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Decoding the inconsistency of six cropland maps in China

The Crop Journal 2024年第1期12卷 281-294页

作者： Yifeng Cui Ronggao Liu Zhichao Li Chao Zhang Xiao-Peng Song Jilin Yang Le Yu Mengxi Chen jinwei dong Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Department of Geographical Sciences University of MarylandCollege ParkMD 20740USA College of Grassland Science and Technology China Agricultural UniversityBeijing 100193China Ministry of Education Ecological Field Station for East Asian Migratory Birds Department of Earth System ScienceInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China Ministry of Education Ecological Field Station for East Asian Migratory Birds Beijing 100084China Tsinghua University(Department of Earth System Science)-Xi’an Institute of Surveying and Mapping Joint Research Center for Next-Generation Smart Mapping Beijing 100084China Institute of Remote Sensing and Geographic Information System Peking UniversityBeijing 100871China Department of Forest and Conservation Sciences University of British ColumbiaVancouverBCV6T 1Z4Canada

Accurate cropland information is critical for agricultural planning and production,especially in foodstressed countries like China.Although widely used medium-to-high-resolution satellite-based cropland maps have been developed from various remotely sensed data sources over the past few decades,considerable discrepancies exist among these products both in total area and in spatial distribution of croplands,impeding further applications of these datasets.The factors influencing their inconsistency are also unknown.In this study,we evaluated the consistency and accuracy of six cropland maps widely used in China in circa 2020,including three state-of-the-art 10-m products(i.e.,Google Dynamic World,ESRI Land Cover,and ESA WorldCover)and three 30-m ones(i.e.,GLC_FCS30,GlobeLand 30,and CLCD).We also investigated the effects of landscape fragmentation,climate,and agricultural management.Validation using a ground-truth sample revealed that the 10-m-resolution WorldCover provided the highest accuracy(92.3%).These maps collectively overestimated Chinese cropland area by up to 56%.Up to 37%of the land showed spatial inconsistency among the maps,concentrated mainly in mountainous regions and attributed to the varying accuracy of cropland maps,cropland fragmentation and management practices such as irrigation.Our work shed light on the promotion of future cropland mapping efforts,especially in highly inconsistent regions.

关键词： Consistency and accuracy 10-and 30 m Cropland mapping Agricultural management China

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A large forage gap in forage availability in traditional pastoral regions in China

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Fundamental Research 2023年第2期3卷 188-200页

作者： Tong Yang jinwei dong Lin Huang Yuzhe Li Huimin Yan Jun Zhai Jie Wang Zhenong Jin Geli Zhang College of Land Science and Technology China Agricultural UniversityBeijing 100193China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Satellite Environment Center Ministry of Ecology and Environment of the People's Republic of ChinaBeijing 100094China College of Grassland Science and Technology China Agricultural UniversityBeijing 100193China Department of Bioproducts and Biosystems Engineering University of MinnesotaSt.Paul 55108MNUnited States of America

Forage supply has been stressed due to the rapid increase in China's livestock consumption.However,the long-term dynamics of the relationships between forage demand and multi-sourced supply are not understood.Here,we examine the annual forage demand,or practical carrying capacity(PCC),and supply,or theoretical carrying capacity(TCC)from 2000 to 2019 in China.We construct a forage supply-demand index(FSDI)to represent the forage supply pressure using MODIS-derived net primary productivity products and provincial statistical datasets,and we consider two scenarios.First,natural grasslands are the sole source of forage.Second,natural grassland forage supply is supplemented with straw crops.We find an increase in PCC in northwestern China's major pastoral and agropastoral provincial regions,including Inner Mongolia,Gansu,Ningxia and Qinghai,at rate of 0.24-3.59 million sheep units(SU)a year.As the primary source of forage,the theoretical carrying capacity of natural grasslands(TCCgrass)expanded at a rate of 3 million SU/yr nationally.Crop straws fed 126.58 million SU nationally in 2019,which accounted for 11.3%of the total practical carrying capacity and alleviated the forage supply pressure by reducing FSDI by 26.56%.During 2000–2019,the theoretical carrying capacity of straw crops(TCCcrop)increased rapidly from 76.5 million SU to 126.6 million SU,which accounted for 10%-15%of the total forage supply at the national scale.We also discovered large carrying capacity gaps(TCCgap)in the northwestern pastoral provincial regions of Inner Mongolia,Xinjiang,Gansu,and some agricultural provinces such as Shandong and Henan,when we considered forage supply from both natural grasslands and straw crops.Our findings showed a large forage gap in the traditional pastoral regions,and we also discussed green fodder as a potential solution for balancing the supply of and demand for forage,which may shed light on crop and forage planning.

