نتایج جستجو برای: vegetation

تعداد نتایج: 47633  

2013
Fazel Amiri Abdul Rashid B. Mohamed Shariff

To determine suitable indices for vegetation cover and production assessment based on remote sensing data, simultaneous digital data with field data belonged to summer rangeland of southern part of Isfahan province were analyzed. During 2 years of monitoring, annuals, grasses, forbs and shrubs vegetation cover and total production data from sixty 1 square meter plots in each site were collected...

2008
Anning SUO Yong LIN Xiaojun KOU

Located in the central Chinese Loess Plateau, the Jinghe River is one of the major tributaries of the Yellow River, and the river basin it inhabits is characterized by a continental climate. Considering that land degradation has been the main ecological problem in the Jinghe River Basin, there is an urgent need to scientifically explore the land degradation mechanism in order to restore natural...

2017
Xiuxia Zhang Yaowen Xie

Given its proximity to an artificial oasis, the Donghu Nature Reserve in the Dunhuang Oasis has faced environmental pressure and vegetation disturbances in recent decades. Satellite vegetation indices (VIs) can be used to detect such changes in vegetation if the satellite images are calibrated to surface reflectance (SR) values. The aim of this study was to select a suitable VI based on the Lan...

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...

2011
S. M. Saunders E. Dade K. Van Niel

Managing vegetation in urban environments requires an understanding of its structure, atmospheric interactions and function. This has led to quantification and development of models to estimate the functions of urban vegetation, particularly the integrated effects that take place between vegetation and local atmospheres. The Urban FORest Effects (UFORE) model (developed in North America by the ...

ژورنال: مرتع و آبخیزداری 2012

Assessment process of vegetation cover by remote-sensing images should be based on understanding of the vegetation indices. Vegetation indices are widely used for assessing and monitoring ecological variables such as vegetation cover, above-ground biomass and leaf area index. The aim of the present research was to study of the ASTER data capabilities to estimate the vegetation cover percentage ...

Vegetation indices have been developed to characterize and extract the Earth's vegetation cover from space using satellite images. For detection of vegetation changes, usually temporal images are independently analyzed or vegetation index differencing is implemented. A review on previous studies reveal that, in spite of developing several vegetation indices, to extract vegetation cover or veget...

Journal: :Remote Sensing 2015
Xiaoyi Guo Hongyan Zhang Tao Yuan Jianjun Zhao Zhenshan Xue

Vegetation is an important part of terrestrial ecosystems. Although vegetation dynamics have explicit spatial and temporal dimensions, the study of the temporal process is in its infancy. Evaluation of temporal scaling behavior could provide a unique perspective for exploring the temporal nature of vegetation dynamics. In this study, the Global Inventory Modeling and Mapping Studies (GIMMS) Nor...

2014
Antonius G. T. Schut Grant W. Wardell-Johnson Colin J. Yates Gunnar Keppel Ireneusz Baran Steven E. Franklin Stephen D. Hopper Kimberley P. Van Niel Ladislav Mucina Margaret Byrne

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning ...

ژورنال: مرتع 2021

Drought as a complex ecosystem crisis can affect vegetation density and health. Iran with an arid and semi-arid climate is exposed to this phenomenon. Therefore, it is necessary to evaluate the effect of drought on vegetation. The purpose of this study is to evaluate the effect of meteorological drought on vegetation dynamics in Iran. In this regard, using MATLAB software, SPEI index with time ...

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