要素的各项统计参数基本达到了统计基准值.In previous work,two methods of topographic correction have been added into the parameterization scheme for the Yonsei University（YSU）boundary layer of the Weather Research and Forecasting（WRF）model,which aims to reduce the errors of the model caused in simulation of low-layer wind speed.Using a case study,this work attempted to analyze the applicability of these two different methods in the simulation of meteorological factors over Beijing during two periods.The performance of WRF was evaluated against observation data with statistics.The results show that the impact,whether terrain correction is done or not,on the surface temperature simulation is little.The surface wind speed simulated by two methods is improved obviously,and the difference is mainly manifested by the surface wind at hills andmountaintops.The UW（University of Washington）method can simulate wind speed better than the Jiménez method,which is more approximate to observation data.However,wind speed in valleys is over corrected by both UW and Jiménez methods.Analysis of the vertical profile of meteorological factors indicates that different methods mainly affect the low-layer wind speed simulation under 2000 m.On the whole,the UW method is a more appropriate choice,since the statistical parameters of surface meteorological factors simulated by the UW method can largely meet the statistical benchmarks.

关 键 词：地形订正 风速 地面气象要素 WRF模式 边界层方案 

分 类 号：P421[天文地球—大气科学及气象学]