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Vegetation fractional coverage change in a typical oasis region in Tarim River Watershed based on remote sensing

Journal of Arid Land 2013年第1期5卷 89-101页

作者： Fei ZHANG Tashpolat TIYIP JianLi DING Mamat SAWUT verner Carl johnson NigaraTASHPOLAT DongWei GUI College of Resources and Environment Science Xinjiang University Urumqi 830046 China Key Laboratory of Oasis Ecology Xinjiang University Urumqi 830046 China Department of Physical and Environmental Sciences Colorado Mesa University Grand Junction Colorado 81501 USA Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Cele National Station of Observation & Research for Desert-Grassland Ecosystem in Xinjiang Cele 848300 China

Vegetation fractional coverage （VFC） is an important index to describe and evaluate the ecological system. The vegetation index is widely used to monitor vegetation coverage in the field of remote sensing （RS）. In this paper, the author conducted a case study of the delta oasis of Weigan and Kuqa rivers, which is a typical saline area in the Tarim River Watershed. The current study was based on the TM/ETM＋ images of 1989, 2001, and 2006, and supported by Geographic Information System （GIS） spatial analysis, vegetation index, and dimidiate pixel model. In addition, VBSl （vegetation, bare soil and shadow indices） suitable for TM/ETM＋ irrlages, constructed with FCD （forest canopy density） model principle and put forward by ITTO （International Tropical Timber Organization）, was used, and it was applied to estimate the VFC. The estimation accuracy was later prow^n to be up to 83.52%. Further, the study analyzed and appraised the changes in vegetation patterns and revealed a pattern of spatial change in the vegetation coverage of the study area by producing the map of VFC levels in the delta oasis. Forest, grassland, and farmland were the three main land-use types with high and extremely-high coverage, and they played an important role in maintaining the vegetation. The forest area determined the changes of the coverage area, whereas the other two land types affected the directions of change. Therefore, planting trees, protecting grasslands, reclaiming farmlands, and controlling unused lands should be included in a long-term program because of their importance in keeping regional vegetation coverage. Finally, the dynamic variation of VFC in the study area was evaluated according to the quantity and spatial distribution rendered by plant cover diigital images to deeply analyze the reason behind the variation.

关键词： vegetation fractional coverage (VFC) VBSI (vegetation, bare soil and shadow indices) dimidiate pixel model delta oasis of Weigan and Kuqa rivers

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Using a modified PAP/RAC model and GIS-for mapping water erosion and causal risk factors:Case study of the Asfalou watershed,Morocco

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International Soil and Water Conservation Research 2022年第2期10卷 254-272页

作者： Jad Tahouri Abdelhamid Sadiki L'houcine Karrat verner Carl johnson Ngai weng Chan Zhang Fei Hsiang Te Kung Departement des Sciences de la Terre Université Sidi Mohammed Ben AbdellahFaculté des Sciences Dhar MahrazLaboratoire de GeosciencesEnvironnement et Ressources Associées(LGERA)B.P.1796FèsAtlasMorocco International Association of Seismology and Physics of the Earth’s Interior(IASPEI) Japan Department of Physical and Environmental Sciences Colorado Mesa UniversityGrand JunctionCO81501USA School of Humanities University Sains Malaysia11800PenangMalaysia Resources and Environment Department Xinjiang UniversityUrumqi830046People's Republic of China Key Laboratory of Oasis Ecology Ministry of EducationXinjiang UniversityUrumqi830046People's Republic of China Key Laboratory of Xinjiang Wisdom City and Environment Modeling Urumqi830046People's Republic of China Departments of Earth Sciences The University of MemphisMemphisTN38152USA

Our work focuses on the assessment of trends,erosion states and causal risk factors for soil erosion of the Asfalou watershed through the use of the Priority Actions Program/Regional Activity Center(PAP/RAC).This qualitative study model for water erosion makes it possible to assess susceptibility and determine potential fragile areas in order to diagnose the state of soil *** adopted the PAP/RAC crossed matrices,the geographic information system(GIS)and remote sensing(RS)to develop the classical *** method is based on three main approaches:predictive,descriptive and *** soil types,slope length(LS)and climatic factors into our model,including rainfall erosivity(R),slope exposure,soil moisture index(SMI)and land surface temperature(LST),improved the reli-ability of our *** correlation analysis identified these factors that explain erosion states and the risk of soil *** coefficients of determination(R2)of the various erosive states resulting from the modified PAP/RAC approach explain respectively 98.30%,77%and 49.3%of the observed variability of the erosive *** factors provide information on the current state of soil degradation depending on the degree of influence of the different factors that control *** descriptive approach has shown that soil loss manifests itself in different forms,whether for sheet erosion(L)and ravines(C1)succes-sively affecting 79.95%and 17.84%of the *** integration approach identifies factors and areas requiring intervention to counter the effects of soil erosion in the Asfalou watershed effectively and sustainably.

关键词： Modified PAP/RAC Model GIS Water erosion Causative factors Soil erosion

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A Method of Soil Salinization Information Extraction with SVM Classification Based on ICA and Texture Features

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Agricultural Science & Technology 2011年第7期12卷 1046-1049,1074页

作者： ZHANG Fei TASHPOLAT Tiyip KUNG Hsiang-te DING Jian-li MAMAT.Sawut verner johnson HAN Gui-hong GUI Dong-wei College of Resources and Environment Science Xinjiang UniversityUrumqi 830046 Key Laboratory of Oasis Ecology Xinjiang UniversityUrumqi 830046 Department of Earth Sciences the University of MemphisMemphisTN 38152USA Graduate School of Xinjiang University Urumqi 830046 Department of Physical and Environmental Sciences Mesa State College in Grand Junction CO 81501USA Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011 Cele National Station of Observation ＆ Research for Desert-Grassland Ecosystem in Xinjiang Cele 848300

Salt-affected soils classification using remotely sensed images is one of the most common applications in remote sensing,and many algorithms have been developed and applied for this purpose in the *** study takes the Delta Oasis of Weigan and Kuqa Rivers as a study area and discusses the prediction of soil salinization from ETM +Landsat *** reports the Support Vector Machine(SVM) classification method based on Independent Component Analysis(ICA) and Texture ***,the letter introduces the fundamental theory of SVM algorithm and ICA,and then incorporates ICA and texture *** classification result is compared with ICA-SVM classification,single data source SVM classification,maximum likelihood classification(MLC) and neural network classification qualitatively and *** result shows that this method can effectively solve the problem of low accuracy and fracture classification result in single data source *** has high spread ability toward higher array *** overall accuracy is 98.64%,which increases by10.2% compared with maximum likelihood classification,even increases by 12.94% compared with neural net classification,and thus acquires good ***,the classification method based on SVM and incorporating the ICA and texture features can be adapted to RS image classification and monitoring of soil salinization.

关键词： Independent component analysis(ICA) Texture features Support vector machine(SVM) Soil salinizaiton

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