复杂地形条件下的热岛及局地环流特征模拟
投稿时间: 2018-02-04  最后修改时间: 2018-03-20  点此下载全文
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作者单位E-mail
王恪非 南京信息工程大学大气环境中心 348929828@qq.com 
王咏薇 南京信息工程大学大气环境中心 wyw@nuist.edu.cn 
高阳华 重庆市气象科学研究所  
何泽能 重庆市气象科学研究所  
伍见军 民航重庆空管分局  
杜钦 重庆市气象科学研究所  
陈志军 重庆市气象科学研究所  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:应用基于多层城市冠层方案BEP(Multilayer Urban Canopy Scheme)增加室内空调系统影响的建筑物能量模式BEM(Building Energy Model)方案的WRF模式,模拟研究重庆热岛的特征、成因以及局地环流对热岛形成的影响。文中共有两个算例,其一为重庆真实下垫面算例,称之为URBAN算例,其二为将城市下垫面替换为耕地下垫面的对比算例,称之为NOURBAN算例。结果表明:(1)WRF方案模拟结果与观测2m气温的对比吻合较好,误差主要出现在正午温度峰值和凌晨温度谷值处,是由于城市下垫面特性及城市内建筑分布误差所引起的差异。(2)BEP BEM方案较好地模拟出了重庆地区的热岛分布的空间和时间特征。重庆市温度的分布受地形和城市下垫面的双重影响,越靠近城区,温度的分布受城市化影响就越大,在海拔低处,温度就越高。(3)城区立体三维表面对辐射的陷阱作用导致城市表面总体反射率小,向上短波辐射小于郊区20 W?m^(-2)左右。城市表面以感热排放为主,而郊区则表现为潜热的作用占主导。夜间城市地表储热以及空调废热向大气释放,是城市热岛形成的重要原因。(4)模拟区域背景风场主要为东南风,局地环流呈现了越靠近山区风速越大,城市区域风速较小的特性,体现了城市密集的建筑群对低层大气流场的空气动力学效应,复杂山谷地形的山谷风环流特性。在市区的西侧和东南侧各有高大的山脉阻挡,山脉对城市出流的阻碍作用、气流越山与绕流运动对城市热岛的形成有一定的影响。
中文关键词:城市热岛  WRF模式  城市冠层方案  
 
Numerical Study of Urban Heat Island Characteristics and Local Circulation Under Complex Terrain Condition
Abstract:Using WRF model coupled with BEP (Multilayer Urban Canopy Scheme) and BEM(Building Energy Model) scheme, a simulation was conducted to explore characteristics, cause of Chongqing urban heat island and impact of local circulation on it. There are two simulation case conducted, one is NORMAL case which utilized real Chongqing landuse data, another is NOURBAN case which replace urban category into crop in order to understand urban impact on Chongqing heat island. Results indicated that: (1) Model produced good results compared to observation of air temperature in 2m. Errors mainly occurred at noon or night, which may because of characteristics of urban landuse and unreal building parameters. (2) BEP BEM scheme can simulated well spatial and temporal features of urban heat island. Spatial distribution of temperature is influenced by topography and city area. When closer to the city, greater temperature is affected by the urbanization. Higher temperature in lower height. (3) Urban 3D surface leads to trap effect in urban surface albedo, urban shortwave radiation is lower than which in rural terrain about 20 W?m^(-2). Sensible heat is major factor in urban energy balance however latent heat in rural area. A larger heat storage and heat released from air-conditioner is important reason for urban heat island conformation. (4) Background wind field is southeast wind in simulated area. In mountain area, wind speed is higher however in urban area there are lower wind speed. This reflect trait of rough urban land, mountain and valley wind. There are huge mountains in southeast and west city, which block the outflow from city, let background wind to climb or circle around the mountains, contributes to the enhancement of urban heat island.
keywords:urban heat island  WRF model  urban canopy scheme
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