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SSRN 2022年

作者： Wang, Jun Hui, Dafeng Liu, Zhanfeng Yang, Long Wang, Faming Lu, Hongfang Ren, Hai CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical Garden Chinese Academy of Sciences Guangzhou510650 China Department of Biological Sciences Tennessee State University NashvilleTN37209 United States Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangdong Academy of Sciences Guangzhou510070 China Guangdong Provincial Key laboratory of Applied Botany China

Understanding the effects of nutrient availability on decomposition of both aboveground and belowground plant materials is needed to predict carbon and nutrient cycling in terrestrial ecosystems. In this study, we evaluated the influence of nitrogen (N) and phosphorus (P) additions on the decomposition of leaf and fine root (including higher-order and lower-order roots) litter of two dominant species ( Schima superba and Michelia macclurei ) in a subtropical evergreen broadleaved forest over two years. We found that neither N nor P addition affected the leaf litter decomposition rate of either species. However, N addition inhibited decomposition of S. superba lower-order roots, and P addition accelerated decomposition of M. macclurei higher-order roots. Lower-order roots decomposed more slowly than leaves or higher-order roots, perhaps because concentrations of acid-insoluble compounds are higher and concentrations of Ca and Mn are lower in the lower-order roots. As a consequence, lower-order roots tended to contribute more than higher-order roots or leaves to soil organic matter accumulation. P addition greatly increased P contents in leaf litter at the beginning of the experiment, and leaf litters in P addition plots immobilized P throughout the experiment. The results indicate that the effects of N and P addition on litter decomposition differ between leaves and fine roots. Analysis of only leaf litter decomposition may limit our understanding of how nutrient availability affects ecosystem biogeochemical processes. In simulating carbon and nutrient cycling in evergreen broadleaved forest, researches should ideally assess the decomposition of both aboveground and belowground plant materials. © 2022, The Authors. All rights reserved.

关键词： Tropics

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Study on urban form spatial differentiation based on road density analysis: A case study of Guangzhou, China

Advances in Transportation Studies

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Advances in Transportation Studies 2017年第SPECIAL ISSUE期1卷 39-52页

作者： Chen, S.P. Li, Y. Zhang, H.X. Yang, J.F. Yang, J. Department of Land-use Management Guangdong University of Finance and Economics Luntou Rd. 21 Guangzhou520320 China Open Laboratory of Geo-Spatial Information Technology and Application of Guangdong Province Guangzhou Institute of Geography Xianlie Zhong Rd.100 Guangzhou510070 China Guangzhou Yuntu Information Technology CO LTD Tangdong East Rd.13 Guangzhou510650 China

In essence, the urban form is the spatial movement of the city under the Ímpetus of the transportation development. The spatial differences in urban form are the result of the spatial arrangement of the various elements on urban transportation network, which is closely related to the regional transportation infrastructure construction level. The density of urban road network is an important index to measure the level of urban transportation infrastructure construction, but also an important parameter to characterize transportation network. Therefore, this paper takes Guangzhou as a study area, takes the rule grid of lxl km2 as the research unit, and uses the Kinging spatial interpolation and spatial autocorrelation analysis model to explore the spatial distribution pattem of the road network density in Guangzhou. Furthermore, an analysis of the spatial differentiation of urban form in Guangzhou based on the perspectives of urban road network density analysis is implemented. The results show that the spatial distribution of road density in Guangzhou has obvious agglomeration characteristics and zonal natures in the year of 2015. The high density of road network in the central regions is clustered in the historical downtowns and the Tianhe Central Business District, but the road network density in the south, northeast and northwest is low. This reveáis the uneven distribution of the urban road network density spatial distribution in Guangzhou. The density of the road network in the central regions is relatively high, with the difference between the surrounding areas being relatively signifícant, and the northem and southem parts are not connected or fully homogenized. The distribution of road network density is consistent with the regional trend of terrain and landform in the study area. Last, in the discussion of the urban spatial form planning and control, it is found that the distribution pattem of the road density in Guangzhou reflects the realization of urban spa

