WRF模拟青藏高原东南部极端旱涝年降水的参数敏感性研究  

Parameters Sensitivity Analysis on Simulation of Rainfall in Drought-Flood Year on Qinghai-Tibetan Plateau by WRF Model

作　　者：吴遥[1,2] 李跃清[2] 蒋兴文[2] 董元昌[2] 

机构地区：[1]成都信息工程大学大气科学学院/高原天气与环境四川省重点实验室,成都610225 [2]中国气象局成都高原气象研究所/高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072

出　　处：《高原气象》2017年第3期619-631,共13页Plateau Meteorology

基　　金：公益性行业(气象)科研专项(GYHY201406001);国家自然科学基金项目(91337107;41275051);中国气象局成都高原气象研究所基本科研业务项目(BROP201514);四川省应用基础研究计划重点项目(2016JY0046)

摘　　要：为了进一步评估和提高区域模式对青藏高原地区极端气候的模拟能力,利用WRF模式,采用不同模式参数(包括边界位置、积云对流、边界层参数化方案和水平分辨率)模拟了青藏高原东南部极端旱(2006年)、涝(1998年)年夏季降水。对比不同参数模拟的降水结果表明:整体而言,无论是旱年还是涝年,除南边界以外的模式边界位置对高原主体和东南部降水模拟的影响较小;边界层方案对降水空间形态的模拟影响较小,而对降水量级的影响较大;积云对流方案对降水空间形态和量级的影响均较大;采用15 km水平分辨率时可显著改善模式对高原主体和东南部降水的模拟水平。WRF采用适当的参数组合能较好地模拟高原主体和东南部降水的空间分布,但降水量偏大。整体而言,能较好模拟旱年降水的边界层和积云对流参数化方案组合也能较好模拟涝年降水。模式模拟的高原南侧降水偏多可能使高原南侧西风偏强,并进一步造成云南西南部降水偏多;湖南南部降水偏多可能在云南东北部至贵州地区激发出较强的气旋式环流偏差,该偏差环流在四川盆地形成异常强的偏北风,导致低纬度地区进入四川盆地的水汽偏小,从而在四川盆地形成明显的相对干偏差。因此,模式在四川盆地降水模拟能力的提高不仅要做好参数的本地化工作,还需要关注盆地以外地区的影响。For further evaluating and improving the skill of predicting extreme climate in Qinghai-Tibetan Plateau（QTP） using regional climate model（GCM）. In this paper,the Weather Research Forecast（WRF） model was used to simulate summer rainfall on the southeastern QTP for the drought（1998） and flood（2006） years with various parameters,including boundary position,cumulus convection（ CU） and planetary boundary layer（PBL） parameterization schemes,and horizontal resolution. Differences in rainfall simulated by various model parameters show that the simulated rainfall in the central and southeastern QTP is not sensitive to model boundary positions except south boundary position,but sensitive to PBL and CU parameterization schemes. Different CU parameterization schemes caused apparent differences in both spatial pattern and magnitude of simulated rainfall,while PBL parameterization schemes caused difference only in magnitude. The WRF exhibited higher skill in simulating rainfall in QTP and its adjacent areas with 15 km horizontal resolution. Overall,the simulated rainfall is strongly depended on the model horizontal resolution among the four model parameters. WRF shows better skill in simulating spatial pattern of rainfall compared to magnitude. It always produces a wet bias in central and southern QTP. Overall,the set of PBL and CU parameterization schemes shows the best skill in simulating rainfall for flood year,and also do the best for drought year. WRF has larger bias in simulating rainfall in slop of QTP compared to main body. It has an apparent dry bias in the Sichuan Basin. The dry bias is linked to the wet bias in southern Hunan,which excites an anomalous cyclone over northeastern Yunnan and Guizhou. Northeaster lies associated with the anomalous cyclone causes a reduction in water vapor entering the Sichuan Basin,resulted in an obvious relative dry bias there. The stronger than observed wester-lies to the south of QTP,associated with wet bias in south slop of QTP,causes higher than observed

关 键 词：青藏高原 WRF模式 参数敏感性 极端降水 

分 类 号：P435[天文地球—大气科学及气象学]