نتایج جستجو برای: Vegetation index

تعداد نتایج: 435690  

Journal: :pollution 2015
somayyeh jabbari seyed jamaledin khajedin reza jafari saeed soltani

to determine the suitable indices for vegetation cover and production assessment based on the remote sensing data, simultaneous digital data with field data belonging to the spring rangeland of the semirom-isfahan province were analyzed. during two years of monitoring the annual, grass, forb, and shrub vegetation cover and the total production data from 86 were collected. the global positioning...

Forest ecosystems are among the largest terrestrial carbon reservoirs on our planet earth thus playing a vital role in global carbon cycle. Presently, remote sensing techniques provide proper estimates of forest biomass and quantify carbon stocks. The present study has explored Landsat-8 sensor product and evaluated its application in biomass mapping and estimation. The specific objectives were...

Journal: :ecopersia 2015
davoud akhzari sahel haghighi

there are many reports of serious problems of dust storm events in the western parts of iran. based on many researches, iraq is one of the main sources of dust storms in western parts of iran. the radial basis function network (rbfn) model has been used to assess wind erosion hazard in iraq as a main source area of dust storms over several western cities of iran. the percentage of vegetation is...

Journal: :journal of rangeland science 2013
gholamreza zehtabian hossein azarnivand hasan ahmadi saeideh kalantari

one of the influential tools concerning the rangeland and vegetation sciences isthe technology of remote sensing and satellite data. satellite data have played essentialroles in preparing the needed information for studying the vegetation. vegetation has beenwidely recognized as one of the best indicators for determining the land conditions. usingvegetation indices is one of the techniques of r...

2012
Farooq Ahmad

To enhance the vegetation signal in remotely sensed data and provide an approximate measure of live green vegetation, a number of spectral vegetation indices have been developed to estimate biophysical parameters of vegetation. The sensitivity of the normalized difference vegetation index (NDVI) to the soil background and atmospheric effects has generated an increasing interest in the developme...

2014
Hongrui Ren Guangsheng Zhou

Accurate estimation of green aboveground biomass in arid and semiarid grassland is essential for a variety of studies, such as sustainable grassland management, fire risk assessment, climate change, and environmental degradation. A great need exists for the establishment of robust method for estimating green aboveground biomass in arid and semiarid grassland due to the influences of soil backgr...

Journal: :journal of rangeland science 2013
mahnoosh pourhadi saeed mohtashamnia mohammad mahdavi

ecotones are zones of gradual changes from an ecological system to another.ecotones monitoring could be important to find out the reason for changes and limits. inthis research satellite data were used to analyze the ecotone boundary in fars steppicrangelands using irs liss iii and pan data of year 2006. the real vegetation map andecotones prepared through geo-eye images from google earth softw...

2003
Cem Ünsalan Kim L. Boyer

Vegetation indices have been used extensively to estimate the vegetation density from satellite and airborne images for many years. In this paper we first focus on one of the most popular vegetation indices, the normalized difference vegetation index (NDVI ) [1] and introduce a statistical framework to analyze it. We propose a solution to the saturation problem of this index based on our statis...

2014
Gaolong Zhu Weimin Ju J. M. Chen Yibo Liu

A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different backgro...

Journal: :Remote Sensing 2014
Weicheng Wu

A large number of vegetation indices have been developed and widely applied in terrestrial ecosystem research in the recent decades. However, a certain limitation was observed while applying these indices in research in dry areas due to their low sensitivity to low vegetation cover. In this context, the objectives of this study are to develop a new vegetation index, namely, the Generalized Diff...

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