关键词： Urban transportation

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A comprehensive framework for seasonal controls of leaf abscission and productivity in evergreen broadleaved tropical and subtropical forests

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The Innovation 2021年第4期2卷 27-34页

作者： Xueqin Yang Jianping Wu Xiuzhi Chen Philippe Ciais Fabienne Maignan Wenping Yuan Shilong Piao Song Yang Fanxi Gong Yongxian Su Yuhang Dai Liyang Liu Haicheng Zhang Damien Bonal Hui Liu Guixing Chen Haibo Lu Shengbiao Wu Lei Fan Pierre Gentine SJoseph Wright Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies School of Atmospheric SciencesSun Yat-sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Lab of Guangdong for Utilization of Remote Sensing and Geographical Information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou 510070China Laboratoire des Sciences du Climat et de l’Environnement IPSLCEA-CNRS-UVSQUniversite Paris-Saclay91191 Gif sur YvetteFrance Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100871China College of Earth Sciences Chengdu University of TechnologyChengdu 610000China College of Forestry and Landscape Architecture South China Agricultural UniversityGuangzhou 510000China Department of Geoscience Environment&SocietyUniversite Libre de BruxellesBruxellesBelgium INRA UMR“Ecologie et Ecophysiologie Forestieres”Universite de Lorraine-INRA54280 ChampenouxFrance South China Botanical Garden Chinese Academy of SciencesGuangzhou 510650China School of Biological Sciences The University of Hong KongPokfulamHong Kong Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing 400715China Department of Earth&Environmental Engineering Columbia UniversityNew YorkNY 10027USA Smithsonian Tropical Research Institute Apartado 0843-03092BalboaPanama

Relationships among productivity,leaf phenology,and seasonal variation in moisture and light availability are poorly understood for evergreen broadleaved tropical/subtropical forests,which contribute 25% of terrestrial *** the one hand,as moisture availability declines,trees shed leaves to reduce transpiration and the risk of hydraulic *** the other hand,increases in light availability promote the replacement of senescent leaves to increase ***,we provide a comprehensive framework that relates the seasonality of climate,leaf abscission,and leaf productivity across the evergreen broadleaved tropical/subtropical forest *** seasonal correlation between rainfall and light availability varies from strongly negative to strongly positive across the tropics and maps onto the seasonal correlation between litterfall mass and productivity for 68 *** rainfall and light covary positively,litterfall and productivity also covary positively and are always greater in the wetter sunnier *** rainfall and light covary negatively,litterfall and productivity are always greater in the drier and sunnier season if moisture supplies remain adequate;otherwise productivity is smaller in the drier sunnier *** framework will improve the representation of tropical/subtropical forests in Earth system models and suggests how phenology and productivity will change as climate change alters the seasonality of cloud cover and rainfall across tropical/subtropical forests.

关键词： tropical forest leaf abscission and productivity plant adaptive strategy climate and phenology regime climatic driver

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information Entropy Embedded Back Propagation Neural Network Approach for Debris Flows Hazard Assessment

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IOP Conference Series: Earth and Environmental Science 2020年第1期453卷

作者： Yan Yu Jun Wang Science and Technology Library of Guangdong Province/Guangdong Institute of Scientific & Technical Information and Development Strategy Guangzhou 510070 Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangzhou 510070

The purpose of the study is to propose a new method to assess debris flow hazard by embedding Shannon's information entropy in back propagation neural network. The procedure was divided into two parts. One was to establish a mathematical model for debris-flow hazard assessment based on Shannon's information entropy forming input and output data sets of back propagation neural network. The other was to establish a back propagation neural network technique for characterizing debris flow dynamic hazard. The proposed method was employed to assess debris flow hazard of Shenxi gully basin, Sichuan province, China. The result shows that the assessed result of proposed method is highly consistent with the result of field surveys. The proposed method can reflect the interaction, nonlinearity and dynamic process of background variable factors and can be used to debris flow hazard assessment, risk management and mitigation of debris flows.

