检索结果-南通市图书馆

Nonlinear relationship between urban form and transport CO_(2)emissions:Evidence from Chinese cities based on machine learning

引用

Journal of geographical Sciences 2024年第8期34卷 1558-1588页

作者： LI Linna DENG Zilin HUANG Xiaoyan Faculty of geographical Science Beijing Normal UniversityBeijing 100875China Northwest Land and Resources research Center Global Regional and Urban Research InstituteShaanxi Normal UniversityXi'an 710119China

Reducing carbon emissions from the transport sector is essential for realizing the carbon neutrality goal in *** substantial studies on the influence of urban form on transport cO_(2)emissions,most of them have treated the effects as a linear process,and few have studied their nonlinear *** research focused on 274 Chinese cities in 2019 and applied the gradient-boosting decision tree(GBDT)model to investigate the nonlinear effects of four aspects of urban form,including compactness,complexity,scale,and fragmentation,on urban transport CO_(2)*** was found that urban form contributed 20.48%to per capita transport CO_(2)emissions(PTCEs),which is less than the contribution of socioeconomic development but more than that of transport *** contribution of urban form to total transport CO_(2)emissions(TCEs)was the lowest,at 14.3%.In particular,the effect of compactness on TCEs was negative within a threshold,while its effect on PTCEs showed an inverted U-shaped *** effect of complexity on PTCEs was positive,and its effect on TCEs was *** effect of scale on TCEs and PTCEs was positive within a threshold and negative beyond that *** effect of fragmentation on TCEs was also nonlinear,while its effect on PTCEs was positively *** results show the complex effects of the urban form on transport CO_(2)***,strategies for optimizing urban form and reducing urban transport carbon emissions are recommended for the future.

关键词： urban form transport CO,emissions nonlinear effect sustainable transport gradient-boosting decision treemodel

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

15N tracers and microbial analyses reveal in situ N2O sources in contrasting water regimes of a drained peatland forest

引用

Pedosphere 2024年第4期34卷 749-758页

作者： Mohit MASTA Mikk ESPENBERG Laura KUUSEMETS Jaan P?RN Sandeep THAYAMKOTTU Holar SEPP Kalle KIRSIM?E Fotis SGOURIDIS Kuno KASAK Kaido SOOSAAR ülo MANDER institute of Ecology and Earth Sciences University of Tartu School of geographical Sciences University of Bristol University Road

Managed peatlands are a significant source of nitrous oxide（N2O）, a powerful greenhouse gas and stratospheric ozone depleter. Due to the complexity and diversity of microbial N2O processes, different methods such as tracer, isotopomer, and microbiological technologies are required to understand these processes. The combined application of different methods helps to precisely estimate these processes, which is crucial for the future management of drained peatlands, and to mitigate soil degradation and negative atmospheric impact. In this study, we investigated N2O sources by combining tracer, isotopomer,and microbial analysis in a drained peatland forest under flooded and drained treatments. On average, the nitrification genes showed higher abundances in the drained treatment, and the denitrification genes showed higher abundances in the flooded treatment. This is consistent with the underlying chemistry,as nitrification requires oxygen while denitrification is anaerobic. We observed significant differences in labelled N2O fluxes between the drained and flooded treatments. The emissions of N2O from the flooded treatment were nearly negligible, whereas the N2O evolved from the nitrogen -15(15N)-labelled ammonium(15NH4+) in the drained treatment peaked at 147 μg15N m-2h-1. This initially suggested nitrification as the driving mechanism behind N2O fluxes in drained peatlands, but based on the genetic data, isotopic analysis, and N2O mass enrichment, we conclude that hybrid N2O formation involving ammonia oxidation was the main source of N2O emissions in the drained treatment. Based on the15N-labelled nitrate(15NO3-) tracer addition and gene copy numbers, the low N2O emissions in the flooded treatment came possibly from complete denitrification producing inert dinitrogen. At atomic level, we observed selective enrichment of mass 45 of N2O molecule under15NH4+amendment in the drained treatment and enrichment of both masses 45 and 46under15NO3-amendment in the flooded trea

