نتایج جستجو برای: شاخص تفاضل بههنجارشده پوششگیاهی ndvi

تعداد نتایج: 81918  

2004
G. J. JIA H. E. EPSTEIN D. A. WALKER

We analysed the Normalized Difference Vegetation Index (NDVI), calculated from biweekly NOAA Advanced Very High Resolution Radiometer (AVHRR) images for northern Alaska at both regional (latitudinal gradients) and site scales. Our objectives were to determine if tundra types and arctic subzones could be differentiated in terms of intra-seasonal patterns of greenness, and to construct the relati...

2003
D. O. FULLER M. FULK

Fire scars in Kalimantan, Indonesia were mapped using optical and thermal data from the NOAA-AVHRR satellite sensor. Forty-four high-resolution picture transmission images mapped at 1 km spatial resolution were selected for a period immediately after intense biomass burning from October–December 1997. Composite images of the Normalized DiŒerence Vegetation Index (NDVI), surface temperature (ST)...

2009
Carlos M. Di Bella Ignacio J. Negri Gabriela Posse Florencia R. Jaimes Esteban G. Jobbágy Martin F. Garbulsky Victor A. Deregibus

Information about forage productivity and its interactions with cultural practices or climatic variation is necessary to plan livestock management and to increase production without damaging the environment. Remote sensing provides a valuable data source to achieve these goals. Here we characterize forage production over a large region (92 million hectares) by analyzing spatial, seasonal, and i...

2016
Lijuan Wang Guimin Zhang Hui Lin Liang Liang Zheng Niu

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...

2010
Angélica Giarolla Yosio E. Shimabukuro José dos Campos

This study aimed to evaluate the response of the Normalized Difference Vegetation Index NDVI derived from Terra MODIS sensor to soybean phenology, in a grain producer region of Parana State, Brazil. Landsat TM and ETM+ images were selected to analyze the spatial distribution of soybean fields for this region from 2000/01 to 2006/07 crop seasons. Then pure pixel samples (250 x 250m) that contain...

Journal: :The American naturalist 2003
Allen H Hurlbert John P Haskell

We analyzed geographic patterns of richness in both the breeding and winter season in relation to a remotely sensed index of seasonal production (normalized difference vegetation index [NDVI]) and to measures of habitat heterogeneity at four different spatial resolutions. The relationship between avian richness and NDVI was consistent between seasons, suggesting that the way in which available ...

2012
LI Peng FENG Zhiming LIU Yujie XIAO Xiangming

Rice cropping systems not only characterize comprehensive utilization intensity of agricultural resources but also serve as the basis to enhance the provision services of agro-ecosystems. Yet, it is always affected by external factors, like agricultural policies. Since 2004, seven consecutive No.1 Central Documents issued by the Central Government have focused on agricultural development in Chi...

Journal: :IEEE Trans. Geoscience and Remote Sensing 2000
Robert K. Kaufmann Liming Zhou Yuri Knyazikhin Nikolay V. Shabanov Ranga B. Myneni Compton J. Tucker

This paper assesses the effect of changes in solar zenith angle (SZA) and sensor changes on reflectances in channel 1, channel 2, and normalized difference vegetation index (NDVI) from the advanced very high resolution radiometer (AVHRR) Pathfinder land data set for the period July 1981 through September 1994. First, the effect of changes in SZA on channel reflectances and NDVI is derived from ...

Journal: :Remote Sensing 2015
Ya Liu Yan Li Shuangcheng Li Safa Motesharrei

Changes in vegetation activity are driven by multiple natural and anthropogenic factors, which can be reflected by Normalized Difference Vegetation Index (NDVI) derived from satellites. In this paper, NDVI trends from 1982 to 2012 are first estimated by the Theil–Sen median slope method to explore their spatial and temporal patterns. Then, the impact of climate variables and human activity on t...

2010
Domingo Alcaraz-Segura Elisa Liras Siham Tabik José M. Paruelo Javier Cabello

Successive efforts have processed the Advanced Very High Resolution Radiometer (AVHRR) sensor archive to produce Normalized Difference Vegetation Index (NDVI) datasets (i.e., PAL, FASIR, GIMMS, and LTDR) under different corrections and processing schemes. Since NDVI datasets are used to evaluate carbon gains, differences among them may affect nations' carbon budgets in meeting international tar...

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