نتایج جستجو برای: vegetation complexity

تعداد نتایج: 365840  

2008
Tsegaye Tadesse Brian D. Wardlow Jae H. Ryu

The temporal and spatial vegetation dynamics is highly dependent on many different environmental and biophysical factors. Among these, climate is one of the most important factors that influence the growth and condition of vegetation (Propastin et al., 2006). The complexity of the relationships between vegetation and climate; climate and oceanic dynamics; and the impacts of the combination of o...

2016
Rubina Parveen Subhash Kulkarni V. D. Mytri S. Bharathi V. Shreyas R. Anirudh S. Sanketh P. D. Shenoy K. Venugopal

Extraction of vegetation is an important step for agricultural, forest and greenery mapping. The proposed method examines the complex process of land cover vegetation pattern classification using an IRS-1C LISS III image. Pre-processing was done by employing partial differential equation (PDE). Normalized differential vegetation index (NDVI) was applied to separate vegetation features from the ...

2012
Fouzi Harrou Mohamed N. Nounou Hazem N. Nounou

Ozone is one of the most severe air pollution problems in the world. The concentration of ozone in the troposphere is of great interest because of its negative influence on the human health, vegetation and materials. The complexity of ozone (O3) formation mechanisms in the troposphere, the complexity of meteorological conditions in urban areas and the uncertainty in the measurements of all the ...

Gholamreza Zehtabian Hasan Ahmadi Hossein Azarnivand 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...

2017
Nannan Gao Jihua Zhou Xiaolong Zhang Wentao Cai Tianyu Guan Lianhe Jiang Hui Du Dawen Yang Zhentao Cong Yuanrun Zheng

Vegetation patterns and spatial organization are influenced by the changing environmental conditions and human activities. However, the effect of environment on vegetation at different vegetation classification levels has been unclear. We conducted an analysis to explore the relationship between environment and vegetation in the land use/land cover (LULC), vegetation group, vegetation type, and...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

identification of the best vegetation indices (vis) for use in quantitative analyzes of vegetation is one of the important issues for ecologists. the objective of this study was sensitivity evaluation of vegetation indices to a stand volume for identification of the best vegetation index (vi) in stand volume estimation using a statistical sensitivity method. also, another objective of this stud...

2008
Eric A. Davidson Gregory P. Asner Thomas A. Stone Christopher Neill Ricardo O. Figueiredo

[1] Degradation of cattle pastures is a management concern that influences future land use in Amazonia. However, ‘‘degradation’’ is poorly defined and has different meanings for ranchers, ecologists, and policy makers. Here we analyze pasture degradation using objective scalars of photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and exposed soil (S) derived from Landsat image...

1998
Christopher J. Kucharik John M. Norman Stith T. Gower

A new instrument called a Multiband Vegetation Imager (MVI) (Kucharik et al., 1997), which uses a 16-bit charge-coupled device (CCD) camera and ®lter exchange mechanism to capture 2-band (visible and near-infrared) image pairs of plant canopies, has been used to measure the light distribution over sunlit leaves and indirectly infer leaf area index (LAI), sunlit LAI and leaf angle distribution (...

Journal: :مرتع و آبخیزداری 0
محسن نقیلو کارشناس دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد جعفری استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد طهمورث 3 کارشناس ارشد آبخیزداری، ایران اصغر کهندل استادیار جهاد دانشگاهی واحد تهران، ایران فریناز همدانیان 5 فارغ التحصیل کارشناس ارشد مرتعداری، ایران

the purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. the study area is located in west of tehran province and southeast of hashtgerd, next to najm-abad village. after field studies, the index ...

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