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Impact of the Complex Terrain in Beijing on Formation of Low-Level Jets

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Journal of Meteorological Research 2024年第1期38卷 138-150页

作者： Li’ao ZHOU Chenggang WANG shiguang miao Ju LI School of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044 Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089 Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing 100089

This study investigated how the Taihang Mountains and the Yanshan Mountains affect low-level jets(LLJs)in the Beijing area,based on conventional radiosonde observations from Nanjiao Observatory(2016–2017)and high-resolution Weather Research and Forecasting–Advanced Research WRF(WRF-ARW)model *** of radiosonde observations indicated that LLJs in the study area are mainly from the southwest and northwest directions,with occurrence frequency of 44.6%and 33.0%,***(northwest)LLJs are aligned parallel(perpendicular)to the orientation of the Taihang Mountain *** sensitivity experiments using the WRF-ARW model were then conducted to examine the effects of terrain forcing on the northwest and southwest LLJs,with adopted terrain heights of 100%and 50%.The results showed that for northwest LLJs,reduction in the elevation of the Taihang Mountain Range led to weakening of jet intensity by approximately 20%and reduction in jet maximum height by approximately 250 m;lowering the Yanshan Mountain Range had minor influence on the northwest LLJs,with only a 5.2%reduction in intensity and no substantial change in jet maximum *** southwest LLJs,reduction in the elevation of both the Taihang and Yanshan Mountain ranges resulted in minor changes in the intensity and height of the *** analysis revealed that the topography in the Beijing area could modulate the height and intensity of the stable layer by altering the inversion structure within the boundary *** LLJs can develop rapidly within the stable layer,and both the location and the scale of the jet core exhibited reasonable agreement with the extent of the stable layer.

关键词： low-level jets(LLJs) mesoscale numerical simulation terrain forcing

Comparison of Adaptive Simulation Observation Experiments of the Heavy Rainfall in South China and Sichuan Basin

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Advances in Atmospheric Sciences 2024年第11期41卷 2173-2191页

作者： Linbin HE Weiyi PENG Yu ZHANG shiguang miao Siqi CHEN Jiajing LI Duanzhou SHAO Xutao ZHANG College of Ocean and Meteorology Guangdong Ocean UniversityZhanjiang 524088China Chinese Academy of Meteorology Sciences Beijing 100081China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Dalian Marine Center Ministry of Nature Resources of the People's Republic of ChinaDalian 116001China

This study examines the effectiveness of adaptive observation experiments using the ensemble transformation sensitivity(ETS) method to improve precipitation forecasts during heavy rainfall events in South China and the Sichuan Basin. High-resolution numerical models are employed to simulate adaptive observations. By identifying the sensitive areas of key weather system positions 42 hours before heavy rainfall events, the adaptive observations improve the prediction of jet streams, strong winds, and shear lines, which are essential for accurate heavy rainfall forecasting. This improvement is reflected in both the precipitation structure and location accuracy within the verification region. In South China, targeted observations enhance rainfall predictions by improving water vapor transport. In the Sichuan Basin, adaptive observations refine water vapor transport and adjust vortex dynamics. This research highlights the importance of accurately predicting shear lines and jet streams for forecasting heavy rainfall in these areas. Overall, this study found that adaptive observation enhances the precipitation forecast skills of the structure and location for heavy rainfall in South China and the Sichuan Basin, emphasizing their potential utility in operational numerical weather prediction.

关键词： adaptive observation ensemble transform sensitivity data assimilation rainfall

Community-Level Practice Checklists for Health Protection During Cold Spells in China

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China CDC weekly 2024年第5期6卷 83-87页

作者： Jing Shang Mengzhen Zhao Zhao Liu Xiya Zhang shiguang miao Ishaq D.Sulaymon Wenjia Cai Institute of Urban Meteorology CMABeijingChina School of Management and Economics Beijing Institute of TechnologyBeijingChina School of Airport Economics and Management Beijing Institute of Economics and ManagementBeijingChina Department of Earth System Science Tsinghua UniversityBeijingChina Sand and Dust Storm Warning Regional Center National Center for MeteorologyJeddahSaudi Arabia Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing CityJiangsu ProvinceChina

Communities play a crucial role in protecting the health of vulnerable populations such as the elderly,low-income groups,and high-risk individuals during cold ***,current strategies for responding to cold spells primarily consist of programmatic policies that lack practicality,specificity,and detailed implementation guidelines for community ***,this study aims to identify and analyze the challenges faced by communities in responding to cold spells,review international experiences,and develop a set of practical checklists for community-level health *** checklists will assist community workers and volunteers in effectively preparing for,responding to,and recovering from cold spells.

