نتایج جستجو برای: different vegetation

تعداد نتایج: 1800636  

2008
M. Neubert S. Kropp S. Wagenknecht D. Stow

Fire risk is a major threat to life, property and natural resources in southern California. Recent fire disasters occurred in autumn 2003 and 2007. Fire risk management deals with these hazards, input data are collected, analyzed and evaluated. One of the most important input data is the vegetation density in the endangered areas. Here we describe methods to map vegetation density forming five ...

Journal: :Environmental Management 2007
Gregor T. Auble Patrick B. Shafroth Michael L. Scott James E. Roelle

The 4-year drawdown of Horsetooth Reservoir, Colorado, for dam maintenance, provides a case study analog of vegetation response on sediment that might be exposed from removal of a tall dam. Early vegetation recovery on the exposed reservoir bottom was a combination of (1) vegetation colonization on bare, moist substrates typical of riparian zones and reservoir sediment of shallow dams and (2) a...

2008
Zhengwei Yang Patrick Willis Rick Mueller

Multispectral satellite images have been utilized in the National Agricultural Statistics Service (NASS) for crop cover classification and crop acreage estimation since the 1970's. Though ancillary data is utilized to enhance the classification accuracy, there are few applications that maximize the utilization of the feature information of the given multispectral images. Every multispectral ima...

Journal: :Remote Sensing 2012
He Yin Thomas Udelhoven Rasmus Fensholt Dirk Pflugmacher Patrick Hostert

Detailed information from global remote sensing has greatly advanced our understanding of Earth as a system in general and of agricultural processes in particular. Vegetation monitoring with global remote sensing systems over long time periods is critical to gain a better understanding of processes related to agricultural change over long time periods. This specifically relates to sub-humid to ...

2016
Haixin Liu Anbing Zhang Tao Jiang Haitao Lv Xinxia Liu Hefeng Wang

This study proposes a modified vegetation-dependent temperature-vegetation dryness index (TVDI) model for analyzing regional drought disasters in the Beijing-Tianjin-Hebei Metropolitan Region (BTHMR) of China. First, MODIS monthly normalized difference vegetation index (NDVI), land surface temperature (LST) data and land use/cover data (Land cover type2) were pre-processed as a consistent big d...

2008
Luc Arnold François-Marie Bréon Simon Brewer

The so-called Vegetation Red-Edge (VRE), a sharp increase in the reflectance around 700 nm, is a characteristic of vegetation spectra, and can therefore be used as a biomarker if it can be detected in an unresolved extrasolar Earth-like planet integrated reflectance spectrum. Here we investigate the potential for detection of vegetation spectra during the last Quaternary climatic extrema, the L...

2013
Xinfeng Yao Xia Yao Wenqing Jia Yongchao Tian Jun Ni Weixing Cao Yan Zhu

Various sensors have been used to obtain the canopy spectral reflectance for monitoring above-ground plant nitrogen (N) uptake in winter wheat. Comparison and intercalibration of spectral reflectance and vegetation indices derived from different sensors are important for multi-sensor data fusion and utilization. In this study, the spectral reflectance and its derived vegetation indices from thr...

2006
A. KARNIELI M. BAYASGALAN Jacob Blaustein

The Vegetation Health index (VHI) is based on a combination of products extracted from vegetation signals, namely the Normalized Difference Vegetation Index (NDVI) and from the brightness temperatures, both derived from the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor. VH users rely on a strong inverse correlation between NDVI and land surface temperature, since increasing land ...

2015
Ryan J. Kramer Ping Zhang Robert E. Wolfe Thomas G. Huntington Marc L. Imhoff Kurtis Thome Genevieve L. Noyce Matthew McCabe

Most models evaluated by the Intergovernmental Panel for Climate change estimate projected increases in temperature and precipitation with rising atmospheric CO2 levels. Researchers have suggested that increases in CO2 and associated increases in temperature and precipitation may stimulate vegetation growth and increase evapotranspiration (ET), which acts as a cooling mechanism, and on a global...

2013
C Eisfelder I Klein J Huth M Niklaus C Kuenzer

Monitoring of net primary productivity (NPP) is especially important for the fragile ecosystems in arid and semi-arid regions. Great interest exists in observing large-scale vegetation dynamics and understanding spatial and temporal patterns of NPP in these areas. In this study we present results of NPP obtained with the model BETHY/DLR for Kazakhstan for 2003-2011 and its spatial and temporal ...

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