نتایج جستجو برای: desertification indices

تعداد نتایج: 84578  

Journal: :Remote Sensing 2016
Xiangjian Xie Shufang Tian Peijun Du Wenfeng Zhan Alim Samat Jike Chen

Considering the important roles of carbonate rock fraction in karst rocky desertification areas and their potential for indicating damage to vegetation, improved knowledge is desired to assess the application of spectroscopy and remote sensing to characterizing and quantifying the biophysical constituents of karst landscapes. In this study, we examined the spectra of major surface constituents ...

Journal: :مرتع و آبخیزداری 0
سید هدایت پروری اصل دانش آموخته کارشناسی ارشد رشته بیابان¬زدایی، دانشکده منابع طبیعی، دانشگاه زابل، ایران احمد پهلوانروی استادیار، دانشکده منابع طبیعی، دانشگاه زابل، ایران علیرضا مقدم نیا استادیار، دانشکده منابع طبیعی، دانشگاه زابل، ایران

desertification is the consequence of series of processes in which climate change and human activities are more important factors than others. arid and semi-arid areas have occupied most parts of iran. sistan region is one of arid areas of iran where wind erosion is an important factor of land degradation and soil deterioration. for classification of desertification intensity, several methods h...

Journal: :Proceedings. Mathematical, physical, and engineering sciences 2016
Karna Gowda Yuxin Chen Sarah Iams Mary Silber

A particular sequence of patterns, 'gaps→labyrinth→spots', occurs with decreasing precipitation in previously reported numerical simulations of partial differential equation dryland vegetation models. These observations have led to the suggestion that this sequence of patterns can serve as an early indicator of desertification in some ecosystems. Because parameter values in the vegetation model...

2001
W. Tao

Land desertification is one of the most serious environmental and social-economic problems in the North China. The processes of desertification mainly have being controlled by the interaction of human activities and fragile eco-environment, that means the pattern and intension of landuse are major factors for development or reverse of desertification. Because of the increasing pressure of popul...

Journal: :desert 2005
h. ahmadi e. abrisham m. r. ekhtesasi m. jafari a. golkarian

there are different models for mapping and evaluation of desertification condition, such as global fao_unep model. there are also several models for evaluation of desertification in iran. in this study, tow fol/owing methods was used: 1-icd method, (iranian classification of desertification). 2- micd method, (modified iranian classification of desertification). in this research, at first, these...

2009
Duanyang Xu Xiangwu Kang Dongsheng Qiu Dafang Zhuang Jianjun Pan

Desertification is a serious threat to the ecological environment and social economy in our world and there is a pressing need to develop a reasonable and reproducible method to assess it at different scales. In this paper, the Ordos Plateau in China was selected as the research region and a quantitative method for desertification assessment was developed by using Landsat MSS and TM/ETM+ data o...

In order to deal desertification phenomenon it is necessary to identify its producing and increases causes. For this purpose several studies conducted inside and outside the country that have been led to submit regional models.. Each of these models has different pattern and use different indicators which can lead to different results. In this study, Fakhrabad plain of Mehriz region by extent o...

2016
Lili Feng Zhiqing Jia Qingxue Li

Aeolian desertification is poorly understood despite its importance for indicating environment change. Here we exploit Gaofen-1(GF-1) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to develop a quick and efficient method for large scale aeolian desertification dynamic monitoring in northern China. This method, which is based on Normalized Difference Desertification Index (NDDI) ...

2008
Q. CHANG

Integrating remote sensing (RS) with geographic information system (GIS), distribution digital maps of land desertification, spatial database and their statistics in the year of 1986, 1993 and 2000 were obtained by correcting, amplifying and auto classifying the RS images of interlaced zone for agriculture and animal husbandry in northern Shaanxi. The results showed that in the last 15 years de...

2016
Long Wan Jing Tong Jinxing Zhou Hongyan Guo Ming Cui Yuguo Liu Like Ning Fukai Tang

Over the past several decades, rocky desertification has led to severe ecological problems in karst areas in South China. After a rocky desertification treatment project was completed, the vegetation coverage changed greatly and, consequently, increased the ecology water consumption (approximately equal to the actual evapotranspiration) of the regional vegetation. Thus, it intensified the regio...

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