关键词： denitrification field experiment isotopes nitrification nitrous oxide qPCR

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Housing vacancy identification in shrinking cities based on multi-source data:A case study of Fushun city in Northeast China

引用

Journal of geographical Sciences 2024年第1期34卷 89-111页

作者： SUN Hongri ZHOU Guolei LIU Yanjun FU Hui JIN Yu School of geographical Sciences Northeast Normal UniversityChangchun 130024China Northeast institute of Geography and Agroecology CASChangchun 130102China

Urban shrinkage has attracted the attention of many geographers and urban planners in recent ***,there are fewer studies on vacant housing in shrinking ***,this study combines multi-source remote sensing images and urban building data to assess the spatiotemporal variation patterns of housing vacancy in a typical shrinking city in *** following points were obtained:(1)We developed an evaluation model to identify vacant residential buildings in shrinking cities by removing the contribution of nighttime lights from roads and non-residential buildings;(2)The residential building vacancy rate in Fushun city significantly increased from 2013 to 2020,resulting in a significant high-value clustering *** impact of urban shrinkage on vacant residential buildings was higher than that on vacant non-residential buildings;(3)The World Pop population data demonstrated consistent spatial distribution and trend of population change in Fushun with the residential building vacancy rate results,suggesting good reliability of the constructed evaluation model in this *** housing vacancies can help the local government to raise awareness of the housing vacancy problem in shrinking cities and to propose reasonable renewal strategies.

关键词： housing vacancy residential building vacancy urban shrinkage VIIRS

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Grain size and surface micro-texture characteristics and their paleoenvironmental significance of Holocene sediment in southern margin of the Gurbantunggut Desert,China

引用

Journal of Arid Land 2024年第5期16卷 632-653页

作者： MA Yunqiang LI Zhizhong TAN Dianjia ZOU Xiaojun TAO Tonglian School of geographical Sciences Fujian Normal UniversityFuzhou 350117China Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350117China institute of Geography Fujian Normal UniversityFuzhou 350117China

The southern margin of the Gurbantunggut Desert,China,is characterized by alternating layers of aeolian and alluvial *** the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces,as well as the provenance of ***,there are relatively few investigations on the characteristics of such sediment at *** this study,we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut *** on the optically stimulated luminescence(OSL)dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture,we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene,as well as the provenance of *** results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand,interdune sand,muddy desert surface soil,and riverbed *** frequency curves were unimodal or bimodal,and cumulative probability curves were two-segment or three-segment,mainly composed of suspension load and saltation *** quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces,with short transportation distance and time,and sedimentary environment was relatively *** Holocene,southern margin of the desert primarily featured braided river deposits,and during intermittent period of river activity,there were also aeolian deposits such as sand sheet deposits,stabilized dune deposits,and mobile dune *** provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant,with the debris of the Tianshan Mountains being the primary *** sand is mainly near-source recharge,

关键词： aeolian-alluvial deposition grain size surface micro-texture sedimentary environment Holocene

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

EvolveKG:a general framework to learn evolving knowledge graphs

引用

Frontiers of Computer Science 2024年第3期18卷 43-59页

作者： Jiaqi LIU Zhiwen YU Bin GUO Cheng DENG Luoyi FU Xinbing WANG Chenghu ZHOU School of Computer Science Northwestern Polytechnical UniversityXi’an 710129China Department of Computer Science Shanghai Jiao Tong UniversityShanghai 200240China institute of geographical Science and Natural Resources research Chinese Academy of SciencesBejjing 100864China

A great many practical applications have observed knowledge evolution,i.e.,continuous born of new knowledge,with its formation influenced by the structure of historical *** observation gives rise to evolving knowledge graphs whose structure temporally grows over ***,both the modal characterization and the algorithmic implementation of evolving knowledge graphs remain *** this end,we propose EvolveKG–a general framework that enables algorithms in the static knowledge graphs to learn the evolving *** quantifies the influence of a historical fact on a current one,called the effectiveness of the fact,and makes knowledge prediction by leveraging all the cross-time knowledge *** novelty of EvolveKG lies in Derivative Graph–a weighted snapshot of evolution at a certain ***,each weight quantifies knowledge effectiveness through a temporarily decaying function of consistency and attenuation,two proposed factors depicting whether or not the effectiveness of a fact fades away with ***,considering both knowledge creation and loss,we obtain higher prediction accuracy when the effectiveness of all the facts increases with time or remains *** four real datasets,the superiority of EvolveKG is confirmed in prediction accuracy.

