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The influence of urban three-dimensional structure and building greenhouse effect on local radiation flux

Science China Earth Sciences 2021年第11期64卷 1934-1948页

作者： Renhua ZHANG Wenhui KUANG Shiqi YANG Zhaoliang LI Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Resources and Environment Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural SciencesBeijing 100081China

Accurate measurements of the three-dimensional structure characteristics of urban buildings and their greenhouse effect are important for evaluating the impact of urbanization on the radiation energy budget and research on the urban heat island(UHI)*** decrease in evapotranspiration or the increase in sensible heat caused by urbanization is considered to be the main cause of the UHI effect,but little is known about the influence of the main factor“net radiant flux”of the urban surface heat *** this study,experimental observation and quantitative model simulation were used to find that with the increase of building surface area after urbanization,the direct solar radiation flux and net radiation flux on building surface areas changed *** order to accurately quantify the relationship between the positive and negative effects,this study puts forward the equivalent calculation principle of“aggregation element”,which is composed of a building’s sunny face and its shadow face,and the algorithm of the contribution of the area to thermal *** research clarifies the greenhouse effect of a building with walls of glass *** shows that when the difference between absorption rates of a concrete wall and grass is−0.21,the cooling effect is *** the case of concrete walls with glass windows,the difference between absorption rates of a building wall and grass is−0.11,which is also a cooling *** greenhouse effect value of a building with glass windows reduces the cooling effect value to 56%of the effect of a building with concrete *** simulation of changes in net radiant flux and flux density shows that the greenhouse effect of a 5-story building with windows yields 15.5%less cooling effect than one with concrete walls,and a 30-story building with windows reduces the cooling effect by 23.0%.The simulation results confirmed that the difference in the equivalent absorption rate of the aggregation element is the“director”of

关键词： Aggregation element algorithm Greenhouse effect of buildings with windows Net radiation flux Direct solar radiation flux Architectural shadow

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Damage evaluation of soybean chilling injury based on Google Earth Engine(GEE)and crop modelling

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Journal of Geographical Sciences 2020年第8期30卷 1249-1265页

作者： CAO Juan ZHANG Zhao ZHANG Liangliang LUO Yuchuan LI Ziyue TAO Fulu State Key Laboratory of Earth Surface Processes and Resource Ecology/MEM&MoE Key Laboratory of Environmental Change and Natural Hazards Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Frequent chilling injury has serious impacts on national food security and in northeastern China heavily affects grain *** and accurate measures are desirable for assessing associated large-scale impacts and are prerequisites to disaster ***,we propose a novel means to efficiently assess the impacts of chilling injury on *** chilling injury events were diagnosed in 1989,1995,2003,2009,and 2018 in Oroqen *** total,512 combinations scenarios were established using the localized CROPGRO-Soybean ***,we determined the maximum wide dynamic vegetation index(WDRVI)and corresponding date of critical windows of the early and late growing seasons using the GEE(Google Earth Engine)platform,then constructed 1600 cold vulnerability models on CDD(Cold Degree Days),the simulated LAI(Leaf Area Index)and yields from the CROPGRO-Soybean ***,we calculated pixel yields losses according to the corresponding vulnerability *** findings show that simulated historical yield losses in 1989,1995,2003 and 2009 were measured at 9.6%,29.8%,50.5%,and 15.7%,respectively,closely(all errors are within one standard deviation)reflecting actual losses(6.4%,39.2%,47.7%,and 13.2%,respectively).The above proposed method was applied to evaluate the yield loss for 2018 at the pixel ***,a sentinel-2A image was used for 10-m high precision yield mapping,and the estimated losses were found to characterize the actual yield losses from 2018 cold *** results highlight that the proposed method can efficiently and accurately assess the effects of chilling injury on soybean crops.

关键词： chilling injury Google Earth Engine(GEE) CROPGRO-Soybean soybean yield loss cold degree days(CDD)

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How farmers’non-agricultural employment affects rural land circulation in China?

