区域气候模式对长江中下游梅雨的数值模拟:积云对流参数化方案和水平分辨率的影响  

Meiyu Simulation in the Regional Climate Model:Roles of Convective Parameterization Scheme and Horizontal Resolution

作　　者：李昊谦 王璐[1,2] 陈林 孙明[1] 葛子安[1] 程一峰 张荣华 LI Haoqian;WANG Lu;CHEN Lin;SUN Ming;GE Zian;CHENG Yifeng;ZHANG Ronghua(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Nanjing University of Information Science and Technology,Nanjing 210044;Laboratory for Regional Oceanography and Numerical Modeling,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266237;School of Marine Sciences,Nanjing University of Information Science and Technology,Nanjing 210044)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室,南京210044 [2]青岛海洋科学与技术试点国家实验室区域海洋动力学与数值模拟功能实验室,山东青岛266237 [3]南京信息工程大学海洋科学学院,南京210044

出　　处：《大气科学》2024年第6期2178-2200,共23页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42088101,42005020;江苏省优秀青年基金项目BK20230061;江苏省双创团队项目JSSCTD202346;崂山实验室科技创新项目LSKJ202202403。

摘　　要：本文研究了区域气候模式RegCM4.7对长江中下游梅雨期降水的模拟技巧,聚焦不同积云对流参数化方案、水平分辨率、微物理方案和陆面模式对梅雨降水模拟的影响及可能原因。基于区域模式中积云对流参数化方案、水平分辨率、微物理方案和陆面模式的不同配置组合,本研究共开展了96组成员试验,分析了不同模式配置方案下2020年超强梅雨个例以及1990~2020多年长江中下游梅雨期降水的模拟性能。结果发现:RegCM4.7模式在长江中下游梅雨期降水模拟方面具有一定技巧,其中积云对流参数化方案的选取对模拟结果影响较大,Tiedtke方案对梅雨降水的模拟技巧相对较高,而Grell方案相对较低。分析发现Tiedtke方案能够更合理地再现对流降水以及对流降水与层状云降水的比率,这可能是导致该方案对梅雨降水整体模拟效果较好的原因。进一步地,水平分辨率对梅雨期降水模拟的影响与地形因素有关,低水平分辨率(60 km)试验在复杂地形区域表现出显著的降水湿偏差,随着水平分辨率的提高,复杂地形带来的降水湿偏差可以明显减小。研究发现,在低分辨率试验中,中尺度对流系统(MCS)降水被长时间地锢囚在山区陡峭地形处,这将导致长时间尺度上的平均降水表现出湿偏差;而高分辨率试验能够更好地刻画复杂地形区域MCS从午后生成并逐渐向东传播的日变化特征,进而合理地再现梅雨期平均降水。最后,RegCM4.7中的微物理方案和陆面模式的选取对降水的模拟影响不大。综上,一系列数值试验结果表明区域气候模式RegCM4.7对包括2020年超强梅雨个例在内的长江中下游梅雨期降水具有较好的模拟技巧,相较而言,当RegCM4.7模式采用Tiedtke积云对流参数化时梅雨降水整体模拟技巧相对最佳,若更关注复杂地形区域的降水可考虑采用高水平分辨率配置。This study investigates the simulation skill of Meiyu precipitation over the middle and lower reaches of the Yangtze River(MLYR)using the regional climate model RegCM4.7.To examine the potential effects of cumulus convective parameterization schemes(CCPSs),horizontal resolutions(HRs),microphysics parameterizations,and land models on the simulation skill of Meiyu precipitation,we conducted 96 sets of numerical experiments based on various model configurations.In general,RegCM4.7 demonstrates good performance in simulating Meiyu precipitation over the MLYR from the perspectives of the Meiyu simulation experiments for the super Meiyu case in summer 2020 and the longterm period of 1990–2020.Our quantitative analysis reveals that CCPSs play a vital role in influencing the Meiyu simulation skill.Specifically,the Tiedtke scheme shows the best performance in simulating Meiyu precipitation,whereas the Grell scheme shows relatively low skill.The relatively reasonable simulation achieved using the Tiedtke scheme was attributed to its effective representation of convective precipitation,as well as the ratio of convective precipitation to stratiform precipitation.Furthermore,the impacts of HRs on Meiyu precipitation simulation are closely linked to the terrain.The low-HR(60 km)experiment tends to show a considerable overestimation of precipitation over regions with complex terrain.Along with the increase in HR,such wet bias of precipitation due to complex terrain can be considerably reduced.It is found that the mesoscale convective system(MCS)precipitation is anchored by steep terrain in the low-HR experiment,leading to a wet bias in the long-term average of precipitation.By contrast,the high-HR experiment replicates the diurnal variation of MCSs over the complex terrain that is generated in the afternoon and gradually propagates eastward.Such a reasonable representation of MCS features contributes to the reasonable estimation of long-term average precipitation patterns for the Meiyu season.Besides,results show that the Mei

关 键 词：梅雨模拟 RegCM4区域模式 积云对流参数化方案 模式分辨率 2020超强梅雨 

分 类 号：P456.7[天文地球—大气科学及气象学]