نتایج جستجو برای: تفاضل ndvi

تعداد نتایج: 8128  

Journal: :Remote Sensing 2016
Ran Wang John A. Gamon Rebecca A. Montgomery Philip A. Townsend Arthur I. Zygielbaum Keren Bitan David Tilman Jeannine Cavender-Bares

Species richness generally promotes ecosystem productivity, although the shape of the relationship varies and remains the subject of debate. One reason for this uncertainty lies in the multitude of methodological approaches to sampling biodiversity and productivity, some of which can be subjective. Remote sensing offers new, objective ways of assessing productivity and biodiversity. In this stu...

Journal: :Mathematical and Computer Modelling 2011
Yujian Yang Jianhua Zhu Chunjiang Zhao Shuyun Liu Xueqin Tong

Under the framework of the soil–wheat system, the sampling area was selected in the demonstration site of Lingxian country of Shandong province, Normalized Difference Vegetation Index (NDVI) of 195 sites were collected by GreenSeeker optical sensor based on the GPS localization data. The main objective of the paper developed the comparison study by Kriging and BPNN algorithm for NDVI continuity...

2010
Stephanie Pau Gregory S. Okin Thomas W. Gillespie

The Hawaiian Islands are an ideal location to study the response of tropical forests to climate variability because of their extreme isolation in the middle of the Pacific, which makes them especially sensitive to El Niño-Southern Oscillation (ENSO). Most research examining the response of tropical forests to drought or El Niño have focused on rainforests, however, tropical dry forests cover a ...

2011
Mary Elizabeth Parent

Vegetation health can be monitored using a time series of remotely sensed images by calculating the Normalized Difference Vegetation Index (NDVI). We assessed temporal trends throughout an NDVI time series with three sensors: Advanced Very High Resolution Radiometer (AVHRR), the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat Thematic Mapper/Enhanced Thematic Mapper Plus (TM/E...

2005
Sebastian M. Riedel Howard E. Epstein Donald A. Walker David L. Richardson Monika P. Calef Amber Moody

Intraseasonal patterns of normalized difference vegetation index (NDVI), leaf area index (LAI), and phytomass were compared for four tundra vegetation types at Ivotuk, Alaska, during summer 1999. The vegetation types included moist acidic tundra (MAT), moist nonacidic tundra (MNT), mossy tussock tundra, and shrub tundra. The seasonal curves of NDVI were similar among the vegetation types but wi...

Journal: :Remote Sensing 2015
David Helman Itamar M. Lensky Naama Tessler Yagil Osem

We present an efficient method for monitoring woody (i.e., evergreen) and herbaceous (i.e., ephemeral) vegetation in Mediterranean forests at a sub pixel scale from Normalized Difference Vegetation Index (NDVI) time series derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The method is based on the distinct development periods of those vegetation components. In the dry sea...

2013
Hone-Jay Chu Chun-Yu Liu Chi-Kuei Wang

The effects on water quality of land use and land cover changes, which are associated with human activities and natural factors, are poorly identified. Fine resolution satellite imagery provides opportunities for land cover monitoring and assessment. The multiple satellite images after typhoon events collected from 2001 to 2010 covering land areas and land cover conditions are evaluated by the...

Journal: :Remote Sensing 2017
Maria Lumbierres Pablo F. Méndez Javier Bustamante Ramón Soriguer Luis Santamaría

Plant primary production is a key driver of several ecosystem functions in seasonal marshes, such as water purification and secondary production by wildlife and domestic animals. Knowledge of the spatio-temporal dynamics of biomass production is therefore essential for the management of resources—particularly in seasonal wetlands with variable flooding regimes. We propose a method to estimate s...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Geli Zhang Jinwei Dong Yangjian Zhang Xiangming Xiao

We appreciate the comments on our article (1) from Shen et al. (2). They raise the issue of whether the nongrowing season (NGS) Normalized Difference Vegetation Index (NDVI) could affect spring phenology as interpreted from time series NDVI data. To address it, they compared the NGS NDVIs of two separate periods (1998–2000 and 2009–2011) and found a higher 2009–2011 NGS NDVI than that of 1998–2...

2013
Javed Iqbal John J. Read Frank D. Whisler

This field crop research study addresses the potential of image based remote sensing to provide spatially and temporally distributed information on timely basis for site-specific cotton crop management. Universal applicability of site specific crop management is hampered by lack of timely distributed and economically feasible information on soils and crop conditions in the field and their inter...

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