关键词： knowledge graph evolution modal characterization algorithmic implementation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

How Does Urban Shrinkage Affect Land Use Efficiency?A Case Study of Shrinking Cities in Northeast China

引用

Chinese geographical Science 2024年第1期34卷 34-51页

作者： XIE Mingke FENG Zhangxian SONG Yang GUAN Haoming WANG Shijun School of geographical Sciences Northeast Normal UniversityChangchun130024China

The effect of urban shrinkage has gradually become a new ***,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these *** the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting *** quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply *** results show that urban shrinkage will affect LUE through a direct path and indirect *** the direct path,urban shrinkage leads to an improvement in *** the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this *** important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.

关键词： urban shrinkage land use efficiency Super-SBM-Undesirable model Structural Equation Model(SEM) Northeast China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Coordination Mechanism and Empirical research on Marine Science Technology Innovation and Marine Eco-civilization:A Case Study of Coastal Areas of China

引用

Chinese geographical Science 2024年第3期34卷 468-486页

作者： CHEN Xiaolong LIANG Chenlu DI Qianbin School of geographical Science Liaoning Normal UniversityDalian 116029China institute of Marine Sustainable Development Liaoning Normal UniversityDalian 116029China

Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology ***,the coordinated development of the two is of great significance to the marine economy sustainable development in China’s coastal *** the basis of clarifying the connotations of marine science technology innovation and marine eco-civilization in China’s coastal areas from 2006 to 2019,the mechanism for their coordinated development was analysed.A comprehensive indicator system based on the connotation of the two was constructed,and the coordinated development relationship was empirically tested using the coupled coordination model and the panel vector autoregressive(PVAR)*** results show that:1)the level of China’s coastal marine science technology innovation continues to improve,gradually forming the core of the development of marine science technology innovation in the north,east and south of Shandong,Shanghai and Guangdong;the level of marine eco-civilization development fluctuating upward trend,showing obvious spatial differentiation characteristics.2)The degree of coordination of marine science technology innovation and marine eco-civilization is growing over *** is no causal relationship between marine science technology innovation and marine eco-civilization in the northern marine economic circle,but there is a two-way causal relationship between the two in the eastern and southern marine economic circles.3)Marine eco-civilization shows a significant positive and continuous impact on marine science technology innovation,and marine science technology innovation shows a long-term,continuous,fluctuating,and lagging impact on marine *** overall role of marine eco-civilization on marine science technology innovation is dominant,and there are significant differences in the impact effects of the two major marine economic circles.

关键词： marine science technology innovation marine eco-civilization coordinated development coastal areas of China

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The interaction between temperature and precipitation on the potential distribution range of Betula ermanii in the alpine treeline ecotone on the Changbai Mountain

引用

Forest Ecosystems 2024年第1期11卷 42-51页

作者： Yu Cong Yongfeng Gu Wen J.Wang Lei Wang Zhenshan Xue Yingyi Chen Yinghua Jin Jiawei Xu Mai-He Li Hong S.He Ming Jiang Northeast institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China Key Laboratory of geographical Processes and Ecological Security in Changbai Mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun 130024China School of Natural Resources University of MissouriColumbiaMO 65211USA Swiss Federal institute for Forest Snow and Landscape Research WSLCH-8903 BirmensdorfSwitzerland School of Life Science Hebei UniversityBaoding 071000China