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Validation of fuel and emission calculator model for fuel consumption estimation

Advances in Transportation Studies

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Advances in Transportation Studies 2017年第SPECIAL ISSUE期1卷 53-62页

作者： Li, Z.Y. Li, J.H. Yang, J.F. Li, Y. He, J.R. Togotech Inc 822E 78th Ave Suite 101 DenverCO80229 United States Guangzhou Vocational College of Science and Technology GuangZhou510550 China Guangzhou Yuntu Information Technology CO LTD Tangdong East Rd.13 Guangzhou510650 China Open Laboratory of Geo-spatial Information Technology and Application of Guangdong Province Guangzhou Institute of Geography Xianlie Zhong Rd.100 Guangzhou510070 China Foshan Municipal People’s Government Office Foshan528200 China

The vehicle emission pollution is a major concern in the society. The electricity vehicle has been widely studied. Traditional electricity vehicle energy and emission control consider to integrate the dynamic route information to optimize the usage of energy. However, the research on transit electricity vehicle energy control is limited. Thus, the research focuses on studying the transit electricity vehicle energy consumption model, Fuel and Emission Calculator(FEC). The paper assesses the accuracy of the model for the buses in specific transit routes under different transit scenarios. The result shows that the average difference between the FEC model and the actual performance is 10.86%. After grade modification, the difference reduces fromlO.86% to 7.66%. The trip length also affects the FEC accuracy. A longer trip length indicates a higher model accuracy. The results also reveáis that the FEC prediction performance is quite different under different operation mode. © 2017, Aracne Ed. All rights reserved.

关键词： Vehicles

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Spatial Distribution of Rare Earth Elements and Their Impact Factors in an Area with a High Abundance of Regolith-Hosted Deposits

SSRN

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SSRN 2023年

作者： Lin, Zhuoling Zhang, Yaduo Liang, Xiaoliang Huang, Guangqing Fan, Fenglei Yin, Xiaoling Chen, Zhihao Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou510640 China Guangdong Public Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangdong Academy of Sciences Guangzhou510070 China School of Geography South China Normal University Guangzhou510631 China University of Chinese Academy of Sciences Beijing100049 China Guangdong Provincial Key Laboratory of Mineral Physics and Material Research & Development Guangzhou510640 China College of Natural Resources and Environment South China Agricultural University Guangzhou510642 China

Rare earth elements (REEs) are critical metals for manufacturing numerous high-tech products, but at high concentrations, pose potential hazards owing to their toxicity to animals and human health. Despite the widespread occurrence of regolith-hosted REEs across South China, their spatial distribution characteristics in soils and attendant influencing factors remain largely unknown. This knowledge gap impedes the exploration of regolith-hosted REE deposits and the assessment of the environmental risks associated with REEs. To address this issue, 180 soil samples were collected from Meizhou City, guangdong Province, a region known for its high abundance of regolith-hosted REEs. Subsequently, the correlations between REE enrichment/fractionation and various factors, i.e., topography, climate conditions, land use, and landform were analysed using the geo-detector method. The results revealed a highly uneven spatial distribution of REEs and their fractionation features with some regions displaying distinct spatial patterns. Elevation was the dominant factor influencing this distribution, and showed strong correlations with the concentrations of REEs, light REEs (LREEs) and heavy REEs (HREEs);the LREE/HREE ratio;and the positive Ce anomaly (δCe). The negative Eu anomaly (δEu) showed a good correlation with rock type. The enrichment and fractionation of REEs indicated a coupling among the abovementioned factors. The crucial scopes of the predominant factors were identified using a risk detector. For REE enrichment, areas with elevations of 137–148 m, precipitation levels of 1553–1574 mm, annual average land surface temperatures of 30.4–30.5 °C, leaf area index values of 22–29 and relief degrees of land surface of 21.4–29.9 m showed the highest average abundance within each type (scope) of the predominant factors. These findings highlight the key factors affecting REE distribution, thereby aiding the efficient utilization of regolith-hosted REE resources and the assessment