关键词： preparing income primarily

华北平原及沿山和沿海五个城市夏季短历时降水过程的日变化分析

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气象学报 2024年第4期82卷 490-509页

作者：丁乙窦晶晶王迎春苗世光樊利强中国气象科学研究院北京100081 北京城市气象研究院北京100089 中国气象局城市气象重点开放实验室北京100089 国家气象中心北京100081

利用华北平原294个国家级气象站1980—2022年夏季(6—8月)逐时降水资料,分析了华北平原夏季短历时降水过程的日变化时、空分布特征,结合地面气温和风的日变化,综合分析了4个沿山城市(北京、石家庄、济南、郑州)和1个沿海城市(天津)在城... 详细信息

利用华北平原294个国家级气象站1980—2022年夏季(6—8月)逐时降水资料,分析了华北平原夏季短历时降水过程的日变化时、空分布特征,结合地面气温和风的日变化,综合分析了4个沿山城市(北京、石家庄、济南、郑州)和1个沿海城市(天津)在城市发展前期(1980—1989年)和后期(2013—2022年)短历时降水过程日变化特征及差异。结果表明:华北平原短历时降水过程整体呈现傍晚单峰的日变化特征;平原站点的达峰时间自东南向西北推后。5个主要城市在城市发展后期,短历时降水过程的日振幅都出现不同程度的减小;沿山城市短历时降水过程日峰值出现时间提前了1—2 h,而沿海城市天津无明显峰值时间,且高值时段提前;沿山城市50 mm以上短历时降水过程概率均有所升高,其中北京和石家庄40 mm以上的降水过程概率分别升高了2倍和5倍,而沿海城市天津40 mm以上的降水过程概率下降了43%。华北平原短历时降水过程的日变化与局地地形的热、动力作用和地面盛行风有关。城市局地增温效应导致沿山、沿海城市与周围地形热力差异更加明显,增强了沿山城市的山风和沿海城市的海风;同时,城市增温导致城市午后地面风辐合增强。近地面层上述热力差异变化导致的风场变化可能是沿山城市短历时降水过程日峰值提前、沿海城市短历时降水过程集中时段变为白天的重要原因。

关键词：短历时降水过程日变化城市效应地形华北平原

A rapid modeling method for urban microscale meteorology and its applications

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Science China Earth Sciences 2023年第10期66卷 2224-2238页

作者： Xiaoran GUO Chao YAN shiguang miao Institute of Urban Meteorology China Meteorological AdministrationBeijing100089China Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing100089China

This paper introduces a fast urban microscale meteorological model with a horizontal resolution of O(10)m,named URBAN(Urban Rapid&Building-Aware Neighborhood),which is capable of rapid assessment of meteorological fields over key urban areas,including wind speed,air temperature,humidity and thermal comfort index,with the execution time less than10 minutes consuming 1 CPU *** uses a fast wind diagnostic method to construct three-dimensional(3-D)wind fields surrounding complex building clusters with their geometry resolved *** enhance the accuracy of wind reconstruction and the continuity of the initial wind field around irregular buildings,we propose a new parameterization method based on stream functions,which can accurately characterize the influences of complex urban building clusters on the three-dimensional wind *** model can provide various results for the meteorological service of large outdoor activities,including conventional meteorological elements(wind,temperature,humidity,radiation,etc.)and the Universal Thermal Comfort Index,which is derived from the relationship between physiological processes and environmental meteorological *** this paper,URBAN is applied to develop an automatic analysis and forecast system of microscale meteorological elements over the central Beijing region in summer during a large outdoor *** comparing with the half-hourly observations from three auto weather stations(AWSs)in the region,the root-mean-square errors(RMSEs)of the modeled 10-meter-height wind speed,2-meter-height air temperature and humidity are 0.98 m s^(-1),1.37℃and 7.37%,respectively.

