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Effects of Dynamic Vegetation on Global Climate Simulation Using the NCEP GFS and SSiB4/TRIFFID

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Journal of Meteorological Research 2021年第6期35卷 1041-1056页

作者： Zhengqiu ZHANG yongkang xue Panmao ZHAI Huiping DENG Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081China University of California Los AngelesCA 90095USA Liaocheng University Liaocheng 252059China

Two global experiments were carried out to investigate the effects of dynamic vegetation processes on numerical climate simulations from 1948 to *** NCEP Global Forecast System(GFS)was coupled with a biophysical model,the Simplified Simple Biosphere Model(SSi B)version 2(GFS/SSi B2),and it was also coupled with a biophysical and dynamic vegetation model,SSi B version 4/Top-down Representation of Interactive Foliage and Flora Including Dynamics(TRIFFID)(GFS/SSi B4/TRIFFID).The effects of dynamic vegetation processes on the simulation of precipitation,near-surface temperature,and the surface energy budget were identified on monthly and annual scales by assessing the GFS/SSi B4/TRIFFID and GFS/SSi B2 results against the satellite-derived leaf area index(LAI)and albedo and the observed land surface temperature and *** results show that compared with the GFS/SSiB2 model,the temporal correlation coefficients between the globally averaged monthly simulated LAI and the Global Inventory Monitoring and Modeling System(GIMMS)/Global Land Surface Satellite(GLASS)LAI in the GFS/SSi B4/TRIFFID simulation increased from 0.31/0.29(SSiB2)to 0.47/0.46(SSiB4).The correlation coefficients between the simulated and observed monthly mean near-surface air temperature increased from 0.50(Africa),0.35(Southeast Asia),and 0.39(South America)to 0.56,0.41,and 0.44,*** correlation coefficients between the simulated and observed monthly mean precipitation increased from 0.19(Africa),0.22(South Asia),and 0.22(East Asia)to 0.25,0.27,and 0.28,*** greatest improvement occurred over arid and semiarid *** spatiotemporal variability and changes in vegetation and ground surface albedo modeled by the GFS with a dynamic vegetation model were more consistent with the *** dynamic vegetation processes contributed to the surface energy and water balance and in turn,improved the annual variations in the simulated regional temperature and precipita

关键词： NCEP Global Forecast System(GFS) Simplified Simple Biosphere Model version 4/Top-down Representation of Interactive Foliage and Flora Including Dynamics(SSiB4/TRIFFID) global climate simulation effects of dynamic vegetation

Assessment of Dynamic Downscaling of the Extreme Rainfall over East Asia Using a Regional Climate Model

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Advances in Atmospheric Sciences 2011年第5期28卷 1077-1098页

作者：高艳红 yongkang xue 彭雯 Hyun—Suk KANG Duane WALISER Laboratory for Climate Environment and Disasters of Western ChinaCold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 Department of Geography and Department of Atmospheric and Oceanic Sciences University of California Los Angeles California USA Climate Research Laboratory National Institute of Meteorological Research Korea Meteorological Administration Korea Jet Propulsion Laboratory/California Institute of Technology California USA

This study investigates the capability of the dynamic downscaling method （DDM） in an East Asian climate study for June 1998 using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research non-hydrostatic Mesoscale Model （MM5）.Sensitivity experiments show that MM5 results at upper atmospheric levels cannot match reanalyses data,but the results show consistent improvement in simulating moisture transport at low *** downscaling ability for precipitation is regionally *** the monsoon season over the Yangtze River basin and the pre-monsoon season over North China,the DDM cannot match observed *** Northwest China and the Tibetan Plateau （TP）,where there is high topography,the DDM shows better performance than *** monsoon evolution processes over East Asia,however,are much closer to observational data than *** convection scheme has a substantial impact on extreme rainfall over the Yangtze River basin and the pre-monsoon over North China,but only a marginal contribution for Northwest China and the *** surface parameterizations affect the locations and pattern of rainfall *** 10-day re-initialization in this study shows some improvement in simulated precipitation over some sub-regions but with no obvious improvement in *** setting of the location of lateral boundaries （LLB） westward improves performance of the *** the entire TP in the western model domain improves the DDM performance in simulating precipitation in most *** addition,a seasonal simulation demonstrates that the DDM can also obtain consistent results,as in the June case,even when another two months consist of no strong climate/weather events.

