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The index is given as: = (+) (+ +) where L is a canopy background adjustment factor. An L value of 0.5 in reflectance space was found to minimize soil brightness variations and eliminate the need for additional calibration for different soils. The transformation was found to nearly eliminate soil-induced variations in vegetation indices. [1]
The normalized difference vegetation index (NDVI) is a widely-used metric for quantifying the health and density of vegetation using sensor data. It is calculated from spectrometric data at two specific bands: red and near-infrared.
6- monthly NDVI average for Australia, 1 Dec 2012 to 31 May 2013 [1]. A vegetation index (VI) is a spectral imaging transformation of two or more image bands designed to enhance the contribution of vegetation properties and allow reliable spatial and temporal inter-comparisons of terrestrial photosynthetic activity and canopy structural variations.
2011 Enhanced vegetation index based on MODIS Terra data. The enhanced vegetation index (EVI) is an 'optimized' vegetation index designed to enhance the vegetation signal with improved sensitivity in high biomass regions and improved vegetation monitoring through a de-coupling of the canopy background signal and a reduction in atmosphere influences.
Soil is dry for at least half of the growing season and moist for less than 90 consecutive days; common in arid (desert-like) regions. Xeric: Soil moisture regime is found in Mediterranean-type climates, with cool, moist winters and warm, dry summers. Like the Ustic Regime, it is characterized as having long periods of drought in the summer.
Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term vegetation. The vegetation type is defined by characteristic dominant species, or a common aspect of the assemblage, such as an elevation range or environmental ...
Indicator value is a term that is used in the ecology of plants for two different indices. The older usage of the term refers to Ellenberg's indicator values from 1974, which are based on a simple ordinal classification of plants according to the position of their realized ecological niche along an environmental gradient. [1]
Soil moisture regime is strongly influenced by position on a slope (Figure 3). Soil moisture and soil nutrient regimes are the two categorical axes used in an edatopic grid to characterize the generalized environmental conditions of vegetation units within a biogeoclimatic unit for most types of terrestrial ecosystems (see Figure 4 for an example).