نتایج جستجو برای: داده های ndvi

تعداد نتایج: 523517  

2008
David Verbyla D. Verbyla

Aim To examine the trends of 1982–2003 satellite-derived normalized difference vegetation index (NDVI) values at several spatial scales within tundra and boreal forest areas of Alaska. Location Arctic and subarctic Alaska. Methods Annual maximum NDVI data from the twice monthly Global Inventory Modelling and Mapping Studies (GIMMS) NDVI 1982–2003 data set with 64-km 2 pixels were extracted from...

2009
Bhushan Gokhale

Understanding the distribution of landscape variables presents several advantages to researchers focusing on ecological studies. The Normalized Difference Vegetation Index (NDVI) is a relatively common productivity variable used to assess, monitor, and compare landscapes. In this study, an NDVI layer was created using Satellite Pour l'Observation de la Terre 4 (SPOT 4) satellite imagery to comp...

2007
C G Marston R P Armitage F M Danson P Giraudoux A Ramirez P S Craig

This work modelled the spatial distribution of the rodent species that act as hosts in the transmission cycle of the parasitic tapeworm Echinococcus multilocularis. The rodent distribution was modelled in relation to landscape characteristics in four ways, using (1) a Landsat ETM+ derived hard classification, (2) single-image Landsat ETM+ derived NDVI, (3) single-image MODIS 16-day composite ND...

ژورنال: انسان و محیط زیست 2018

کوهستان شیرکوه در استان یزد به وسیله نواحی گرم و خشک احاطه شده است. این کوهستان سردترین مناطق استان را به خود اختصاص داده است. موقعیت جغرافیایی این منطقه سبب شده که اکوسیستم آن بسیار حساس بوده و پوشش گیاهی نقش به سزایی در آب و هوا و معیشت مردم داشته باشد. در مطالعه حاضر جهت بررسی تغییرات اقلیمی از تصاویر ماهواره­ای، تکنولوژی سنجش از دور و سامانه اطلاعات جغرافیایی استفاده شد.  در این راستا با ا...

2000
J. WANG P. M. RICH K. P. PRICE J. Wang

Normalized Difference Vegetation Index (NDVI) is generally recognized as a good indicator of terrestrial vegetation productivity. Understanding climatic influences, in particular precipitation and temperature, on NDVI enables prediction of productivity changes under different climatic scenarios. We examined temporal responses of remotely sensed NDVI to precipitation and temperature during a nin...

2017
Xiaoyi Guo Hongyan Zhang Zhengfang Wu Jianjun Zhao Zhengxiang Zhang

Time series of Normalized Difference Vegetation Index (NDVI) derived from multiple satellite sensors are crucial data to study vegetation dynamics. The Land Long Term Data Record Version 4 (LTDR V4) NDVI dataset was recently released at a 0.05 × 0.05° spatial resolution and daily temporal resolution. In this study, annual NDVI time series that are composited by the LTDR V4 and Moderate Resoluti...

2008
AJAY NARENDRA

This study in Western Ghats, India, investigates the relation between nesting sites of ants and a single remotely sensed variable: the Normalised Difference Vegetation Index (NDVI). We carried out sampling in 60 plots each measuring 30 x 30 m and recorded nest sites of 13 ant species. We found that NDVI values at the nesting sites varied considerably between individual species and also between ...

2013
GAN Wenxia SHEN Huanfeng ZHANG Liangpei GONG Wei

Medium Resolution NDVI( Normalized Difference Vegetation Index) from different sensor systems such as Landsat, SPOT, ASTER, CBERS and HJ-1A/1B satellites provide detailed spatial information for studies of ecosystems, vegetation biophysics, and land cover. Limitation of sensor designs, cloud contamination, and sensor failure highlighted the need to normalize and integrate NDVI from multiple sen...

1997
Zhengming Wan

The global land-surface temperature (LST) and normalized difference vegetation index (NDVI) products retrieved fromModerate Resolution Imaging Spectroradiometer (MODIS) data in 2001 were used in this study. The yearly peak valuesof NDVI data at 5km grids were used to define six NDVI peak zones from -0.2 to 1 in steps of 0.2, and the monthlyNDVI values at each grid were sorted in dec...

2008
Juan Gu Xin Li Chunlin Huang

Consistent Normalized Difference of Vegetation Index (NDVI) time series, as paramount and powerful tool, can be used to monitor ecological resources that are being altered by climate and human impacts, since its temporal evolution is strongly linked to changes in the state of land surface. However, the noise caused mainly by cloud contamination, heavy aerosol, atmospheric variability and signal...

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