نتایج جستجو برای: vegetation indices

تعداد نتایج: 127108  

2002
A. Huete K. Didan T. Miura E. P. Rodriguez X. Gao L. G. Ferreira

We evaluated the initial 12 months of vegetation index product availability from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Earth Observing System-Terra platform. Two MODIS vegetation indices (VI), the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI), are produced at 1-km and 500-m resolutions and 16-day compositing periods. This pape...

Drought is a major problematic phenomenon mostly for semi-arid areas of Iran. During drought periods, reduction in vegetation levels causes such problems as soil erosion, surface runoff, flood risk, etc. Therefore, the assessment of drought effects on plant covers is the most important issue. This research was conducted in 2015 using the extracted vegetation indices from Moderate Resolution Ima...

2017
Mallory L Barnes David D Breshears Darin J Law Willem J D van Leeuwen Russell K Monson Alec C Fojtik Greg A Barron-Gafford David J P Moore

Earth's future carbon balance and regional carbon exchange dynamics are inextricably linked to plant photosynthesis. Spectral vegetation indices are widely used as proxies for vegetation greenness and to estimate state variables such as vegetation cover and leaf area index. However, the capacity of green leaves to take up carbon can change throughout the season. We quantify photosynthetic capac...

Journal: :The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 2019

2010
M. Ebrahimi A. A. Matkan

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)...

Journal: :The Science of the total environment 2003
D J Eldridge T B Koen

We examined changes in rangeland health in the semi-arid woodlands of eastern Australia at fixed sites between 1989 and 1999. Over the 11-year period there were significant declines in the quality of the vegetation, and changes in plant species were driven largely by seasonality, and to a lesser extent, amount of rainfall. Three indices of rangelands health (composition, function and stability)...

Journal: :Remote Sensing 2017
Thierry Erudel Sophie Fabre Thomas Houet Florence Mazier Xavier Briottet

This study aims to evaluate three classes of methods to discriminate between 13 peatland vegetation types using reflectance data. These vegetation types were empirically defined according to their composition, strata and biodiversity richness. On one hand, it is assumed that the same vegetation type spectral signatures have similarities. Consequently, they can be compared to a reference spectra...

2017
Kent A. Fricke

Small mammals can be an important bioindicator of ecosystem health. They serve as both predator and prey in many ecosystems. By means of live trapping and nest monitoring, we studied the ecological relationships between small mammals, avian nest survival, and vegetation composition and structure on six private ranches in the Sandhills of Nebraska during 2004. Our study documented six species (1...

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