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Characteristics of Near Surface Winds over Different Underlying Surfaces in china: Implications for Wind Power Development

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Journal of meteorological research 2019年第2期33卷 349-362页

作者： Xi GONG Rong ZHU Lianshou CHEN Nanjing University of Information Science & Technology Chinese Academy of meteorological Sciences National Climate Center china meteorological administration

Accurate wind and turbulence information are essential to wind energy research and utilization, among which wind shear and turbulence intensity/scale have seldom been investigated. In this paper, the observational data from the100-m high wind towers in Xilinhot in Inner Mongolia(2009–10; grassland region), Huanghua in Hebei Province(2009–10; coastal flat region), and Xingzi County in Jiangxi Province(2010–11; mountain–lake region) are used to study the variations in near surface winds and turbulence characteristics related to the development of local wind energy over different underlying surfaces. The results indicate that(1) the percentage of the observed wind shear exponents exceeding 0.3 for the grassland region is 6%, while the percentage is 13% for the coastal flat region and 10%for the mountain–lake region. In other words, if the wind speed at 10 m is 10 ms^(–1), the percentage of the wind speed at 100 m exceeding 20 ms^(–1) for the grassland region is 6%, while the percentage is 13% for the coastal flat region and 10% for the mountain–lake region.(2) In terms of the turbulent intensity in the zonal, meridional, and vertical directions(I_u, I_v, and I_w, respectively), the frequencies of I_v/I_u < 0.8 in the grassland, coastal flat, and mountain–lake regions are 23%–29%, 32%–38%, and 30%–37%, respectively. Additionally, the frequencies of I_w/I_u < 0.5 in the grassland, coastal flat, and mountain–lake regions are 45%–75%, 52%–70%, and 43%–53%, respectively. The frequencies of I_v/I_u < 0.8 and Iw/I_u < 0.5 in each region mean that I_u is large and the air flow is unstable and fluctuating,which will damage the wind turbines. Therefore, these conditions do not meet the wind turbine design requirements,which must be considered separately.(3) At 50-and 70-m heights, the value of the turbulence scale parameter Λ in the grassland region is greater than that in the coastal flat region, and the latter is greater than that in the mountain–lake region. Therefore, under

关键词： wind energy underlying surface wind shear exponent turbulence turbulent intensity

Development of a Global Historic Monthly Mean Precipitation Dataset

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Journal of meteorological research 2016年第2期30卷 217-231页

作者：杨溯徐文慧许艳李庆祥 National meteorological Information Center China Meteorological Administration

Global historic precipitation dataset is the base for climate and water cycle *** have been several global historic land surface precipitation datasets developed by international data centers such as the US National Climatic Data Center(NCDC),European Climate Assessment & Dataset project team,Met Office,etc.,but so far there are no such datasets developed by any research institute in *** addition,each dataset has its own focus of study region,and the existing global precipitation datasets only contain sparse observational stations over china,which may result in uncertainties in East Asian precipitation *** order to take into account comprehensive historic information,users might need to employ two or more ***,the non-uniform data formats,data units,station IDs,and so on add extra difficulties for users to exploit these *** this reason,a complete historic precipitation dataset that takes advantages of various datasets has been developed and produced in the National meteorological Information Center of *** observations from 12 sources are aggregated,and the data formats,data units,and station IDs are *** stations with the same ID are identified,with duplicated observations *** test,correlation coefficient test,significance t-test at the95%confidence level,and significance F-test at the 95%confidence level are conducted first to ensure the data *** those datasets that satisfy all the above four criteria are integrated to produce the china meteorological administration global precipitation(CGP) historic precipitation dataset version *** contains observations at 31 thousand stations with 1.87 x 107 data records,among which 4152 time series of precipitation are longer than 100 *** dataset plays a critical role in climate research due to its advantages in large data volume and high density of station network,compared to other *** the Penalized Maximal

关键词： global precipitation observation historic data

Construction and Validation of an Urban Area Flow and Dispersion Model on Building Scales

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Acta meteorologica Sinica 2013年第6期27卷 923-941页

作者：陈笔澄刘树华缪育聪王姝李源 Department of Atmospheric and Oceanic Sciences School of PhysicsPeking University

This paper presents a numerical model that simulates the wind fields, turbulence fields, and dispersion of gaseous substances in urban areas on building to city block scales. A Computational Fluid Dynamics（CFD） approach using the steady-state, Reynolds-Averaged Navier-Stokes（RANS） equations with the standard k-ε turbulence model within control volumes of non-uniform cuboid shapes has been employed. Dispersion field is computed by solving an unsteady transport equation of passive scalar. Another approach based on Gaussian plume model is used to correct the turbulent Schmidt number of tracer, in order to improve the dispersion simulation. The experimental data from a wind tunnel under neutral conditions are used to validate the numerical results of velocity, turbulence, and dispersion fields. The numerical results show a reasonable agreement with the wind tunnel data. The deviation of concentration between the simulation with corrected turbulent Schmidt number and the wind tunnel experiments may arise from 1） imperfect point sources, 2） heterogeneous turbulent difusivity, and 3） the constant turbulent Schmidt assumption used in the model.

