نتایج جستجو برای: vegetation indices

تعداد نتایج: 127108  

Journal: :Journal of economic entomology 2008
Matthew W Carroll John A Glaser Richard L Hellmich Thomas E Hunt Thomas W Sappington Dennis Calvin Ken Copenhaver John Fridgen

Eleven spectral vegetation indices that emphasize foliar plant pigments were calculated using airborne hyperspectral imagery and evaluated in 2004 and 2005 for their ability to detect experimental plots of corn manually inoculated with Ostrinia nubilalis (Hübner) neonate larvae. Manual inoculations were timed to simulate infestation of corn, Zea mays L., by first and second flights of adult O. ...

Abandonment of arable lands is the starting point of vegetation succession. The trajectory and speed of succession can be different according to the time of abandonment. The aim of this study is to assess the effect of abandonment periods on species richness, diversity and functional groups in shrublands and grasslands of Shirmard rangelands in Chaharmahal va Bakhtiri, Iran. A total of 96 abond...

Biodiversity is one of the important concepts in ecology and vegetation management, and plays an important role in the health, production, and evaluation of ecosystems. Species diversity is a major part of biodiversity and one of the most important parameters of ecosystem changes. In this research, the data of the rangeland evaluation different climate zones of Isfahan province were used in fiv...

2006
J. Verbesselt B. Somers J. van Aardt I. Jonckheere P. Coppin

This paper evaluated the capacity of SPOT VEGETATION time-series to monitor the vegetation biomass and water content in order to improve fire risk assessment in the savanna ecosystem of Kruger National Park in South Africa. First, the single date and integrated vegetation index approach, which quantify the amount of herbaceous biomass at the end of the rain season, were evaluated using in situ ...

2007
A. Lobo P. Henry M. Hafeez

The modelling of water and energy exchanges between Soil-Vegetation and the ATmosphere (SVAT) often assimilates remotely sensed time series of Vegetation Indices (VIs). At first order, spectral combinations like the Normalized Difference Vegetation Index (NDVI) are known for their ability to witness the geographic and seasonal distribution of greenness on continental surfaces. Another usual com...

2003
Michael D. Steven Timothy J. Malthus Frédéric Baret Hui Xu Mark J. Chopping

Spectroradiometric measurements were made over a range of crop canopy densities, soil backgrounds and foliage colour. The reflected spectral radiances were convoluted with the spectral response functions of a range of satellite instruments to simulate their responses. When Normalised Difference Vegetation Indices (NDVI) from the different instruments were compared, they varied by a few percent,...

Journal: :Remote Sensing 2014
Quanzhou Yu Shaoqiang Wang Robert A. Mickler Kun Huang Lei Zhou Huimin Yan Diecong Chen Shijie Han

Developments in hyperspectral remote sensing techniques during the last decade have enabled the use of narrowband indices to evaluate the role of forest ecosystem variables in estimating carbon (C) fluxes. In this study, narrowband bio-indicators derived from EO1 Hyperion data were investigated to determine whether they could capture the temporal variation and estimate the spatial variability o...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2013
Saeid Hamzeh Abd Ali Naseri Seyed Kazem Alavipanah B. Mojaradi Harm M. Bartholomeus Jan G. P. W. Clevers M. Behzad

The presence of salt in the soil profile negatively affects the growth and development of vegetation. As a result, the spectral reflectance of vegetation canopies varies for different salinity levels. This research was conducted to (1) investigate the capability of satellite-based hyperspectral vegetation indices (VIs) for estimating soil salinity in agricultural fields, (2) evaluate the perfor...

Journal: :Remote Sensing 2014
Julia Tüshaus Olena Dubovyk Asia Khamzina Gunter Menz

Accurate monitoring of land surface dynamics using remote sensing is essential for the synoptic assessment of environmental change. We assessed a Medium Resolution Imaging Spectrometer (MERIS) full resolution dataset for vegetation monitoring as an alternative to the more commonly used Moderate-Resolution Imaging Spectroradiometer (MODIS) data. Time series of vegetation indices calculated from ...

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