نتایج جستجو برای: شاخص ndvi

تعداد نتایج: 79772  

2016
Jiaxin Jin Ying Wang Min Cheng Audrey L. Mayer

Intact Forest Landscape (IFL) is of great value in protecting biodiversity and supporting core ecological processes. It is important to analyze the spatial variation in the growth dynamics of IFL. This study analyzed the change of the Normalized Difference Vegetation Index (NDVI) during the growing season (April–October) for boreal (45 ̋ N–70 ̋ N) IFLs and the correlation with climatic variables ...

Journal: :Remote Sensing 2015
Haidong Li Yingkui Li Weishou Shen Yanan Li Jie Lin Xiaoyu Lu Xia Xu Jiang Jiang

The Yarlung Zangbo River basin is an important alley to transport moisture from the Indian Ocean to the inner Tibetan Plateau. With a wide range of elevations from 147 m to over 7000 m above sea level (a.s.l.), ecosystems respond differently to climate change at various elevations. However, the pattern of elevation-dependent vegetation change and how it responds to recent warming have been rare...

Journal: :Remote Sensing 2016
Ruoyu Wang Keith A. Cherkauer Laura C. Bowling

Corn growth conditions and yield are closely dependent on climate variability. Leaf growth, measured as the leaf area index, can be used to identify changes in crop growth in response to climate stress. This research was conducted to capture patterns of spatial and temporal corn leaf growth under climate stress for the St. Joseph River watershed, in northeastern Indiana. Leaf growth is represen...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده منابع طبیعی 1389

این مطالعه با هدف بررسی تغییرات تاج پوشش گیاهی در 4 مکان مرتعی در اطراف شهرستان سمیرم واقع در استان اصفهان و یک منطقه جنگلی در شهرستان لردگان از توابع استان چهار محال و بختیاری در دو دهه گذشته انجام شده است. برای این منظور تصاویر ماهواره لندست در 6 دوره زمانی سال های 1990، 1999، 2000، 2001، 2002 و 2009 و یک تصویر ماهواره irs-p6 (سنجنده awifs) مربوط به سال 2006 انتخاب و مورد پردازش قرار گرفت. اب...

بابک میرباقری عاشورلو داود علی اکبر متکان متین شهری

با توجه به اینکه کشاورزی یکی از پایه های اقتصادی کشور محسوب می شود، لذا برآورد مقدار تولید محصولات زراعی و باغی از اهمیت ویژه ای برخوردار است.  هدف از این تحقیق برآورد میزان  توده زنده گندم با استفاده از تصاویر ماهواره ایSPOTمی باشد. به این منظور از تصاویر ماهواره  SPOT در دو دوره زمانی رشد گیاه:زمان اوج سبزینگی و رسیدن مزارع برای برآورد سطح زیر کشت گندم در شهرستانهای همدان و بهار استفاده شد. پ...

Journal: :Remote Sensing 2016
Michael T. Schaefer David W. Lamb

The total biomass of a tall fescue (Festuca arundinacea var. Fletcher) pasture was assessed by using a vehicle mounted light detection and ranging (LiDAR) unit to derive canopy height and an active optical reflectance sensor to determine the spectro-optical reflectance index, normalized difference vegetation index (NDVI). In a random plot design, measurements of NDVI and pasture height were com...

2005
Marc B. Parlange

Monthly composites of the Normalized Difference Vegetation Indices (NDVI), derived from the National Oceanic and Atmospheric Administration's (NOAA) Advanced Very High Resolution Radiometer (AVILRR), were transformed linearly into monthly evaporation rates and compared with detailed hydrologic-model simulation results for five watersheds across the United States. Model-simulated monthly evapora...

Journal: :Ecology 2007
Nathalie Pettorelli Fanie Pelletier Achaz Von Hardenberg Marco Festa-Bianchet Steeve D Côté

Seasonal patterns of climate and vegetation growth are expected to be altered by global warming. In alpine environments, the reproduction of birds and mammals is tightly linked to seasonality; therefore such alterations may have strong repercussions on recruitment. We used the normalized difference vegetation index (NDVI), a satellite-based measurement that correlates strongly with aboveground ...

2003

Crop coefficients are a widely used and universally accepted method for estimating the crop evapotranspiration (ETc) component in irrigation scheduling programs. However, uncertainties of generalized basal crop coefficient (Kcb) curves can contribute to ETc estimates that are substantially different from actual ETc. Limited research with corn has shown improvements to irrigation scheduling due ...

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