关键词： Urban microscale meteorology Wind diagnose Fast simulation Human comfort index Weather service

Multiscale modeling of the atmospheric environment over a forest canopy

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Science China Earth Sciences 2020年第6期63卷 875-890页

作者： Chao YAN shiguang miao Yujue LIU Guixiang CUI Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

Vegetation constitutes one of the fundamental types of land use on *** presence of trees in urban areas can decrease local winds and exchange sensible and latent heat with the surrounding environments,thus exerting notable influences on the urban microenvironment.A better understanding of the turbulent transfer of momentum and scalars around vegetation canopy could significantly contribute to improvement of the urban *** work develops a large-eddy simulation(LES)method that is applicable to model the flow and scalar transport over the forest *** study the atmospheric flow over complex forested areas under typical weather conditions by coupling LES to the mesoscale *** of radiation and energy balance have been developed with explicit treatment of the vegetation *** examining the flow over a forest canopy under a range of stability conditions,we found that buoyancy enhances or suppresses turbulent mixing in unstable or stable atmosphere respectively,with decreasing or increasing wind shear,*** the multiscale modeling of the Beijing Olympic Forest Park,the present coupling scheme proves to better resolve the diurnal variations in wind speed,temperature,and relative humidity over complex urban *** coupling scheme is superior to the traditional mesoscale model in terms of wind field *** is mainly because the coupling scheme not only takes the influences of external mesoscale flow into consideration,but also resolves the heterogeneous urban surface at a fine scale by downscaling,thus better reproducing the complex flow and turbulent transport in the urban roughness sublayer.

关键词： Urban forest environment Canopy turbulence Large eddy simulation Multiscale modeling

Numerical simulation of the influence of aerosol radiation effect on urban boundary layer

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Science China Earth Sciences 2018年第12期61卷 1844-1858页

作者： Xinran WANG Xiaodong HE shiguang miao Youjun DOU China Institute of Atomic Energy Beo'ing 102413China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China

With the intensification of pollution and urbanization, the aerosol radiation effect continues to play an important role in the urban boundary layer. In this paper, a winter pollution process in Beijing has been taken as an example, and a new aerosol vertical profile in the radiative parameterization scheme within the Weather Forecast Research and Forecasting(WRF) model has been updated to study the effect of aerosols on radiation and the boundary layer. Furthermore, the interactions among aerosols,urbanization, and planetary boundary layer(PBL) meteorology were discussed through a series of numerical experiments. The results show the following:(1) The optimization improves the performance of the model in simulating the distribution features of air temperature, humidity, and wind in Beijing.(2) The aerosols reduce the surface temperature by reducing solar radiation and increasing the temperature in the upper layer by absorbing or backscattering solar radiation. The changes in the PBL temperature lead to more stable atmospheric stratification, reducing the energy transfer from the surface and the height of the boundary layer.(3) With the increase in the aerosol optical depth, the atmospheric stratification most likely becomes stable over rural areas, most likely becomes stable over suburb areas, and has great difficultly becoming stable over urban areas. Aerosol radiative forcing,underlying urban surfaces, and the interaction between them are the main factors that affect the changes in the meteorological elements in the PBL.

关键词： Aerosol Urbanization Boundary layer Meteorological elements WRF

A Microscale Model for Air Pollutant Dispersion Simulation in Urban Areas： Presentation of the Model and Performance over a Single Building

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Advances in Atmospheric Sciences 2016年第2期33卷 184-192页

作者： Ning ZHANG Yunsong DU shiguang miao Institute for Climate and Global Change Research and School of Atmospheric Sciences Nanjing University Nanjing 210093 Sichuan Environmental Monitoring Center Chengdu 610091 Institute of Urban Meteorology China Meteorological Administration Beijing 100089

A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model＇s performance, using CEDVAL （Compilation of Experimental Data for Validation of Microscale Disper- sion Models） wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios; and the assessment of microscale air quality in urban areas.

关键词： numerical model urban air pollution air pollutant dispersion emergency response model

Evaluation of a Micro-scale Wind Model's Performance over Realistic Building Clusters Using Wind Tunnel Experiments

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Advances in Atmospheric Sciences 2016年第8期33卷 969-978页

作者： Ning ZHANG Yunsong DU shiguang miao Xiaoyi FANG Institute for Climate and Global Change Research and School of Atmospheric Sciences Nanjing UniversityNanjing 210093 Sichuan Environmental Monitoring Center Chengdu 610091 Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089 Beijing Municipal Climate Center Beijing 100089

The simulation performance over complex building clusters of a wind simulation model（Wind Information Field Fast Analysis model, WIFFA） in a micro-scale air pollutant dispersion model system（Urban Microscale Air Pollution dispersion Simulation model, UMAPS） is evaluated using various wind tunnel experimental data including the CEDVAL（Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models） wind tunnel experiment data and the NJU-FZ experiment data（Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data）. The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution（1–5 m） wind fields of a complex neighborhood scale urban building canopy（～ 1 km ×1km） in less than 3 min when run on a personal computer.

关键词： numerical model urban wind field wind tunnel experiment data emergency response model