关键词： Forage supply-demand Natural grassland Crop straw Green fodder China Provincial

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Mapping paddy rice distribution using multi-temporal Landsat imagery in the Sanjiang Plain, northeast China

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Frontiers of Earth Science 2016年第1期10卷 49-62页

作者： Cui JIN Xiangming XIAO jinwei dong Yuanwei QIN Zongming WANG Department of Microbiology and Plant Biology Center for Spatial Analysis University of Oklahoma Norman OK 73019 USA Institute of Biodiversity Sciences Fudan University Shanghai 200433 China Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences Changchun 130102 China

Information of paddy rice distribution is essential for food production and methane emission calculation. Phenology-based algorithms have been uti- lized in the mapping of paddy rice fields by identifying the unique flooding and seedling transplanting phases using multi-temporal moderate resolution （500m to 1 km） images. In this study, we developed simple algorithms to identify paddy rice at a fine resolution at the regional scale using multi-temporal Landsat imagery. Sixteen Landsat images from 2010-2012 were used to generate the 30 m paddy rice map in the Sanjiang Plain, northeast China-one of the major paddy rice cultivation regions in China. Three vegetation indices, Normalized Difference Vegetation Index （NDVI）, Enhanced Vegetation Index （EVI）, and Land Surface Water Index （LSWI）, were used to identify rice fields during the flooding/transplanting and ripening phases. The user and producer accuracies of paddy rice on the resultant Landsat-based paddy rice map were 90% and 94%, respectively. The Landsat-based paddy rice map was an improvement over the paddy rice layer on the National Land Cover Dataset, which was generated through visual interpretation and digitalization on the fine-resolution images. The agricultural census data substantially underreported paddy rice area, raising serious concern about its use for studies on food security.

关键词： phenology flooding transplanting ripening,land use

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自愿披露客户信息影响了债券违约风险吗?

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南京审计大学学报 2024年第1期21卷 67-75页

作者：王生年董今威石河子大学经济与管理学院新疆石河子832000

以2010—2021年沪深A股上市公司发行的公司债为样本,实证检验了自愿披露客户信息对债券违约风险的影响。研究发现,自愿披露客户信息产生的额外风险加剧了债券违约风险,这种影响在高专有成本和高融资约束的企业中表现更为显著,但企业发... 详细信息

以2010—2021年沪深A股上市公司发行的公司债为样本,实证检验了自愿披露客户信息对债券违约风险的影响。研究发现,自愿披露客户信息产生的额外风险加剧了债券违约风险,这种影响在高专有成本和高融资约束的企业中表现更为显著,但企业发行的绿色债券并未受到影响。机制检验表明,经营风险增加和机构投资者持股降低是自愿披露客户信息影响债券违约风险的重要途径。研究表明,企业需要慎重考虑披露客户信息带来的风险,审慎制定信息披露策略。

关键词：客户信息披露债券违约风险风险效应专有成本融资约束机构投资者持股绿色债券

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Quantifying the response of surface urban heat island to urbanization using the annual temperature cycle model

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Geoscience Frontiers 2022年第1期13卷 478-487页

作者： Huidong Li Yuyu Zhou Gensuo Jia Kaiguang Zhao jinwei dong Department of Geological and Atmospheric Sciences Iowa State UniversityAmes 50011USA Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Ohio Agricultural Research and Development Center School of Environment and Natural ResourcesThe Ohio State UniversityWoosterOH 44691USA Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101

Urban heat island(UHI),driving by urbanization,plays an important role in urban sustainability under climate change.However,the quantification of UHI’s response to urbanization is still challenging due to the lack of robust and continuous temperature and urbanization datasets and reliable quantification methods.This study proposed a framework to quantify the response of surface UHI(SUHI)to urban expansion using the annual temperate cycle model.We built a continuous annual SUHI series at the buffer level from 2003 to 2018 in the Jing-Jin-Ji region of China using MODIS land surface temperature and imperviousness derived from Landsat.We then investigated the spatiotemporal dynamic of SUHI under urban expansion and examined the underlying mechanism.Spatially,the largest SUHI interannual variations occurred in suburban areas compared to the urban center and rural areas.Temporally,the increase in SUHI under urban expansion was more significant in daytime compare to nighttime.We found that the seasonal variation of SUHI was largely affected by the seasonal variations of vegetation in rural areas and the interannual variation was mainly attributed to urban expansion in urban areas.Additionally,urban greening led to the decrease in summer daytime SHUI in central urban areas.These findings deepen the understanding of the long-term spatiotemporal dynamic of UHI and the quantitative relationship between UHI and urban expansion,providing a scientific basis for prediction and mitigation of UHI.