关键词： DDM MM5 cumulus convection scheme land parameterization re-initialization lateral boundary location

Numerical Investigation and Uncertainty Analysis of Eastern China's Large-Scale Urbanization Effect on Regional Climate

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Journal of Meteorological Research 2021年第6期35卷 1023-1040页

作者： Jiping QUAN yongkang xue Qingyun DUAN Zhenxin LIU Keith WOLESON Ye LIU Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China Department of Geography University of CaliforniaLos AngelesCA 90095USA Department ofAtmospheric&Oceanic Sciences University of CaliforniaLos AngelesCA 90095USA State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Hydrology and Water ResourcesHohai UniversityNanjing 210098China School of Environmental Science and Engineering Nanjing University of Information Science&TechnologyNanjing 210044China National Center for Atmospheric Research BoulderCO 80307USA

Eastern China has experienced rapid urbanization during the past four decades,and it is necessary to understand the impacts of the urbanization on the regional *** simulations with either regional climate models(RCMs)or general circulation models have produced inconsistent and statistically non-significant urbanization effects on precipitation during the East Asian summer *** the studies with RCMs,reanalysis data were used as the lateral boundary conditions(LBCs)for both urban and non-urban *** the same LBCs may limit the urbanization effect,in this study,the Weather Research and Forecasting(WRF)model nested within the Global Forecast System(GFS),both of which were coupled with an urban canopy model,were used to explore the urbanization effect over eastern *** WRF’s LBCs in the runs with/without urbanization were provided by the corresponding GFS runs with/without *** results showed a significant decrease in precipitation over North China,mainly due to a marked decrease in evaporation and the divergence induced by the reduced latent heating in the mid and upper atmosphere,from the experiment with ***,to the north and south of the large-scale urbanization areas,especially to the south of the Yangtze River,precipitation increased significantly due to largescale urbanization-induced circulation *** the same LBCs for the WRF runs with/without urbanization,the urbanization effects were limited only to urban and nearby areas;no significant change was found to the south of the Yangtze River,since the same LBCs hampered the effects of urbanization on large-scale *** addition,this study demonstrated that the urban fraction may be a key factor that affects the intensity of the urbanization effect within the urban areas.

关键词： urbanization effect regional climate model uncertainty analysis lateral boundary condition urban fraction

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Chinese Journal of Aeronautics 2008年第6期21卷 512-517页

作者： Li Yulong Zhang yongkang xue Pu School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China

With dimensional analysis and similarity theory, the model similarity law of aircraft structures trader bird impact load is investigated. Numerical calculations by means of nonlinear dynamic software ANSYS/LS-DYNA are conducted on the finite element models constructed with different scaling factors. The influence of strain rate on the model similarity law is found to be dependent on the strain rate sensitivity of materials and scale factors. Specifically, materials that are not sensitive to strain rate obey the model similarity law in the bird impact process. The conclusions obtained are supposed to provide a theoretical basis for the experimental work of bird impact on aircraft structure.

关键词： dimensional analysis similarity law bird impact strain rate finite element analysis

Four-stream Radiative Transfer Parameterization Scheme in a Land Surface Process Model

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Acta meteorologica Sinica 2009年第1期23卷 105-115页

作者：周文艳郭品文罗勇 Kuo-Nan LIOU Yu GU yongkang xue Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing 100081 China Nanjing University of Information Science ＆ Technology Nanjing 210044 China University of California at Los Angeles Los Angeles CA 90095 USA

Accurate estimates of albedos are required in climate modeling. Accurate and simple schemes for radiative transfer within canopy are required for these estimates, but severe limitations exist. This paper developed a four-stream solar radiative transfer model and coupled it with a land surface process model. The radiative model uses a four-stream approximation method as in the atmosphere to obtain analytic solutions of the basic equation of canopy radiative transfer. As an analytical model, the four-stream radiative transfer model can be easily applied efficiently to improve the parameterization of land surface radiation in climate models. Our four-stream solar radiative transfer model is based on a two-stream short wave radiative transfer model. It can simulate short wave solar radiative transfer within canopy according to the relevant theory in the atmosphere. Each parameter of the basic radiative transfer equation of canopy has special geometry and optical characters of leaves or canopy. The upward or downward radiative fluxes are related to the diffuse phase function, the G-function, leaf reflectivity and transmission, leaf area index, and the solar angle of the incident beam. The four-stream simulation is compared with that of the two-stream model. The four-stream model is proved successful through its consistent modeling of canopy albedo at any solar incident angle. In order to compare and find differences between the results predicted by the four- and two-stream models, a number of numerical experiments are performed through examining the effects of different leaf area indices, leaf angle distributions, optical properties of leaves, and ground surface conditions on the canopy albedo. Parallel experiments show that the canopy albedos predicted by the two models differ significantly when the leaf angle distribution is spherical and vertical. The results also show that the difference is particularly great for different incident solar beams. One additional exp

关键词： radiative transfer equation four-stream approximation four-stream radiative transfer model

Analysis of Tidal Current Energy Potential in the Major Channels of the Bohai Strait Based on Delft3D

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Journal of Ocean University of China 2024年第4期23卷 859-870页

作者： MA Pengcheng SHI Hongyuan xue Huaiyuan LI Pingping SUN yongkang School of Hydraulic Engineering Ludong University of ChinaYantai 264025China Institute of Coastal Research Ludong University of ChinaYantai 264025China Yantai Kekan Marine Technology Co. Ltd.Yantai 264025China

The utilization and development of tidal current energy can help alleviate the current energy shortage,improve the global ecological environment,and maintain sustainable *** this study,numerical simulation is carried out on a rectangular grid using *** tidal current energy potential of the major channels in the Bohai Strait is further simulated and estimated by comparing the simulated and measured *** show that the flow module in Delft3D has good modeling ability for the assessment of tidal current energy *** average flow velocity,maximum flow velocity,and energy flow density are *** Laotieshan Channel,located in the northern part of the Bohai Strait,shows a large tidal current energy *** maximum flow velocity of this channel can reach 2 m s-1,and the maximum energy flow density can exceed 500 W *** tidal current energy in the Laotieshan Channel is more than 10 times that in other ***,this study advocates for the continued exploration and exploitation of the tidal current energy resources in the Laotieshan Channel.

