نتایج جستجو برای: vegetation index
تعداد نتایج: 435690 فیلتر نتایج به سال:
estimation of vegetation cover attributes, such as the leaf area index (lai), is an important step in identifying the amount of water use for some plants. the goal of this study is to investigate the feasibility of using irs liss-iii data to retrieve lai. to get a lai retrieval model based on reflectance and vegetation index, detailed field data were collected in the study area of eastern iran....
Soil salinity undergoes significant spatial and temporal variations; therefore, salinity mapping is difficult, expensive, and time consuming. However, researchers have mainly focused on arid soils (bare) and less attention has been paid to halophyte plants and their role as salinity indicators. Accordingly, this paper aimed to investigate the relationship between soil properties, such as electr...
Rainfall, soil moisture, increasing temperature and changes in vegetation cover are the most important parameters effecting drought. Therefore, analysis of vegetation fraction and soil spectral signature, especially in red and infra red bands, are essential in drought estimation using remote sensing. In this study, Modified Perpendicular Drought Index (MPDI), which uses Vegetation Fraction (VF)...
The Normalized Difference Vegetation Index (NDVI) is widely used for Leaf Area Index (LAI) estimation. It is well documented that the NDVI is extremely subject to the saturation problem when LAI reaches a high value. A new multi-angular vegetation index, the Hotspot-darkspot Difference Vegetation Index (HDVI) is proposed to estimate the high density LAI. The HDVI, defined as the difference betw...
One of the consequences of drought, decline water resources, reduced agricultural production, changes in vegetation and accelerate the desertification areas in the assessment of the effects of drought on vegetation is of paramount importance. In this regard, the use of remote sensing and ground data to assess the effects of drought is the most efficient known methods.In this study, The effect o...
The leaf area index (LAI) is a key characteristic of forest ecosystems. Estimations of LAI from satellite images generally rely on spectral vegetation indices (SVIs) or radiative transfer model (RTM) inversions. We have developed a new and precise method suitable for practical application, consisting of building a species-specific SVI that is best-suited to both sensor and vegetation characteri...
The presence and continued existence of tidal morphologies, and in particular of salt marshes, is intimately connected with biological activity, especially with the presence of halophytic vegetation. Here, we review recent contributions to tidal biogeomorphology and identify the presence of multiple competing stable states arising from a two-way feedback between biomass productivity and topogra...
We continue investigation of the effect of position in announcements of newly received articles, a single day artifact, with citations received over the course of ensuing years. Earlier work [1, 2] focused on the " visibility " effect for positions near the beginnings of announcements, and on the " self-promotion " effect associated to authors intentionally aiming for these positions, with both...
in present study effects of riparian vegetation on morphometric and morphological changes have been investigated in a part of talar river during 58 years. so land use maps produced for 1955 and 2013 by aerial photos. results show during study time riparian vegetation changed extremely and approximately 96% of riparian vegetation removed during 58 years. in additionally, results showed during st...
the objective of this study is to develop a novel methodology integrating remote sensing, geographic information system technology and local spatial autocorrelation geo-computation for quick drought assessment. one group of drought indices, based on the condition of the vegetation, includes the normalized difference vegetation index (ndvi), anomaly of normalized difference vegetation index (ndv...
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