关键词： urban areas flow and dispersion computational fluid dynamics RANS equation k-ε model turbulent Schmidt number

Numerical study of the effects of local atmospheric circulations on a pollution event over Beijing–Tianjin–Hebei, china

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Journal of Environmental Sciences 2015年第4期27卷 9-20页

作者： Yucong Miao Shuhua Liu Yijia Zheng Shu Wang Bicheng Chen Hui Zheng Jingchuan Zhao Department of Atmospheric and Oceanic Sciences School of Physics Peking University Department of Meteorology The Pennsylvania State University University Park Key Laboratory of Regional Climate–Environment research for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Department of Atmospheric Sciences Yunnan University

Currently, the Chinese central government is considering plans to build a trilateral economic sphere in the Bohai Bay area, including Beijing, Tianjin and Hebei（BTH）, where haze pollution frequently occurs. To achieve sustainable development, it is necessary to understand the physical mechanism of the haze pollution there. Therefore, the pollutant transport mechanisms of a haze event over the BTH region from 23 to 24 September 2011 were studied using the Weather research and Forecasting model and the FLEXible-PARTicle dispersion model to understand the effects of the local atmospheric circulations and atmospheric boundary layer structure. Results suggested that the penetration by sea-breeze could strengthen the vertical dispersion by lifting up the planetary boundary layer height（PBLH） and carry the local pollutants to the downstream areas; in the early night, two elevated pollution layers（EPLs） may be generated over the mountain areas： the pollutants in the upper EPL at the altitude of 2–2.5 km were favored to disperse by long-range transport, while the lower EPL at the altitude of 1 km may serve as a reservoir, and the pollutants there could be transported downward and contribute to the surface air *** intensity of the sea–land and mountain–valley breeze circulations played an important role in the vertical transport and distribution of pollutants. It was also found that the diurnal evolution of the PBLH is important for the vertical dispersion of the pollutants,which is strongly affected by the local atmospheric circulations and the distribution of urban areas.

关键词： Air pollution Sea–land breeze circulation Mountain–valley breeze circulation WRF model FLEXPART model

Numerical study of the effects of Planetary Boundary Layer structure on the pollutant dispersion within built-up areas

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Journal of Environmental Sciences 2015年第6期27卷 168-179页

作者： Yucong Miao Shuhua Liu Yijia Zheng Shu Wang Zhenxin Liu Bihui Zhang Department of Atmospheric and Oceanic Sciences School of Physics Peking University International Center of Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences National meteorological Center China Meteorological Administration

The effects of different Planetary Boundary Layer（PBL） structures on pollutant dispersion processes within two idealized street canyon configurations and a realistic urban area were numerically examined by a Computational Fluid Dynamics（CFD） model. The boundary conditions of different PBL structures/conditions were provided by simulations of the Weather researching and Forecasting model. The simulated results of the idealized 2D and 3D street canyon experiments showed that the increment of PBL instability favored the downward transport of momentum from the upper flow above the roof to the pedestrian level within the street canyon. As a result, the flow and turbulent fields within the street canyon under the more unstable PBL condition are stronger. Therefore, more pollutants within the street canyon would be removed by the stronger advection and turbulent diffusion processes under the unstable PBL condition. On the contrary, more pollutants would be concentrated in the street canyon under the stable PBL condition. In addition, the simulations of the realistic building cluster experiments showed that the density of buildings was a crucial factor determining the dynamic effects of the PBL structure on the flow patterns. The momentum field within a denser building configuration was mostly transported from the upper flow, and was more sensitive to the PBL structures than that of the sparser building configuration. Finally, it was recommended to use the Mellor-Yamada-Nakanishi-Niino（MYNN） PBL scheme, which can explicitly output the needed turbulent variables, to provide the boundary conditions to the CFD simulation.

关键词： Weather researching and Forecasting model Planetary Boundary Layer Computational Fluid Dynamics Open FOAM Dispersion

Advances in Studies of Cloud Overlap and Its Radiative Transfer in Climate Models

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Journal of meteorological research 2016年第2期30卷 156-168页

作者：张华荆现文 Laboratory for Climate Studies National Climate CenterChina Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science & Technology

The latest advances in studies on the treatment of cloud overlap and its radiative transfer in global climate models are *** with respect to this internationally challenging problem are described from aspects such as the design of cloud overlap assumptions,the realization of cloud overlap assumptions within climate models,and the data and methods used to obtain consistent observations of cloud overlap structure and radiative transfer in overlapping *** date,there has been an appreciable level of achievement in studies on cloud overlap in climate models,demonstrated by the development of scientific assumptions（e.g.,e-folding overlap） to describe cloud overlap,the invention and broad application of the fast radiative transfer method for overlapped clouds（Monte Carlo Independent Column Approximation）,and the emergence of continuous 3D cloud satellite observation（e.g.,CloudSat/CALIPSO） and cloud-resolving models,which provide numerous data valuable for the exact description of cloud overlap structure in climate ***,present treatments of cloud overlap and its radiative transfer process are far from complete,and there remain many unsettled problems that need to be explored in the future.