关键词： Delft3D Bohai Strait tidal current energy numerical simulation power density

Vegetation greening in China and its effect on summer regional climate

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Science Bulletin 2021年第1期66卷 13-17,M0003页

作者： Lingxue Yu yongkang xue Ismaila Diallo Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China Department of Geography University of CaliforniaLos AngelesCA 90095USA

To mitigate the impacts of land degradation and achieve sustainable development,several large-scale conservation programs including the Key Shelterbelt Construction Program,Natural Forest Conservation Program,and the Grain to Green Program have been formulated into action in China since the late 1970s and 1998,respectively[1].Recent satellite observations from 2000 to 2017 revealed a strikingly prominent greening in China due to these efforts[2].

关键词：全球气候模式区域气候模式近地表气温地球物理气温变化不均衡分布土壤水资源全球变暖

Implementing a New Snow Scheme in Simplified Simple Biosphere Model

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Advances in Atmospheric Sciences 2001年第3期18卷 335-354页

作者：孙菽芬薛永康 LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing Department of Geography University of Maryland USA

This paper describes a modified version of SSIB through implementing a new snow model (SAST) in Simplified Simple Biosphere Model SSIB for climate study and presents the evaluation results by testing the scheme based on the field data from Russia and France. The relevant equations in the scheme are given, which describe complicated interactive processes among air-vegetation-snow-soil continuum through mass and heat exchange. An efficient numerical scheme is developed to solve the nonlinear equations successfully. By using the field data from Russia and France, the function of the new scheme is evaluated. The numerical results from the scheme show good agreement with field data. It indicates that the scheme developed here is workable and can be extended for climate study. Key words Snow cover model (SAST) - SSIB - Implementing - Evaluation This work was supported by the foundation from China: 1)NSF Grant 49835010, 2) National key program G1998040900—Part 1, 3) NSF 40075019, 4) NSF 49823002.

关键词： Snow cover model (SAST) SSIB Implementing Evaluation

Risk factors associated with Salmonella in dairy cattle farms in Henan and Hubei provinces,China

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Animal Diseases 2023年第4期3卷 256-264页

作者： Jie Wang Xiaojie Zhu Yuxi Zhao yongkang xue Zhen Zhang Lei Yan Yingyu Chen Ian D.Robertson Aizhen Guo Joshua W.Aleri The State Key Laboratory of Agricultural Microbiology College of Veterinary MedicineHuazhong Agricultural UniversityWuhan 430070China School of Veterinary Medicine College of ScienceHealthEngineering and EducationMurdoch University90 South StreetMurdochWA 6150Australia Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology Huazhong Agricultural UniversityWuhan 430070China Henan Dairy Herd Improvement Center Zhengzhou 450046China Centre for Animal Production and Health Future Foods InstituteMurdoch University90 South StreetMurdochWA 6150Australia

A cross-sectional study was conducted to evaluate the risk factors associated with the Salmonella infection status of dairy herds in Henan and Hubei provinces,*** were assigned a Salmonella status based on the isolation of Salmonella from fecal samples obtained from adult lactating dairy *** on potential biosecurity risk factors was collected using a questionnaire template via a 15-min face-to-face interview with dairy cattle producers from May 2020 to March *** questionnaire consisted of 23 questions across two broad categories of potential biosecurity risk factors:farm and biosecurity managemental factors.A total of 48 farms were *** all(100%,48/48)of the surveyed farms,although sick animals were separated from healthy animals using fencing,there were no strict quarantine protocols for newly introduced *** species rearing was practiced in 35.4%(17/48)of the *** were removed more than once a day in 45.8%(22/48)of the farms,whereas the remainder(54.2%,26/48)only removed animal feces once a day.A total of 29.2%(14/48)of the farms were located<2 km from other livestock *** use of personal protective equipment was consistently performed on all farms,with a major-ity of the workers on most farms(81.3%,39/48)always disinfecting footwear before entering production areas.A significant association between Salmonella-positive status and the high frequency of the presence of wildlife(birds and rodents in sheds and feed storage places)was recorded(OR:11.9,95%Cl:1.7,84.1,p=0.013).Fortunately,no farms shared farm equipment with other *** study highlights the occurrence of wildlife as a risk factor for the presence of Salmonella in investigated dairy *** is a need to institute appropriate on-farm control measures for wild birds and rodents to control the potential spread of Salmonella in dairy production systems.

关键词： Cattle Management practices Risk factors Salmonella