Alpine treeline ecotones are highly sensitive to climate *** low temperature-determined alpine treeline is expected to shift upwards in response to global ***,little is known about how temperature interacts with other important factors to influence the distribution range of tree species within and beyond the alpine treeline ***,we used a GF-2 satellite image,along with bioclimatic and topographic variables,to develop an ensemble suitable habitat model based on the species distribution modeling algorithms in *** investigated the distribution of suitable habitats for *** under three climate change scenarios(i.e.,low(SSP126),moderate(SSP370)and extreme(SSP585)future emission trajectories)between two consecutive time periods(i.e.,current-2055,and 2055-2085).By 2055,the potential distribution range of *** will expand under all three climate *** medium and high suitable areas will decline under SSP370 and SSP585scenarios from 2055 to ***,under the three climate scenarios,the uppermost altitudes of low suitable habitat will rise to 2,329 m a.s.l.,while the altitudes of medium and high suitable habitats will fall to 2,201 and2,051 m *** 2085,*** promotes the expansion of *** distribution range in Changbai Mountain,and this expansion will be modified by precipitation as climate warming *** interaction between temperature and precipitation plays a significant role in shaping the potential distribution range of *** in the alpine treeline *** study reveals the link between environmental factors,habitat distribution,and species distribution in the alpine treeline ecotone,providing valuable insights into the impacts of climate change on high-elevation vegetation,and contributing to mountain biodiversity conservation and sustainable development.

关键词： Biomod2 Birch Climate change Climate scenarios Habitat suitability Range shift Treeline species

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Carbon allocation in Picea jezoensis:Adaptation strategies of a non-treeline species at its upper elevation limit

引用

Forest Ecosystems 2024年第3期11卷 347-357页

作者： Renkai Dong Na Li Mai-He Li Yu Cong Haibo Du Decai Gao Hong S.He Key Laboratory of geographical Processes and Ecological Security in Changbai Mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun130024China School of Natural Resources University of MissouriColumbiaMO65211USA Swiss Federal institute for Forest Snow and Landscape Research WSL8903BirmensdorfSwitzerland Northeast institute of Geography and Agricultural Ecology Chinese Academy of SciencesChangchun130102China School of Life Science Hebei UniversityBaoding071002China

Understanding the physiological adaptations of non-treeline trees to environmental stress is important to understand future shifts in species composition and distribution of current treeline *** aim of the present study was to elucidate the mechanisms of the formation of the upper elevation limit of non-treeline tree species,Picea jezoensis,and the carbon allocation strategies of the species on Changbai *** employed the^(13)C in situ pulse labeling technique to trace the distribution of photosynthetically assimilated carbon in Picea jezoensis at different elevational positions(tree species at its upper elevation limit(TSAUE,1,700 m a.s.l.)under treeline ecotone;tree species at a lower elevation position(TSALE,1,400 m a.s.l.).We analyzed^(13)C and the non-structural carbohydrate(NSC)concentrations in various tissues following *** findings revealed a significant shift in carbon allocation in TSAUE compared to *** was a pronounced increase inδ^(13)C allocation to belowground components(roots,soil,soil respiration)in TSAUE compared to ***,the C flow rate within the plant-soil-atmosphere system was faster,and the C residence time in the plant was shorter in *** trends indicate enhanced C sink activity in belowground tissues in TSAUE,with newly assimilated C being preferentially directed there,suggesting a more conservative C allocation strategy by *** at higher elevations under harsher *** a strategy,prioritizing C storage in roots,likely aids in withstanding winter cold stress at the expense of aboveground growth during the growing season,leading to reduced growth of TSAUE compared to *** results of the present study shed light on the adaptive mechanisms governing the upper elevation limits of non-treeline trees,and enhances our understanding of how non-treeline species might respond to ongoing climate change.

关键词： ^(13)C pulse labeling Carbon distribution Non-structural carbohydrates(NSC) Non-treeline species Sink activity Stressful environments Upper elevation limit

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A four-band index for both liquid and solid water and its applications in the Aral Sea Basin

引用

Science China Earth Sciences 2024年第3期67卷 769-788页

作者： Bing YUE Xi CHEN Saibo LI Zhengping DU John WILSON Junhui YANG Yimen JIAO Shuangyan HUANG Chenghu ZHOU Xinjiang institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China institute of geographical Sciences and Natural Resources research Chinese Academy of SciencesBeijing 100101China Spatial Sciences institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.

关键词： Aral Sea Basin Syr river basin Amu river basin Water indices Water-coverage area Water deficit Climate change

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：