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Water Science and Engineering 2013年第1期6卷 44-58页

作者： Jun DU Chang-xing SHI Chen-di ZHANG State Key Laboratory of Hydroscience and Engineering Tsinghua University Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences

This paper focuses on the effects of precipitation and vegetation coverage on runoff and sediment yield in the Jinsha River Basin. Results of regression analysis were taken as input variables to investigate the applicability of the adaptive network-based fuzzy inference system （ANFIS） to simulating annual runoff and sediment yield. Correlation analysis indicates that runoff and sediment yield are positively correlated with the precipitation indices, while negatively correlated with the vegetation indices. Furthermore, the results of stepwise regression show that annual precipitation is the most important factor influencing the variation of runoff, followed by forest coverage, and their contributions to the variation ofrunoffare 69.8% and 17.3%, respectively. For sediment yield, rainfall erosivity is the most important factor, followed by forest coverage, and their contributions to the variation of sediment yield are 49.3% and 24.2%, respectively. The ANFIS model is of high precision in runoff forecasting, with a relative error of less than 5%, but of poor precision in sediment yield forecasting, indicating that precipitation and vegetation coverage can explain only part of the variation of sediment yield, and that other impact factors, such as human activities, should be sufficiently considered as well.

关键词： precipitation vegetation coverage runoff sediment yield,＂ adaptive network-basedfuzzy inference system （ANFIS）,＂ Jinsha River Basin

Spatiotemporal changes in vegetation coverage and its driving factors in the Three-River Headwaters Region during 2000-2011

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Journal of Geographical Sciences 2014年第2期24卷 288-302页

作者： LIU Xianfeng ZHANG Jinshui ZHU Xiufang PAN Yaozhong LIU Yanxu ZHANG Donghai LIN Zhihui State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing 100875 China College of Resources Science & Technology Beijing Normal University Beijing 100875 China College of Urban and Environmental Sciences Peking University Beijing 100871 China College of Tourism and Environment Shaanxi Normal University Xi'an 710062 China

The Three-River Headwaters Region （TRHR）, which is the source area of the Yangtze River, Yellow River, and Lancang River, is of key importance to the ecological secu- rity of China. Because of climate changes and human activities, ecological degradation oc- curred in this region. Therefore, ＂The nature reserve of Three-River Sou,＇ce Regions＂ was established, and ＂The project of ecological protection and construction for the Three-River Headwaters Nature Reserve＂ was implemented by the Chinese government. This study, based on MODIS-NDVI and climate data, aims to analyze the spatiotemporal changes in vegetation coverage and its driving factors in the TRHR between 2000 and 2011, from three dimensions. Linear regression, Hurst index analysis, and partial correlation analysis were employed. The results showed the following：（1） In the past 12 years （2000-2011）, the NDVI of the study area increased, with a linear tendency being 1.2%/10a, of which the Yangtze and Yellow River source regions presented an increasing trend, while the Lancang River source region showed a decreasing trend. （2） vegetation coverage presented an obvious spatial difference in the TRHR, and the NDVI frequency was featured by a bimodal structure. （3） The area with improved vegetation coverage was larger than the degraded area, being 64.06% and 35.94%, respectively during the study period, and presented an increasing trend in the north and a decreasing trend in the south. （4） The reverse characteristics of vegetation cov- erage change are significant. In the future, degradation trends will be mainly found in the Yangtze River Basin and to the north of the Yellow River, while areas with improving trends are mainly distributed in the Lancang River Basin. （5） The response of vegetation coverage to precipitation and potential evapotranspiration has a time lag, while there is no such lag in the case of temperature. （6） The increased vegetation coverage is mainly attributed to the warm-wet climate change and the implementation of the ecological protectio

关键词： vegetation coverage spatiotemporal change future trend influence factors Three-River HeadwatersRegion

Investigating natural drivers of vegetation coverage variation using MODIS imagery in Qinghai, China

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Journal of Arid Land 2016年第1期8卷 109-124页

作者： ZHOU Lei LYU Aifeng China National Environmental Monitoring Center Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

The climatically sensitive Qinghai province of China has been recognized as a hotspot for studies on the feedbacks of terrestrial ecosystems to global climate change. Thus, investigating vegetation coverage and its natural drivers in Qinghai is an important focus of ecosystem research. On the basis of Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced vegetation Index (EVI) time series data, we estimated the vegetation coverage in this region using the dimidiate pixel model. Trend analyses, correlations between meteorological parameters, changes in vegetation coverage, and the temporal and spatial relationships between soil texture and vegetation coverage were used to investigate the possible drivers of vegetation coverage variations. The results indicated that the reduction of vegetation coverage slowed down in the period from 2000 to 2012. Annual mean temperature was the main climatic driver of the total extremely low and low vegetation coverage areas in Qinghai, followed by the precipitation anomalies. The extremely low and low vegetation coverage areas were mainly distributed in regions with a mean annual relative air humidity of vegetation coverage areas were mainly characterized by sandy clay loam soil, followed by loamy sand and sandy soil. Regions with sandy loam or loam soil have the greatest risk of vegetation coverage reductions. Knowledge of vegetation coverage variation and its natural drivers in the ecologically fragile region of Qinghai can provide scientific support for managing environmental change and desertification.

