نتایج جستجو برای: شاخص ndvi

تعداد نتایج: 79772  

Journal: :Remote Sensing 2015
Martha Raynolds Borgþór Magnússon Sigmar Metúsalemsson Sigurður H. Magnússon

In a greening Arctic, Iceland stands out as an area with very high increases in the AVHRR Normalized Difference Vegetation Index (NDVI, 1982–2010). We investigated the possible sources of this anomalous greening in Iceland’s dynamic landscape, analyzing changes due to volcanism and warming temperatures, and the effects of agricultural and industrial land use changes. The analysis showed the inc...

Journal: :Remote Sensing 2013
Feng Tian Yunjia Wang Rasmus Fensholt Kun Wang Li Zhang Yi Huang

The increasingly intensive and extensive coal mining activities on the Loess Plateau pose a threat to the fragile local ecosystems. Quantifying the effects of coal mining activities on environmental conditions is of great interest for restoring and managing the local ecosystems and resources. This paper generates dense NDVI (Normalized Difference Vegetation Index) time series between 2000 and 2...

2009
D A Walker M O Leibman

The causes of a greening trend detected in the Arctic using the normalized difference vegetation index (NDVI) are still poorly understood. Changes in NDVI are a result of multiple ecological and social factors that affect tundra net primary productivity. Here we use a 25 year time series of AVHRR-derived NDVI data (AVHRR: advanced very high resolution radiometer), climate analysis, a global geo...

2000
D. M. STOMS W. W. HARGROVE D. M. Stoms W. W. Hargrove

Baseline data are needed to determine the overall magnitude and direction of change in ecosystem functioning. This letter presents an approach to estimate potential NDVI fromenvironmental variables and training data of actual NDVI in nature reserves. Patterns of deviations of actual NDVI from the baseline generally correspond with land-use types in the western United States.

Journal: :Remote Sensing 2016
Helen B. Anderson Lennart Nilsen Hans Tømmervik Stein Rune Karlsen Shin Nagai Elisabeth J. Cooper

To remotely monitor vegetation at temporal and spatial resolutions unobtainable with satellite-based systems, near remote sensing systems must be employed. To this extent we used Normalized Difference Vegetation Index NDVI sensors and normal digital cameras to monitor the greenness of six different but common and widespread High Arctic plant species/groups (graminoid/Salix polaris; Cassiope tet...

ژورنال: جنگل ایران 2020

مطالعۀ روند تغییرات پوشش‌های گیاهی شهری با توجه به عملکردهای مختلف محیط زیستی، اجتماعی، فرهنگی و اقتصادی آنها به‌منظور مدیریت پایدار شهرها ضروری است. در این پژوهش به بررسی روند تغییرات سبزینگی پوشش گیاهی کلانشهر تهران با استفاده از شاخص تفاوت پوشش گیاهی نرمال‌شده (NDVI) حاصل از داده‌های ماهواره‌ای لندست‌های 5 و 8 در زمان حداکثر سبزینگی پوشش گیاهی با به‌کارگیری روش‌های پارامتری (رگرسیون حداقل مر...

حمیدرضا جدی ازغندی سعید ازادی قطار سیدکاظم علوی پناه, عبدالعلی رضایی,

چکیده        پدیده جزیره حرارتی شهری به­طور کلی به­وسیله یک کاهش در جریان گرمای نهان و یک افزایش در گرمای محسوس در مناطق شهری صورت می­گیرد. امروزه این پدیده یکی از معضلات عمده­ شهرهای بزرگ می­باشد، به­طوری که توجه بسیاری از محققان و متخصصان در رشته­های مختلف را به­خود جلب نموده است. در این تحقیق جزایر حرارتی شهر تهران که یکی از پرجمعیت­ترین شهرهای دنیا بوده و هر روزه بر جمعیت و ساخت و سازهای آن...

Journal: :Remote Sensing 2014
Gang Bao Zhihao Qin Yuhai Bao Yi Zhou Wenjuan Li Amarjargal Sanjjav

The response of vegetation to regional climate change was quantified between 1982 and 2010 in the Mongolian plateau by integrating the Advanced Very High Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI) (1982–2006) and the Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI (2000–2010). Average NDVI values f...

2002
R. B. Myneni D. L. Williams

T e influence of pixel heterogeneity, background, atmospheric and bidirectional effects on the relationship between fraction of photosynthetically active radiation absorbed by the photosynthesizing tissue in a canopy (FAPAR) and normalized difference vegetation index (NDVI) is investigated using a three-dimensional model of radiation transfer. Top of the canopy (TOC) NDVI and FAPAR increase wit...

2017
Jinting Guo Yuanman Hu Zaiping Xiong Xiaolu Yan Chunlin Li

Permafrost is extremely sensitive to climate change. The degradation of permafrost has strong and profound effects on vegetation. The permafrost zone of northeastern China is the second largest region of permafrost in China and lies on the south edge of the Eurasian cryolithozone. This study analyzed the spatiotemporal variations of the growing-season Normalization Difference Vegetation Index (...

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