关键词： Urban heat island Urbanization Spatiotemporal dynamics Annual temperature cycle model Diurnal temperature range

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Variations of Vegetation Phenology Extracted from Remote Sensing Data over the Tibetan Plateau Hinterland during 2000–2014

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Journal of Meteorological Research 2020年第4期34卷 786-797页

作者： Ya LIU Junbang WANG jinwei dong Shaoqiang WANG Hui YE Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural ResourcesChinese Academy of SciencesBeijing 100101 Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008

How vegetation phenology responds to climate change is a key to the understanding of the mechanisms driving historic and future changes in regional terrestrial ecosystem productivity. Based on the 250-m and 8-day moderate resolution imaging spectroradiometer(MODIS) normalized difference vegetation index(NDVI) data for 2000-2014 in the Three-River Source Region(TRSR) of Qinghai Province, China, i.e., the hinterland of the Tibetan Plateau, we extracted relevant vegetation phenological information(e.g., start, end, and length of growing season) and analyzed the changes in the TRSR vegetation in response to climate change. The results reveal that, under the increasingly warm and humid climate, the start of vegetation growing season(SOS) advanced 1.03 day yr-1 while the end of vegetation growing season(EOS) exhibited no significant changes, which led to extended growing season length. It is found that the SOS was greatly affected by the preceding winter precipitation, with progressively enhanced precipitation facilitating an earlier SOS. Moreover, as the variations of SOS and its trend depended strongly on topography, we estimated the elevation break-points for SOS. The lower the elevations were, the earlier the SOS started. In the areas below 3095-m elevation, the SOS delay changed rapidly with increasing elevation;whereas above that, the SOS changes were relatively minor. The SOS trend had three elevation break-points at 2660, 3880, and 5240 m.

关键词： Three-River Source Region(TRSR) start of vegetation growing season(SOS) spatiotemporal change elevation climate change China

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Cropland redistribution to marginal lands undermines environmental sustainability

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National Science Review 2022年第1期9卷 66-78页

作者： Wenhui Kuang Jiyuan Liu Hanqin Tian Hao Shi jinwei dong Changqing Song Xiaoyong Li Guoming Du Yali Hou Dengsheng Lu Wenfeng Chi Tao Pan Shuwen Zhang Rafiq Hamdi Zherui Yin Huimin Yan Changzhen Yan Shixin Wu Rendong Li Jiuchun Yang Yinyin Dou Wenbin Wu Liqiao Liang Bao Xiang Shiqi Yang Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences School of Geographical Sciences Fujian Normal University Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences International Center for Climate and Global Change Research School of Forestry and Wildlife Sciences Auburn University School of Geography and Tourism Qufu Normal University Hubei Province’s Key Laboratory for Environment & Disaster Monitoring and Evaluation Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Royal Meteorological Institute of Belgium Key Laboratory for Resources Use & Environmental Remediation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences School of Resources and Environmental Economics Inner Mongolia University of Finance and Economics State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences School of Public Administration and Law Northeast Agricultural University Institute of Ecology Chinese Research Academy of Environmental Sciences Faculty of Geographical Science Beijing Normal University College of Environment and Planning Henan University Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences

Cropland redistribution to marginal land has been reported worldwide;however,the resulting impacts on environmental sustainability have not been investigated sufficiently.Here we investigated the environmental impacts of cropland redistribution in China.As a result of urbanization-induced loss of high-quality croplands in south China(～8.5 t ha),croplands expanded to marginal lands in northeast(～4.5 t ha) and northwest China(～2.9 t ha) during 1990-2015 to pursue food security.However,the reclamation in these low-yield and ecologically vulnerable zones considerably undermined local environmental sustainability,for example increasing wind erosion(+3.47%),irrigation water consumption(+34.42%),fertilizer use(+20.02%) and decreasing natural habitats(-3.11%).Forecasts show that further reclamation in marginal lands per current policies would exacerbate environmental costs by 2050.The future cropland security risk will be remarkably intensified because of the conflict between food production and environmental sustainability.Our research suggests that globally emerging reclamation of marginal lands should be restricted and crop yield boost should be encouraged for both food security and environmental benefits.

