نتایج جستجو برای: آنومالی ndvi

تعداد نتایج: 6894  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم انسانی 1389

هدف این رساله مدل سازی و ارزیابی ارتباط وردایی عناصر اقلیمی با مقدار وردایی ndvi می باشد. به این منظور داده های بارش، دما و رطوبت نسبی (حداکثر، میانگین و حداقل) 141 ایستگاه هواشناسی و 1115 تصویر ماهوارهای noaa-avhrr، در دوره آماری 2006-1987 استفاده گردید. در این پژوهش ابتدا روش بهینه درون یابی عناصر اقلیمی تعیین گردید. بعد از تصحیح هندسی تصاویر و اعمال شاخص ndvi، ترکیب مقادیر حداکثر ماهانه استخ...

2007
P. E. DENNISON

Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were compared for monitoring live fuel moisture in a shrubland ecosystem. Both indices were calculated from 500 m spatial resolution Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance data covering a 33 month period from 2000 to 2002. Both NDVI and NDWI were positively correlated with live ...

2005
Felix Rembold Fabio Maselli

This current work is aimed at developing and testing a methodology which can be applied to low spatial resolution satellite data to assess inter-annual crop area variations on a regional scale. The methodology is based on the assumption that within mixed pixels, such variations are reflected by changes of the related multitemporal Normalised Difference Vegetation Index (NDVI) profiles. This imp...

Journal: :Remote Sensing 2015
Xianfeng Liu Xiufang Zhu Shuangshuang Li Yanxu Liu Yaozhong Pan

In recent decades, the monitoring of vegetation dynamics has become crucial because of its important role in terrestrial ecosystems. In this study, a satellite-derived normalized difference vegetation index (NDVI) was combined with climate factors to explore the spatiotemporal patterns of vegetation change during the growing season, as well as their driving forces in China from 2001 to 2012. Ou...

2002
Todd M. Scanlon John D. Albertson Kelly K. Caylor Chris A. Williams

Savanna ecosystems are water limited and responsive to rainfall on short time scales, characteristics that can be exploited to estimate fractional cover of trees, grass, and bare soil over large-scale areas from synthesis of remote sensing and rainfall measurements. A method is presented to estimate fractional cover based upon the differing ways in which grasses and trees respond to rainfall, a...

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...

2008
E. Swinnen

This study contributes to a better understanding of the spatial and temporal patterns of ecosystem dynamics in Southern Africa in response to climatic variability. First, we identified the areas where NDVI is covarying with precipitation, and where rainfall anomalies are correlated with NDVI anomalies. The results suggest that these correlations are related to quasi-periodicities in rainfall pa...

Journal: :Remote Sensing 2014
Stefan Erasmi Anne Schucknecht Marx P. Barbosa Jörg Matschullat

The spatio-temporal variability of trends in vegetation greenness in dryland areas is a well-documented phenomenon in remote sensing studies at global to regional scales. The underlying causes differ, however, and are often not well understood. Here, we analyzed the trends in vegetation greenness for a semi-arid area in northeastern Brazil (NEB) and examined the relationships between those dyna...

Journal: :Remote Sensing 2017
Wenjian Hua Haishan Chen Liming Zhou Zhenghui Xie Minhua Qin Xing Li Hedi Ma Qinghan Huang Shanlei Sun

This study attempts to quantify the relative contributions of vegetation greening in China due to climatic and human influences from multiple observational datasets. Satellite measured vegetation greenness, Normalized Difference Vegetation Index (NDVI), and relevant climate, land cover, and socioeconomic data since 1982 are analyzed using a multiple linear regression (MLR) method. A statistical...

2008
J. Dash T. Lankester S. Hubbard P. J. Curran

The Phenology of vegetation varies with climate and variability in phenology is a powerful measure of climate change. Remotely-sensed data can be used to produce phenology curves that capture ‘green-up’, maturity and senescence from local to global scales. These curves are usually produced with Normalised Difference Vegetation Index (NDVI) data but are notoriously noisy. The MERIS Terrestrial C...

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