关键词： vegetation coverage remote sensing MODIS climate change

Correlation analysis between vegetation coverage and climate drought conditions in North China during 2001–2013

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Journal of Geographical Sciences 2017年第2期27卷 143-160页

作者： GONG Zhaoning ZHAO Shuyi GU Jinzhi Beijing Laboratory of Water Resources Security Key Laboratory of 3D Information Acquisition and Application Ministry of Education Key Laboratory of Resources Environment and GIS of Beijing College of ResourceEnvironment&Tourism Capital Normal UniversityBeijing 100048China

Climate change is one of the most important factors that affect vegetation distribution in North China. Among all climatic factors, drought is considered to have the most significant effect on the environment. Based on previous studies, the climate drought index can be used to assess the evolutionary trend of the ecological environment under various arid climatic conditions. It is necessary for us to further explore the relationship between vegetation coverage（index） and climate drought conditions. Therefore, in this study, based on MODIS-NDVI products and meteorological observation data, the Palmer Drought Severity Index（PDSI） and vegetation coverage in North China were first calculated. Then, the interannual variations of PDSI and vegetation coverage during 2001–2013 were analyzed using a Theil-Sen slope estimator. Finally, an ecoregion perspective of the correlation between them was discussed. The experimental results demonstrated that the PDSI index and vegetation coverage value varied over different ecoregions. During the period 2001–2013, vegetation coverage increased in the southern and northern mountains of North China, while it showed a decreasing trend in the Beijing-Tianjin-Tangshan City Circle area and suburban agricultural zone located in Hebei Province and Henan Province）. Over 13 years, the climate of the northeastern part of North China became more humid, while in the southern part of North China, it tended to be dry. According to the correlation analysis results, 73.37% of North China showed a positive correlation between the vegetation coverage and climate drought index. A negative correlation was observed mainly in urban and suburban areas of Beijing, Tianjin, Hebei Province, and Henan Province. In most parts of North China, drought conditions in summer and autumn had a strong influence on vegetation coverage.

关键词： North China vegetation coverage PDSI ecoregion correlation analysis

Evaluation of Erosion Rates in Relation to vegetation coverage Level-Case Study:Kukësi and Hasi Regions,Albania

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Journal of Environmental Science and Engineering(B) 2022年第6期11卷 225-228页

作者： Oltion Marko Joana Gjipalaj Blerina Beqaj Konalsi Gjoka Sali Fazliu Department of Environmental Engineering Faculty of Civil EngineeringPolytechnic University of TiranaTirana 1023Albania Freelancer Expert Prishtina 10010Kosovo

Soil erosion is one of the most destructive phenomena of earth causing the loss of land,leading to increased pollution and sedimentation in streams and rivers,clogging these waterways.Due to soil erosion,degraded lands are also often less able to hold onto water,which can worsen flooding.Among all natural causes of soil erosion such as rainfall intensity,temperature and wind,the human activity;massive deforestation and intensive agriculture,including the latest climate changes are considered as very important factors especially nowadays.Thus,evaluating the soil erosion appears very important in order to prevent the phenomena.In this study the soil erosion in forest and pasture areas in Kukësi and Hasi regions(Albania)was evaluated,and classified depending on the degree of coverage by forest vegetation.Detailed information for the above factor was gathered from site visits and national databases of different institutions.Results show that erosion is present in forest and pasture areas in Kukësi and Hasi Regions and is mainly caused by human activities such as large deforestation,intensive use of agricultural land,etc.There is a need to take effective measures and use advanced methods to prevent or control soil erosion not only in Kukësi and Hasi regions,but in all Albanian watersheds.

关键词： Soil erosion vegetation coverage Albania

Effects of vegetation coverage on the spatial distribution of soil nematode trophic groups

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Frontiers in Biology 2008年第1期3卷 63-67页

作者： Jianfeng HUA Yong JIANG Wenju LIANG Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016China Graduate School of the Chinese Academy of Sciences Beijing 100049China

The spatial variability of total soil nematodes and trophic groups in bare and fallow plots in Shenyang Experi-mental Station of Ecology,ChineseAcademy of Sciences was examined using geostatistics combined with classic statistics.Results showed that the soil pH value had a negative effect on plant-parasites in both bare and fallow plots;the mean number of total nematodes was significantly higher in fallow plots than in bare plots,which was 1485.3 and 464.0 individuals per 100 g dry soil in fallow and bare plots,respectively;the nugget(C_(0))/sill(C_(0)+C)ratio of total nematodes,plant-parasites and bacterivores were lower in fallow plots(27.3%-45.6%)than in bare plots(49.5%-100%);the spatial distribution of total nematodes and trophic groups was found to be different between fallow and bare plots,which indicated that vegetation coverage had an effect on soil nematodes.