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Journal of Geographical Sciences 2020年第3期30卷 378-400页

作者： WANG Jiayue XIN Liangjie WANG Yahui Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China School of Geographical Science Southwest UniversityChongqing 400715China

To clarify the impact of non-agricultural employment on rural land circulation in China,we built logit models using the Chinese Household Income Project 2013 dataset,which includes 18,948 household samples over 15 provinces,126 cities and 234 counties of China in *** use the proportion of non-agricultural income,the proportion of non-agricultural laborers and non-agricultural fixed operating assets to reflect the degree of the households’dependence on agriculture,the degree of the households’laborers committed to non-agricultural employment and the stability of non-agricultural employment,*** results show that the stability of non-agricultural employment is an important reason for farmers to transfer out their land,and an increase in non-agricultural income is the fundamental *** proportion of non-agricultural assets has the greatest impact on the decision to transfer land,followed by the proportion of non-agricultural *** unit increase in the non-agricultural income ratio has a stronger effect on the transfer-out decision than it does on the transfer-in decision,which is a 0.09 increase of the probability of transfer-out the land and a 0.07 decrease of the probability of transfer-in the *** terms of regional differences,when considering the impact of non-agricultural employment on the land transfer-out decision,the impacts of non-agricultural income and labor force are the greatest in the Central *** impact of non-agricultural assets is the greatest in the Eastern *** the Eastern region,the decision to transfer out land is mainly affected by non-agricultural assets and the non-agricultural labor force,and the decision to transfer in land is mainly affected by non-agricultural *** the Central and Western regions,the decision to transfer out land is mainly affected by non-agricultural assets,non-agricultural income and the non-agricultural labor force,in that *** decision to transfer in land in the Central

关键词： farmers’non-agricultural employment rural land circulation moderate scale management China CHIP2013 dataset

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Intensified risk to ecosystem productivity under climate change in the arid/humid transition zone in northern China

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Journal of Geographical Sciences 2021年第9期31卷 1261-1282页

作者： YIN Yunhe DENG Haoyu MA Danyang WU Shaohong Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Henan Province Development and Reform Commission Zhengzhou 450018China University of Chinese Academy of Sciences Beijing 100049China

Assessing the climate change risk faced by the ecosystems in the arid/humid transition zone(AHTZ)in northern China holds scientific significance to climate change *** simulated the net primary productivity(NPP)for four representative concentration pathways(RCPs)using an improved Lund-Potsdam-Jena *** a method was established based on the NPP to identify the climate change risk *** the midterm period(2041–2070)to the long-term period(2071–2099),the risks indicated by the negative anomaly and the downward trend of the NPP gradually extended and *** higher the scenario emissions,the more serious the *** particular,under the RCP8.5 scenario,during 2071–2099,the total risk area would be 81.85%,that of the high-risk area would reach 54.71%.In this high-risk area,the NPP anomaly would reach–96.00±46.95 gC·m-2·a-1,and the rate of change of the NPP would reach–3.56±3.40 gC·m-2·*** eastern plain of the AHTZ and the eastern grasslands of Inner Mongolia are expected to become the main risk concentration *** results indicated that the management of future climate change risks requires the consideration of the synergistic effects of warming and intensified drying on the ecosystem.

关键词： climate change risk assessment arid/humid transition zone NPP ecosystem

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Flash flood type identification and simulation based on flash flood behavior indices in China

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Science China Earth Sciences 2021年第7期64卷 1140-1154页

作者： Xiaoyan ZHAI Liang GUO Yongyong ZHANG State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Research Center on Flood and Drought Disaster ReductionChina Institute of Water Resources and Hydropower ResearchBeijing 100038China Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Flash floods present significant heterogeneity over both space and time due to diverse topographic,geomorphologic,and hydro-meteorological conditions of *** identification and simulation of typical flash flood types are of great significance for the mitigation of flash flood disasters at the national *** flood peak indices and dynamic indices were adopted to characterize the behavioral variability of flash *** typical flash flood types and corresponding behavior indices were identified and simulated using statistical analysis(i.e.,principal component analysis,dynamic K-means clustering,and analysis of similarity)and hydrological modelling(i.e.,HEC and XAJ models).There were 177 flash flood events at the hourly scale being selected for case study from eight catchments with various climatic and geographic *** showed that all the flash flood events were clustered into three types(named Types 1,2,and 3).Type 1 was characterized by low peak flow intensity,early flood peak occurrence time,and thin flood process with short *** 2 was characterized by low peak flow intensity,late flood peak occurrence time,and flat flood process with long *** 3 was characterized by high peak flow intensity and late flood peak occurrence *** flood types showed high consistency with their influencing factors(e.g.,catchment forest ratio and drainage area,occurrence time and magnitude of maximum storm intensity,and concentration of a storm event).The simulation performances were basically the same for HEC and XAJ *** for flash flood event simulations,the average relative error varied from 23.25%to 27.98%,from 11.95%to 18.19%,and from 8.30%to18.25%for Types 1,2 and 3,*** average Nash-Sutcliffe efficiency coefficient varied from 0.39 to 0.54,from 0.76 to 0.85,and from 0.86 to 0.91,*** for the six flash flood behavior indices simulations,the average relative rootmean-square error(RMSEr)varie