关键词： Soils

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Spatial distribution of rare earth elements and their impact factors in an area with a high abundance of regolith-hosted deposits

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Chemosphere 2024年 352卷 141374页

作者： Lin, Zhuoling Zhang, Yaduo Liang, Xiaoliang Huang, Guangqing Fan, Fenglei Yin, Xiaoling Chen, Zhihao Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Guangdong Public Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangdong Academy of Sciences Guangzhou 510070 China University of Chinese Academy of Sciences Beijing 100049 China School of Geography South China Normal University Guangzhou 510631 China Guangdong Provincial Key Laboratory of Mineral Physics and Material Research & Development Guangzhou 510640 China College of Natural Resources and Environment South China Agricultural University Guangzhou 510642 China

Despite the widespread occurrence of regolith-hosted rare earth elements (REEs) across South China, their spatial distribution characteristics in soils and their impact factors remain largely uncertain. This knowledge gap impedes the exploration of regolith-hosted REE deposits and the assessment of the environmental risks associated with REEs. To address this issue, 180 soil samples were collected from Meizhou City, guangdong Province, a region known for its high abundance of regolith-hosted REEs. Subsequently, the correlations between REE enrichment/fractionation and various factors, i.e., topography, climate conditions, land use, and landform were analysed using the geo-detector method. The results revealed a highly uneven spatial distribution of REEs and their fractionation features with some regions displaying distinct spatial patterns. Elevation was the dominant factor influencing this distribution, and showed strong correlations with the concentrations of REEs, light REEs (LREEs) and heavy REEs (HREEs);the LREE/HREE ratio;and the positive Ce anomaly (δCe). The negative Eu anomaly (δEu) showed a good correlation with rock type. The enrichment and fractionation of REEs indicated a coupling among the abovementioned factors. For REE enrichment, areas with elevations of 138–148 m, precipitation levels of 1553–1574 mm, annual average land surface temperatures of 30.4–30.5 °C, leaf area index values of 22–29 and surface cutting degree of 21.5–29.9 m showed the highest average abundance within each type (scope) of the predominant factors. These findings highlight the key factors affecting REE distribution, thereby aiding the efficient utilization of regolith-hosted REE resources and the evaluation of their environmental risks. © 2024 Elsevier Ltd

关键词： Geo-detector REE enrichment REE fractionation Soil Spatial heterogeneity Topography

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Multi-drivers and multi-mechanism analysis for city-level energy consumption in Suzhou based on the extended STIRPAT model

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IOP Conference Series: Earth and Environmental Science 2020年第1期467卷

作者： Yahui Ma Zhe Zhang Molin Huo Lei Guo Changjian Wang Zeng Li State Grid (Suzhou) City & Energy Research Institute Suzhou Jiangsu 215000 China State Grid Energy Research Institute Co. Ltd Beijing 100000 China Guangzhou Institute of Geography Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Guangdong 510070 China

Examining the driving factors of energy consumption at city scale, is an important measure for effectively achieving energy saving and emission reduction. An extended STIRPAT model based on the classical IPAT identity is adopted to uncover the main drivers for total energy consumption in Suzhou, an important manufacturing city in China, during 2006 to 2016. The main conclusions are as follow: (1) Foreign trade, economic growth, and industrialization are the three dominant contributors to energy consumption increments. Furthermore, quite significant portion of Suzhou's foreign trade is processing exports. The export products are mainly high-energy consumption such as electromechanical, chemical, textile, etc. The export-oriented economy is accelerating the economic growth and industrialization, and also strengthening the energy intensive regional development mode. (2) Urbanization and population size are also the main driving factors for the rapid growth of energy consumption in Suzhou. The population scale effect exhibits the urban function of absorb employment and agglomerate population in Suzhou, it also demonstrates the growing energy demands caused by population growth and the accompanying urbanization process. (3) Energy consumption intensity and energy consumption structure are the important influencing factor in curbing energy consumption in Suzhou. Energy saving effects played by energy consumption intensity are stronger than energy consumption structure. The coal-based energy consumption structure has not been changed fundamentally during the research period. Therefore, the energy saving effect of energy structure has not been fully utilized. The current and future major strategies for controlling energy consumption in Suzhou should further improve energy utilization efficiency, optimize energy consumption structure, and reduce the proportion of coal consumption.

