نتایج جستجو برای: تفاضل ndvi

تعداد نتایج: 8128  

2011
Shushi Peng Anping Chen Liang Xu Chunxiang Cao Jingyun Fang Ranga B Myneni Jorge E Pinzon Compton J Tucker Shilong Piao

Using satellite-derived normalized difference vegetation index (NDVI) data, several previous studies have indicated that vegetation growth significantly increased in most areas of China during the period 1982–99. In this letter, we extended the study period to 2010. We found that at the national scale the growing season (April–October) NDVI significantly increased by 0.0007 yr−1 from 1982 to 20...

دمای سطح زمین یکی از پارامترهای مهم برای تعیین بیلان انرژی زمین، مطالعات هواشناسی و محیطی است. از طرفی رشد سریع جمعیت، توسعه شهرها، پدیده آلودگی محیط‌زیست، تغییر شرایط آب و هوایی، پدیده وارونگی هوا ازیک‌طرف و فعالیت‌های زیست‌محیطی مانند ایجاد فضای سبز از طرف دیگر جمله عواملی هستند که بر کیفیت محیط‌زیست انسان تأثیر می‌گذارند. دمای هوا و دمای سطحی زمین شاخص‌هایی هستند که اهمیت آن‌ها رو به افزایش ...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2014
Bernt Johansen Hans Tømmervik

Several studies have shown a close relationship between vegetation fertility and different vegetation indices extracted from satellite data. The vegetation fertility in Arctic is at overall scales highly related to temperature. At lower scales surface material, snow cover, hydrology and anthropogenic effects (geese, reindeer) are determinant in constituting the different vegetation communities....

حجت اله یزدانپناه, حجت حسینقلی‌نژاد دزفولی سعید موحدی, مریم سلیمانی تبار مهدی مومنی

نیمه شمالی استان خوزستان گوشه ای از مناطق خشک و نیمه خشک کشور ایران به شمار می آید که به دلیل این ویژگی دائماً تحت تأثیر نوسانات کوچک وبزرگ نزولات جوی است.در این پژوهش از یک سری دادهای ماهواره ای ویک سری دادهای بارش ماهیانه ایستگاهی استفاده شده است،دادهای ماهواره ای متعلق به سنجنده MODIS ودادهای زمینی متعلق به 13 ایستگاه سینوپتیکی وکلیماتولوژی منطقه مطالعاتی است.درکار صورت گرفته ابتدا شاخص تفاضل...

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 ...

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