冬奥会小海坨山赛区边界层风场大涡模拟研究  

Large Eddy Simulation of Flow Field over the Xiaohaituo Mountain Division for the 24^(th) Winter Olympic Games

作　　者：刘郁珏 苗世光[1] 胡非[2] 刘玉宝 LIU Yujue;MIAO Shiguang;HU Fei;LIU Yubao(Institute of Urban Meteorology,China Meteorology Administration,Beijing 100089,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;Research Application Laboratory,National Center for Atmospheric Research,Boulder.Colorado 80307.America)

机构地区：[1]中国气象局北京城市气象研究所,北京100089 [2]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(LAPC),北京100029 [3]美国国家大气研究中心(NCAR)

出　　处：《高原气象》2018年第5期1388-1401,共14页Plateau Meteorology

基　　金：国家自然科学基金项目(41705006;11472272);北京市科技计划项目(D171100000717003);北京市自然科学基金项目(8184074)

摘　　要：北京市延庆区小海坨山将承担2022年第24届冬季奥运会部分高山滑雪、高山速降等室外赛事。由于室外赛事对近地面风场有着极其严格要求,需要提供百米内分辨率风预报产品。目前广泛使用的高分辨率(>1 km)中尺度模式尚不能满足这一预报需求。本文基于中尺度气象模式(WRF)的大涡模拟(LES)功能,针对冬奥小海坨山地区构建在线耦合中-微尺度WRF-LES模式系统,采用四重单向嵌套将水平分辨率从中尺度1 km降至微尺度37 m,对发生在该地区2017年1月13日晴天大风个例开展边界层风场的精细模拟。结合观测,通过设计模式水平、垂直、地形分辨率及边界层方案敏感性试验,检验和评估了WRF-LES作为真实大气模拟工具在复杂地形区域的适用性。结果表明,由于LES能解析大气湍流中部分湍涡能量,相比普通中尺度模式WRF,百米或更高分辨率WRF-LES能捕捉更多大气小尺度运动特征,刻画出局地流场结构,获得更精细、准确的近地面风场信息。为实现精确模拟,模式需引入与水平分辨率相匹配的高分辨率地形高程数据,结合计算资源能力设置垂直网格距。模拟结果表明WRF-LES对复杂山地近地面风场具有超高分辨率模拟应用的潜力和价值,表现出较好的预报能力,可为冬奥会精细气象服务提供技术支持。Competitions for luge,bobsleigh and alpine skiing of the 24 th Winter Olympic Games in February2022 will be held in Xiaohaituo Mountain area northwest of Beijing,90 kilometers away from the downtown.The outdoor events are very strict on the near-surface wind fields.Therefore,it is necessary to provide wind field prediction within 100 meters resolution.At present,the widely used mesoscale models,limited by their grid resolution（1 km）,cannot meet the needs.This paper described a multi-scale weather modeling system,WRF-LES,which employs large-eddy simulation（LES） with the WRF model.The system was employed to simulate real-world conditions of a typical clear day with strong winds over Xiaohaituo mountain area.With four nested domains,the horizontal grid spacing is decreased from 1 km to 37 m.Through a group of sensitivity tests of horizontal,vertical,terrain resolution and boundary layer schemes,the applicability of WRF-LES has been evaluated and tested against in-situ observation from MOUNTOAM（Mountain Terrain Atmospheric Observations and Modeling） filed campaign.Compared to ordinary mesoscale model,100 meters or higher resolution WRF-LES results were found to capture more microscale flows owing to its explicit resolving of large atmospheric turbulence eddies,and obtain wind field flowmore resemble the real atmosphere.For accurate simulation,the topographygraphic data should be matched with the model horizontal resolution,and the vertical grid spacing needs to be carefully set.For this case,WRFLES has the potential and value for the ultra-high-resolution simulation of the near-surface wind field over complex mountainous area.It shows high forecasting ability,and can provide technical support for fine weather service in Winter Olympic Games.

关 键 词：中尺度模式 大涡模拟 复杂地形 大气边界层 冬奥会 

分 类 号：P404[天文地球—大气科学及气象学]