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Area Estimation and Distribution Analysis of Subsurface Flow Constructed Wetlands at Regional Scale--Take Guangzhou City for Example

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IOP Conference Series: Earth and Environmental Science 2017年第1期51卷

作者： S X Yuan G L Tang H X Xiong J Chen X L Yin G Q Huang Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography 100 Xianlie Middle Rd 510070 Yuexiu Guangzhou Guangdong P. R. China Guangzhou Institute of Geochemistry Graduate School of the Chinese Academy of Sciences 510640 Wushan Guangzhou Guangdong China University of Chinese Academy of Science Beijing 100049 China

In this paper, Area of Constructed Wetlands (CWs) required for treatment of domestic sewage generated by 13 million people was calculated in accordance with the distribution of existing population in Guangzhou City and mathematical model of CWs. By comparing this with land use data, the distribution of constructed wetlands at construction regional scale was simulated with GIS. The results show that, Guangzhou generate about 3.88 million m3 domestic sewage per day, which shall be treated with 59.37 km2 CWs. Assuming that a single wetland bed is 300 m2, total 197,905 wetland beds shall be required in the city. Based on the analysis and statistics on data of second national land survey of Guangzhou City with GIS, there are enough ponds, bare lands, other grasslands and other garden plots in Guangzhou that can be used for construction of regional scale CWs, but the distribution of available lands in different regions is uneven. Constructed wetlands at regional scale are mainly distributed around Baini Channel, Tianma River, Xinjie River, Liuxi River Valley, Zengjiang River Valley and on both sides of the Pearl River through Panyu and Nansha.

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Analysis of the impact of precipitation and temperature on the streamflow of the Ürümqi River, Tianshan Mountain, China

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IOP Conference Series: Earth and Environmental Science 2018年第1期191卷

作者： Y C Liu K Zhao Y Liu X L Yin D Labat School of Resources and Environmental Engineering Jiangxi University of Science and Technology Jiangxi Ganzhou 341000 Jiangxi Province China Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangzhou 510070 Guangdong Province China Géosciences Environnement Toulouse (GET) Université de Toulouse (CNRS IRD OMP) 14 Avenue Edouard Belin 31400 Toulouse France

This study explores the relationship between streamflow time variability and precipitation and air temperature variability, in the upper reaches of the Ürümqi River in northwestern China. Wavelet analyses are adopted to analyse the multi-time scale features of monthly temperatures, monthly precipitations and monthly runoffs during the years between 1958 and 2006. Results of continuous wavelet transform imply a statistically significant cycle over an approximately 12-month period in the temporal fluctuations of monthly air temperature, precipitation and runoff. Furthermore, monthly temperature shows 66-month and 96-month cycles while monthly precipitation shows 6-month, 30-month and 72-month cycles. Monthly runoff has 6-month, 24-month, 36-month and 72-month cycles. The results of cross wavelet transform and wavelet coherence show that monthly runoff variability correlates with precipitation and air temperature fluctuations at 6-month and 12-month respectively. Other time-scale correlations at 1-year, 2-year, 3-year and 6-year marks are also highlighted between the different time series. These correlations are then explained considering the alpine characteristics of the catchment. Higher air temperatures in the upper reaches of the Ürümqi River accelerate snow melt and intensify evaporation, thus the relationship between air temperature and runoff is uncertain during different seasons. Overall, summer air temperature controls the annual runoff and precipitation provides a sustained water supply to the upper Ürümqi River. They constitute the dominant factors that explain the temporal variations of streamflow in the upper Ürümqi River. Univariate and cross-wavelet analyses on runoff and climate variability clearly offer a useful tool in hydro-meteorological issues in alpine areas.

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