关键词： vegetation coverage soil nematode trophic group spatial distribution geostatistics

Monitoring of vegetation coverage based on high-resolution images

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Forestry Studies in China 2007年第4期9卷 256-261页

作者： Zhang Li Li Li-juan Liang Li-qiao Li Jiu-yi Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 P. R. China Graduate University of the Chinese Academy of Sciences Beijing 100039 P. R. China

Measurement of vegetation coverage on a small scale is the foundation for the monitoring of changes in vegetation coverage and of the inversion model of monitoring vegetation coverage on a large scale by remote sensing. Using the object-oriented analytical software, Definiens Professional 5, a new method for calculating vegetation coverage based on high-resolution images （aerial photographs or near-surface photography） is proposed. Our research supplies references to remote sensing measurements of vegetation coverage on a small scale and accurate fundamental data for the inversion model of vegetation coverage on a large and intermediate scale to improve the accuracy of remote sensing monitoring of changes in vegetation coverage.

关键词： vegetation coverage remote sensing measurement high-resolution image object-orientation

The research of vegetation coverage classification using NDVI data in China

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The research of vegetation coverage classification using NDV...

vegetation coverage Changes in the West Qinling Region from 2000 to 2010:A Case Study of Longnan City

International Conference on Info-Tech and Info-Net (ICII 2001)

作者： Cheng, CQ Wang, H Ma, T Li, B Peking Univ Inst Remote Sensing & GIS Beijing 100871 Peoples R China

ISBN: (纸本)7900081585

The Normalized Difference vegetation Index (NDVI) is very important index, which often is a measure of the amount and vigor of vegetation at the surface. In general, the magnitude of NDVI is related to the level of photosynthetic activity in the observed vegetation. There have been quite a lot of successful examples in using this Index to classify vegetation and to forecast the amount of crop in China. We used 12 monthly NOAA AVHRR NDVI data pretreated necessarily of the year 1999 to establish the standard deviation matrix of every ground surface element all over China, and then estimated the comparability between every two elements. But because of some deficiency when it is used to demonstrate the difference of NDVI changes within only a part of time, two factors should be considered, which include a factor for controlling range changes and a factor for controlling the direction of time changes. To establish the first factor is to distinguish the surface elements which have similar standard deviation but have different NDVI range changes in different range of time. To establish the second factor is to distinguish the change direction of all the NDVI of different elements. The standard deviation and the factors form a set, which helped us to analyze the conformation and difference of changes between elements, and finally we gained the classified result, And referring to Chinese vegetation and zoology distributing map, we discussed every class in our result carefully, which was explained further.

关键词： NDVI vegetation coverage factor set classification

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Asian Agricultural Research 2016年第8期8卷 81-85,90页

作者： Ming FANG Qiuqiu LI Chuansheng WANG Meng LI Key Laboratory of Regional Sustainable Development Modeling CAS University of Chinese Academy of Sciences Institute of Geographic Sciences and Resources Research CAS

As the main content of terrestrial ecosystem study,vegetation coverage change has gained extensive attention in the process of global climate change and sustainable development recently.Based on MODIS NDVI data from June to October during 2000-2010,taking Longnan City as a case area,this paper develops the calculation method of vegetation coverage(VC) by using Pixel Dichotomy model and analyzes the spatial-temporal variation of vegetation coverage in the West Qinling region by using simple linear regression and standard deviation method.The results show that vegetation coverage remains stable and is significantly correlated with temperature and precipitation during the decade.The vegetation coverage of 90% of study area shows stability with small annual variation and also is consistent with the spatial distribution of forest land;the vegetation coverage in the remaining study areas shows a growing trend with significant variation and also is consistent with the spatial distribution of farmland and grassland,especially in Huicheng Basin,Xili Basin and adret slope of Bailongjiang River Valley,indicating that Project about the Conversion of Degraded Farmland into Forest has made a great contribution to vegetation coverage increase.This paper proves the effect of ecology construction in the West Qinling region since the late 20 th century.All the findings also provide references for local ecological environment construction and sustainable development.

关键词： vegetation coverage Spatial and temporal change West Qinling Region

NUMERICAL STUDY OF EFFECT OF vegetation coverage ON DRYNESS OF CLIMATE

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Journal of Geographical Sciences 1991年第1期 40-48页

作者： Luo Zhexian Nanjing Institute of Meteorology

A set of numerical experiments running for over70 days are designed and performed with an improved Lorenz low-order moist spectral model.It involves in physical processes such as ground-absorl)ed solar radiation.Sellsible heat trailsportation,latent heat release,hydrological cycle,convective adjustment,frictional dissipation,tOpographic influence,ground heat balance and sea-1and thermal contrast.Results show that the extensive growth in vegetation coverage gives rise tO the increase in model rainfall and decrease in the number of success.1ye rainless days,SUggesring that vegetation coverage growth makes it possible tO lead to some modifications of dry climate.

关键词： vegetation coverage dry climate model experiment