关键词： Flood similarity Flood behavior Statistical analysis HEC and XAJ models Humid and semi-humid catchments

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The 5.5 cal ka BP climate event, population growth, circumscription and the emergence of the earliest complex societies in China

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Science China Earth Sciences 2018年第2期61卷 134-148页

作者： WU WenXiang ZHENG HongBo HOU Mei GE QuanSheng Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Research Center for Earth System Science Yunnan University Kunming 650091 China University of Chinese Academy of Sciences Beijing 100049 China

The emergence of complex society is a milestone in the history of human society evolution. China is one of the few regions in the world where the earliest complex society appeared; however, its driving mechanisms remain unresolved. On the base of available evidence from both archaeology and Holocene climate, in combination with agency theory, this study attempts to address the driving mechanisms for the simultaneous emergence of complex societies in multiple areas of China around 5.5 cal ka BP. It is hypothesized that three factors, including climate change, population growth, and circumscription, jointly act and cause regional population-resource imbalance and trigger inter-group conflicts and wars. Such competitions provide the opportunity for some power-pursuing agents to break the restriction of social leveling mechanism and to become the centralized decision-making leaders, which further lead to the emergence of incipient large-scale complex societies. Increase in extreme climate events during 6.0–5.0 cal ka BP cooling period causes frequent occurrence of resource stress and increase in the frequency of inter-group competitions, which creates conditions for the legitimation, institutionalization, and persistence of centralized leadership, and finally leads to the formation of persistent institutionalized inequity. Our research result can explain not only the process and mechanism of complex society formation, but also two phenomena which cannot be reasonably explained by previous theories, that are, why the earliest complex societies in China emerge around 5.5 cal ka BP, and why they appear simultaneously in multiple regions.

关键词： 5.5 cal ka BP climate event Population growth Circumscription Complex society Driving mechanisms

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Quantification of human and climate contributions to multi-dimensional hydrological alterations:A case study in the Upper Minjiang River,China

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Journal of Geographical Sciences 2021年第8期31卷 1102-1122页

作者： ZHANG Yuhang YE Aizhong YOU Jinjun JING Xiangyang State Key Laboratory of Earth Surface Processes and Resource Ecology Institute of Land Surface System and Sustainable DevelopmentFaculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China POWERCHINA Chengdu Engineering Corporation Limited Chengdu 611130China

Dual factors of climate and human on the hydrological process are reflected not only in changes in the spatiotemporal distribution of water resource amounts but also in the various characteristics of river flow regimes. Isolating and quantifying their contributions to these hydrological alterations helps us to comprehensively understand the response mechanism and patterns of hydrological process to the two kinds of factors. Here we develop a general framework using hydrological model and 33 indicators to describe hydrological process and quantify the impact from climate and human. And we select the Upper Minjiang River(UMR) as a case to explore its feasibility. The results indicate that our approach successfully recognizes the characteristics of river flow regimes in different scenarios and quantitatively separates the climate and human contributions to multi-dimensional hydrological alterations. Among these indicators, 26 of 33 indicators decrease over the past half-century(1961–2012) in the UMR, with change rates ranging from 1.3% to 33.2%, and the human impacts are the dominant factor affecting hydrological processes, with an average relative contribution rate of 58.6%. Climate change causes an increase in most indicators, with an average relative contribution rate of 41.4%. Specifically, changes in precipitation and reservoir operation may play a considerable role in inducing these alterations. The findings in this study help us better understand the response mechanism of hydrological process under changing environment and is conducive to climate change adaptation, water resource planning and ecological construction.

关键词： hydrological alterations Minjiang River Basin quantitative assessment climate change direct human impacts

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Spatio-temporal variations in ecological spaces and their ecological carrying status in China's mega-urban agglomerations

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Journal of Geographical Sciences 2022年第9期32卷 1683-1704页

作者： WANG Shihao HUANG Lin XU Xinliang LI Jiahui State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China University of Chinese Academy of Sciences Beijing100049China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China

