不同的边界层参数化方案对江淮一次暴雨过程数值试验研究
投稿时间:2017-12-04  修订日期:2018-10-09  点此下载全文
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周彦均 南京信息工程大学 应用气象学院, 江苏 南京 210044
安徽省气象局 中国气象局气象干部培训学院安徽分院, 安徽 合肥 230000 
 
高志球 南京信息工程大学 应用气象学院, 江苏 南京 210044
中国科学院 大气物理研究所 大气边界层物理和大气化学国家重点实验室, 北京 100029 
zgao@mail.iap.ac.cn 
濮梅娟 江苏省气象局, 江苏 南京 210008  
李煜斌 南京信息工程大学 应用气象学院, 江苏 南京 210044  
基金项目:国家重点研发计划项目(2018YFC1506405)
中文摘要:利用WRF模式分别耦合YSU、MYJ、ACM2和MRF边界层参数化方案对长江中下游地区2013年7月的一次暴雨个例进行模拟实验。为了检验边界层参数化方案的重要性,研究使用无边界层方案(NOPBL)的WRF模式对这次暴雨进行了模拟。通过与实测数据进行对比和分析,本文检验了这五种不同的实验设计对降水落区、总量、基本气象要素的模拟能力。综合模拟结果表明,不同的边界层参数化方案模拟的结果不同。不论是否使用边界层参数化方案,均能模拟出雨带的基本走向,但不同的方案对降水中心强度及位置的模拟与实况相比有差异。NOPBL产生了最大的偏差,ACM2和MRF次之,MYJ的方案对于小雨与大雨的模拟最优,而YSU对不同强度暴雨模拟的正确率都较高。通过物理量分析对比,MYJ方案较优的原因是:1)风场检测,MYJ方案的模拟结果更接近观测值;2)850 hPa水汽通量散度检测,MYJ方案能够模拟两支水汽输送通道。一支以偏西南风为主,在急流出口区有较强的南风风速辐合,使得从西南方向来的水汽向暴雨区辐合;另一支将偏东水汽向西部输送,保证暴雨区局部辐合。3)垂直速度检测,MYJ,YSU方案模拟的垂直运动中心与降水落区相近,但YSU模拟上升速度偏大,相对而言MYJ方案更合理。
中文关键词:数值模拟  边界层参数化方案  降水  WRF模式
 
Impact of different planetary boundary layer parameterization schemes on the simulation of a rainstorm event over the Yangtzi River Basin
Abstract:In this study,by using the Weather Research and Forecasting(WRF) model with five different planetary boundary layer options(no planetary boundary layer scheme,Yonsei University scheme,Mellor-Yamada-Janjic scheme,asymmetric convective version 2 scheme and medium-range forecast scheme),a rainstorm which occurred in July 2013 in the Yangtze River area was simulated.Through comparison with the observation data,the respective simulation capabilities of the five different experimental designs were evaluated.Then their simulated precipitation area,total rainfall amount,and basic meteorological elements were analyzed.The observations show that the simulated results obtained using the various schemes are different.The rain band's general trend can be accurately simulated,regardless of whether or not the PBL parameterization schemes are used,yet the simulations of the intensity and location of the rainfall center differ to some extent.The largest rainfall simulation bias occurs in the experiments performed without the planetary boundary layer scheme,while the experiments performed with the asymmetric convective version 2 and medium-range forecast schemes produce better rainfall simulations.In particular,the experiment using the Mellor-Yamada-Janjic scheme yields the best simulation results for small and large rainfall,while when coupled with the Yonsei University scheme,the model yields the highest threat score (TS) for the simulation of rainfall with various intensities.Through the analysis and comparison of various physical quantities,the following conclusions are drawn:1)Compared to the other schemes,the simulation results of the MYJ scheme are closer to the observed values;2)The MYJ scheme can simulate two water vapor transport channels:one is dominated by southwesterly wind,with strong convergence of south wind speed at the exit of the jet stream,which drives the water vapor coming from the southwest converge to the rainstorm area;while the second conveys the water vapor from east to west to ensure the local convergence of the rainstorm area;and 3)The vertical motion center and precipitation area from the MYJ and YSU schemes are similar,but the YSU-simulated rising speed is larger,thus in comparison the MYJ scheme is more reasonable.
keywords:numerical simulation  planetary boundary layer parameterizations  precipitation  WRF model
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