关键词： cloud overlap climate model parameterization

Impacts of Land-Use Data on the Simulation of Surface Air Temperature in Northwest china

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Journal of meteorological research 2018年第6期32卷 896-908页

作者： Yaohui LI Cailing ZHAO Tiejun ZHANG Wei WANG Haixia DUAN Yuanpu LIU Yulong REN Zhaoxia PU Key Laboratory for Arid Climate Change and Disaster Reduction of Gansu Province Lanzhou Institute of Arid Meteorology/Northwestern Regional Center of Numerical Weather Prediction Key Open Laboratory for Arid Climate Change and Disaster Reduction of the China Meteorological Administration Department of Atmospheric Sciences University of Utah

This study examines the impacts of land-use data on the simulation of surface air temperature in Northwest china by the Weather research and Forecasting(WRF) model. International Geosphere–Biosphere Program(IGBP) landuse data with 500-m spatial resolution are generated from Moderate Resolution Imaging Spectroradiometer(MODIS)satellite products. These data are used to replace the default U.S. Geological Survey(USGS) land-use data in the WRF model. Based on the data recorded by national basic meteorological observing stations in Northwest china, results are compared and evaluated. It is found that replacing the default USGS land-use data in the WRF model with the IGBP data improves the ability of the model to simulate surface air temperature in Northwest china in July and December 2015. Errors in the simulated daytime surface air temperature are reduced, while the results vary between seasons. There is some variation in the degree and range of impacts of land-use data on surface air temperature among seasons. Using the IGBP data, the simulated daytime surface air temperature in July 2015 improves at a relatively small number of stations, but to a relatively large degree; whereas the simulation of daytime surface air temperature in December 2015 improves at almost all stations, but only to a relatively small degree(within 1°C). Mitigation of daytime surface air temperature overestimation in July 2015 is influenced mainly by the change in ground heat flux. The modification of underestimated temperature comes mainly from the improvement of simulated net radiation in December 2015.

关键词： surface air temperature land-use data numerical simulation Northwest china

Retrieval of Atmospheric Temperature and Moisture Vertical Profiles from Satellite Advanced Infrared Sounder Radiances with a New Regularization Parameter Selecting Method

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Journal of meteorological research 2016年第3期30卷 356-370页

作者：张堃吴春强李俊 Chinese Academy of meteorological Sciences Beijing 100081China National Satellite meteorological Center Beijing 100081China Cooperative Institute for meteorological Satellite Studies University of Wisconsin-MadisonMadisonWI 53706USA

Considering the characteristics of nonlinear problems,a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variational analysis-based sounding retrieval *** the first iteration,this method uses an empirical regularization parameter derived by minimizing the entropy of *** subsequent iterations,it uses the L-curve method to select the regularization parameter in the vicinity of the regularization parameter selected in the last *** new method was employed to select the regularization parameter in retrieving atmospheric temperature and moisture profiles from Atmospheric Infrared Sounder radiance measurements selected from the first day of each month in *** results show that compared with the original L-curve method,the new method yields 5.5%and 2.5%improvements on temperature and relative humidity profiles,*** with the discrepancy principle method,the improvements on temperature and relative humidity profiles are 1.6%and 2.0%,respectively.

关键词： Atmospheric Infrared Sounder retrieval entropy L-curve regularization parameter

Numerical Study of the Evolution of a Sea-Breeze Front Under Two Environmental Flows

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Journal of meteorological research 2015年第3期29卷 446-466页

作者：梁钊明王东海 State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences

The evolution of a sea-breeze front （SBF） in parallel and offshore environmental flows was investigated by using high-resolution simulations of two SBF cases from the Bohai Bay region, china. The results show that the combination of a distinct vertical wind shear caused by the sea-breeze circulation with a neutral or slightly stable atmospheric stratification associated with the thermal inner boundary layer promoted the occurrence and maintenance of a Kelvin-Helmholtz billow （KHB）. In a parallel environmental flow, the SBF evolved into a few connected segments because of the inhomogeneity of the sea-breeze direction and intensity as it penetrated inland. A significant upward vertical motion occurred at the two ends of the SBF segment owing to the sea-breeze convergence and was accelerated by the KHB. The KHB made a notable contribution to the intensity at the ends of the segment, whereas the intensity at the middle segment was primarily attributed to the convergence between the sea breeze and the parallel flow. In the offshore environmental flow, the clockwise rotation of the offshore flow varying with time increased the downstream convergence of the interface between the sea breeze and the offshore flow and pushed the downstream convergence zone to an orientation consistent with the offshore flow. The air parcels ascending from the downstream part of the SBF were continuously lifted by the downstream convergence zone during their advection, leading to a significant downstream development of the SBF. The significant upward vertical motion caused by the sea-breeze convergence behind the upstream end of the SBF was shifted to the upstream end of the SBF by the KHB, which enhanced the intensity of the upstream end of the SBF.

关键词： sea-breeze front environmental flow numerical study Kelvin-Helmholtz billow