关键词： cropland redistribution environmental sustainability marginal lands wind erosion irrigation water consumption

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The relationships between urban-rural temperature difference and vegetation in eight cities of the Great Plains

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Frontiers of Earth Science 2019年第2期13卷 290-302页

作者： Yaoping CUI Xiangming XIAO Russell B DOUGHTY Yaochen QIN Sujie LIU Nan LI Guosong ZHAO jinwei dong Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Henan UniversityKaifeng 475004China Department of Microbiology and Plant Biology Center for Spatial AnalysisUniversity of OklahomaNormanOK 73019USA Ministry of Education Key Laboratory of Biodiversity Science and Ecological Engineering Institute of Biodiversity ScienceFudan UniversityShanghai 200438China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

Interpreting the relationship between urban heat island (UHI) and urban vegetation is a basis for understanding the impacts of underlying surfaces on UHL The calculation of UHI intensity (UHII) requires observations from paired stations in both urban and rural areas.Due to the limited number of paired meteorological stations,many studies have used remotely sensed land surface temperature,but these time-series land surface temperature data are often heavily affected by cloud cover and other factors.These factors,together with the algorithm for inversion of land surface temperature,lead to accuracy problems in detecting the UHII,especially in cities with weak UHII.Based on meteorological observations from the Oklahoma Mesonet,a world-class network,we quantified the UHII and trends in eight cities of the Great Plains,USA,where data from at least one pair of urban and rural meteorological stations were available.We examined the changes and variability in urban temperature,UHII,vegetation condition (as measured by enhanced vegetation index,EVI),and evapotranspiration (ET).We found that both UHI and urban cold islands (UCI) occurred among the eight cities during 2000-2014 (as measured by impervious surface area).Unlike what is generally considered,UHII in only three cities significantly decreased as EVI and ET increased (p < 0.1),indicating that the UHI or UCI cannot be completely explained simply from the perspective of the underlying surface.Increased vegetative cover (signaled by EVI) can increase ET,and thereby effectively mitigate the UHI.Each study station clearly showed that the underlying surface or vegetation affects urban-rural temperature,and that these factors should be considered during analysis of the UHI effect over time.

关键词： urbanization evapotranspiration urban cold island background climate air temperature

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Continued Increases of Gross Primary Production in Urban Areas during 2000-2016

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Journal of Remote Sensing 2022年第1期2022卷 98-111页

作者： Yaoping Cui Xiangming Xiao jinwei dong Yao Zhang Yuanwei Qin Russell BDoughty Xiaocui Wu Xiaoyan Liu Joanna Joiner Berrien Moore III Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University) Ministry of EducationKaifeng 475001China School of Geography And Environmental Science Henan UniversityKaifeng 475004China Department of Microbiology and Plant Biology Center for Earth Observation and ModelingUniversity of OklahomaNormanOKUSA Institute of Geographical Sciences and Resources Chinese Academy of SciencesBeijing 100101China College of Atmospheric and Geographic Sciences University of OklahomaOK 73019USA Agroecosystem Sustainability Center Institute for SustainabilityEnergyAnd EnvironmentUniversity of Illinois Urbana-ChampaignUrbanaIL 61801USA NASA Goddard Space Flight Center GreenbeltMD 20771USA

Urbanization affects vegetation within city administrative boundary and nearby rural areas.Gross primary production(GPP)of vegetation in global urban areas is one of important metrics for assessing the impacts of urbanization on terrestrial ecosystems.To date,very limited data and information on the spatial-temporal dynamics of GPP in the global urban areas are available.In this study,we reported the spatial distribution and temporal dynamics of annual GPP during 2000–2016 from 8,182 gridcells(0.5°by 0.5°latitude and longitude)that have various proportion of urban areas.Approximately 79.3%of these urban gridcells had increasing trends of annual GPP during 2000-2016.As urban area proportion(%)within individual urban gridcells increased,the means of annual GPP trends also increased.Our results suggested that for those urban gridcells,the negative effect of urban expansion(often measured by impervious surfaces)on GPP was to large degree compensated by increased vegetation within the gridcells,mostly driven by urban management and local climate and environment.Our findings on the continued increases of annual GPP in most of urban gridcells shed new insight on the importance of urban areas on terrestrial carbon cycle and the potential of urban management and local climate and environment on improving vegetation in urban areas.

关键词： Urbanization urban continued

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English Speech Recognition and Multidimensional Pronunciation Evaluation

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教育研究前沿（中英文版） 2020年第3期10卷 184-188页

作者： jinwei dong Shaohui Li School of English Education Guangdong University of Foreign StudiesGuangzhou 510006China

As one of the four major skills in English learning,speaking is an important part in English learning which getting more and more attention.The study set out to improve the accuracy of speech recognition by applying speech recognition technology to the evaluation of English pronunciation.On this basis,the study attempts to improve computer speech evaluation methods.This model employs indexes such as intonation,speech rate,rhythm and intonation,using multi-dimensional indicators as evaluation criteria to establish a more comprehensive and objective English speech evaluation model.English learners can use the evaluation systems to guide their self-study,and the system can have a profound influence on the practice of teaching spoken English.

关键词： Spoken English Speech Recognition Pronunciation Evaluation

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