The rapid expansion of China’s urban agglomerations in recent decades has resulted in over-occupied ecological spaces and increased ecological pressure that are restricting healthy regional *** paper examines the structure and characteristics of distribution of“production-living-ecological”spaces in five mega-urban agglomerations in China:Beijing-Tianjin-Hebei(BTH),the Yangtze River Delta(YRD),Guangdong-Hong Kong-Macao Greater Bay Area(GBA),Chengdu-Chongqing(CY),and the middle reaches of the Yangtze River(MYR).We analyze spatial and temporal variations in the ecological spaces and factors influencing them from 1990 to 2020,and examine the comprehensive ecological carrying capacity and status of ecological spaces in the past 30 years based on the available water resources,regulation of water and air quality,and leisure and *** results show the following:(1)Urban agglomerations in different stages of formation and development represent varying area ratios of“ecological-production-living”*** modes of expansion and evolution of the living spaces are dominated by multi-center combinations as well as the spatial structure of ecological spaces,including barrier,compact,discrete,and fully enveloping spaces.(2)From 1990 to 2020,the area occupied by living spaces in urban agglomerations continued to increase significantly while that of spaces for ecological production *** in the GBA,ecological spaces have exhibited a trend of increase in area,especially in the past 10 *** area ratios and spatio-temporal variations in the“production-living-ecological”spaces indicate that the main functions of production and ecological spaces in mega-urban agglomerations have shifted from supply to regulation and culture,and reflect the transition from rapid urbanization to sustainable urbanization in China.(3)The comprehensive ecological carrying capacities of 78.6%,73.1%,54.5%,56.3%,and 25.8%of cities in BTH,YRD,GBA,CY and MYR are severely ove

关键词： mega-urban agglomerations “production-living-ecological”spaces ecological spaces ecological carrying capacity spatial and temporal variations

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Pedotransfer Functions for Estimating Soil Bulk Density:A Case Study in the Three-River Headwater Region of Qinghai Province,China

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Pedosphere 2016年第3期26卷 362-373页

作者： YI Xiangsheng LI Guosheng YIN Yanyu Agriculture Resource Monitoring Station Chinese Academy of Agricultural Engineering Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of Sciences Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Bulk density(BD) is an important soil physical property and has significant effect on soil water conservation function. Indirect methods, which are called pedotransfer functions(PTFs), have replaced direct measurement and can acquire the missing data of BD during routine soil surveys. In this study, multiple linear regression(MLR) and artificial neuron network(ANN) methods were used to develop PTFs for predicting BD from soil organic carbon(OC), texture and depth in the Three-River Headwater region of Qinghai Province, China. The performances of the developed PTFs were compared with 14 published PTFs using four indexes, the mean error(ME), standard deviation error(SDE), root mean squared error(RMSE) and coefficient of determination(R^2). Results showed that the performances of published PTFs developed using exponential regression were better than those developed using linear regression from OC. Alexander(1980)-B, Alexander(1980)-A and Manrique and Jones(1991)-B PTFs, which had good predictions, could be applied for the soils in the study area. The PTFs developed using MLR(MLR-PTFs) and ANN(ANN-PTFs) had better soil BD predictions than most of published PTFs. The ANN-PTFs had better performances than the MLR-PTFs and their performances could be improved when soil texture and depth were added as predictor variables. The idea of developing PTFs for predicting soil BD in the study area could provide reference for other areas and the results could lay foundation for the estimation of soil water retention and carbon pool.

关键词： alpine soil artificial neural network multiple linear regression organic carbon soil depth soil texture

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Evaluating the reliability of global historical land use scenarios for forest data in China

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Journal of Geographical Sciences 2020年第7期30卷 1083-1094页

作者： YANG Fan HE Fanneng LI Meijiao LI Shicheng Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China School of Public Administration China University of GeosciencesWuhan 430074China

Global historical land use scenarios are widely used to simulate the climatic and ecological effects of changes in land cover;however,reliability evaluation of these scenarios for data on China’s forests is *** using a historical document-derived Chinese forest dataset(CHFD)for the years 1700–2000,we evaluated the reliability of data on forests in China over three global scenarios-SAGE(Center for Sustainability and the Global Environment),PJ(Pongratz Julia),and KK10(Kaplan and Krumhardt 2010)-through trend-related,quantitative,and spatial *** results show the following:(1)Although the area occupied by forests in China in the SAGE,PJ,KK10,and CHFD datasets decreased over the past 300 years,there were large differences between global scenarios and *** area occupied by forests in China in the SAGE scenario for 1700–1990 was 20%–40%more than that according to CHFD,and that occupied by forests in the KK10 from 1700 to 1850 was 32%–46%greater than that in *** difference between the PJ and CHFD was lower than 20%for most years.(2)Large differences were detected at the provincial and grid cell scales,where the PJ scenario was closer to CHFD in terms of total forested *** with large differences in terms of trend and quantity were 84%and 92%of all provinces,*** cells with relative differences greater than 70%accounted for 60%–80%of all grids.(3)These global historical land use scenarios do not accurately reveal the spatiotemporal pattern of Chinese forests due to differences in the data sources,methods of reconstruction,and spatial scales.

关键词： land use historical forest natural vegetation global scenarios reliability evaluation China

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