نتایج جستجو برای: vegetation index

تعداد نتایج: 435690  

2013
Kenta Obata Alfredo R. Huete

Multi-sensor analysis for monitoring terrestrial vegetation suffers from systematic errors due to the differences in spatial resolution, called scaling effect. This study investigates mechanisms underlying the scaling effect on fraction of vegetation cover (FVC) estimation, derived using a two-band spectral vegetation index (VI)-isoline based linear mixture model (VI-isoline based LMM). The two...

Journal: :Remote Sensing 2014
Lennert Schepers Birgen Haest Sander Veraverbeke Toon Spanhove Jeroen Vanden Borre Rudi Goossens

Uncontrolled, large fires are a major threat to the biodiversity of protected heath landscapes. The severity of the fire is an important factor influencing vegetation recovery. We used airborne imaging spectroscopy data from the Airborne Prism Experiment (APEX) sensor to: (1) investigate which spectral regions and spectral indices perform best in discriminating burned from unburned areas; and (...

ژورنال: مرتع 2022

Background and objectives: Alongside with the progresss in satellite sensors, their role on obtaining information and study of the environmental events and phenomena have become increasingly important. One of these precious data which is the basis for many planning and decision making in rangelands, is the above ground net primary production assements. The traditional method of estimating ANPP ...

2017
John E. Hobbie Gaius R. Shaver Edward B. Rastetter Jessica E. Cherry Scott J. Goetz Kevin C. Guay William A. Gould George W. Kling

Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arct...

2009
F. R. FOSBERG

The great Pacific groups of atolls are such archipelagoes as the Tuamotus, Carolines, Marshalls, Gilberts, the Phoenix-Ellice group, and those scattered clusters and individual islands collectively termed the Pacific Equatorial or Line Islands. The observations forming the basis of this paper were made on visits to all these groups, except the Phoenix-Ellice and Gilberts, as well as to the Aust...

Journal: :Saudi journal of biological sciences 2012
Abdulrahman Alatar Mohamed A El-Sheikh Jacob Thomas

THIS ARTICLE HAS BEEN RETRACTED please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Author. Data processing errors have resulted in misleading conclusions. The scientific community in King Saud University has serious concerns regarding the results and the article will be res...

Journal: :مرتع و آبخیزداری 0
محسن نقیلو کارشناس دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد جعفری استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد طهمورث 3 کارشناس ارشد آبخیزداری، ایران اصغر کهندل استادیار جهاد دانشگاهی واحد تهران، ایران فریناز همدانیان 5 فارغ التحصیل کارشناس ارشد مرتعداری، ایران

the purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. the study area is located in west of tehran province and southeast of hashtgerd, next to najm-abad village. after field studies, the index ...

2011
Wenhao Ou Wei Su Chen Wu ZhongZheng Zhu YanMin Li Shi Shen

WenHao Ou, Wei Su ** , Chen Wu, ZhongZheng Zhu, YanMin Li, Shi Shen (Collage of Information and Electrical Engineering, China Agricultural University, Beijing, 100083) Abstract:Landsat TM5 images are used to calculate and retrieve normalized difference vegetation index (NDVI) and land surface temperature (LST). Combining with two index mentioned, vegetation temperature condition index (VTCI) ca...

2015
Yan Yan Xuyang Lu Harpinder Sandhu

Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in T...

2002
J. Verbesselt P. Coppin

Recent studies have demonstrated that surface wetness can be inferred when thermal infrared measurements are coupled with a spectral vegetation index (VI) that is linearly related to percentage vegetation cover. Even though it has later been shown that a proper interpretation of this relationship requires additional information of soil evaporation and the fractional vegetation cover, the ‘tempe...

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