نتایج جستجو برای: total ratio vegetation index trvi

تعداد نتایج: 1555903  

2003
Dominique Bachelet Ronald P. Neilson Thomas Hickler Raymond J. Drapek James M. Lenihan Martin T. Sykes Benjamin Smith Stephen Sitch Kirsten Thonicke

[1] Simulations of potential vegetation distribution, natural fire frequency, carbon pools, and fluxes are presented for two DGVMs (Dynamic Global Vegetation Models) from the second phase of the Vegetation/Ecosystem Modeling and Analysis Project. Results link vegetation dynamics to biogeochemical cycling for the conterminous United States. Two climate change scenarios were used: a moderately wa...

2014
Biao Jia Haibing He Fuyu Ma Ming Diao Guiying Jiang Zhong Zheng Jin Cui Hua Fan

The main objective of this study was to develop a nondestructive method for monitoring cotton growth and N status using a digital camera. Digital images were taken of the cotton canopies between emergence and full bloom. The green and red values were extracted from the digital images and then used to calculate canopy cover. The values of canopy cover were closely correlated with the normalized ...

Journal: :ماشین های کشاورزی 0
محمدعلی رستمی محمد حسین رئوفت عبدالعباس جعفری محمد لغوی مهدی کسرایی سید محمدجعفر ناظم السادات

local information about tillage intensity and ground residue coverage is useful for policies in agricultural extension, tillage implement design and upgrading management methods. the current methods for assessing crop residue coverage and tillage intensity such as residue weighing methods, line-transect and photo comparison methods are tedious and time-consuming. the present study was devoted t...

Forest ecosystems are among the largest terrestrial carbon reservoirs on our planet earth thus playing a vital role in global carbon cycle. Presently, remote sensing techniques provide proper estimates of forest biomass and quantify carbon stocks. The present study has explored Landsat-8 sensor product and evaluated its application in biomass mapping and estimation. The specific objectives were...

Journal: :آب و خاک 0
خلیل مقدم خلیل مقدم افیونی افیونی جلالیان جلالیان عباسپور عباسپور دهقانی دهقانی

abstract surface soil shear strength is an effective parameter in soil erosion and runoff modeling, and known as soil erodibility index. this study was conducted to investigate and predict soil shear strength in central zagros region using multiple linear regressions (mlr). the study site was selected in rangeland and degraded-rangeland landuse with an area of 23562 ha. based on the maps of geo...

2017
Wenqian Zhao Xiang Zhao Tao Zhou Donghai Wu Bijian Tang Hong Wei

Along with global climate change, the occurrence of extreme droughts in recent years has had a serious impact on the Amazon region. Current studies on the driving factors of the 2005 and 2010 Amazon droughts has focused on the influence of precipitation, whereas the impacts of temperature and radiation have received less attention. This study aims to explore the climate-driven factors of Amazon...

2007
Bunkei Matsushita Wei Yang Jin Chen Yuyichi Onda Guoyu Qiu

Vegetation indices play an important role in monitoring variations in vegetation.The Enhanced Vegetation Index (EVI) proposed by the MODIS Land Discipline Groupand the Normalized Difference Vegetation Index (NDVI) are both global-based vegetationindices aimed at providing consistent spatial and temporal information regarding globalvegetation. However, many environmental factors such as atmosphe...

2004
Ping Zhang Bruce Anderson Mathew Barlow Bin Tan Ranga B. Myneni

[1] MODIS-based leaf area index (LAI) and normalized difference vegetation index (NDVI) are used to examine detailed information regarding actual growing season and total annual production for various regions. Overall, MODIS LAI has larger variability and demonstrates more information regarding the evolution and structure of the seasonal vegetation characteristics. In contrast, the NDVI saturat...

More than one-third of the earth is characterized by arid and semi-arid climate and desertification phenomenon in these areas has been intensified in recent decades. This study aims to investigate the trend of desertification using vegetation indices and Iranian Model of Desertification Potential Assessment (IMDPA) in Abarkooh Plain, Yazd province, Iran. The satellite images (Landsat images in ...

Journal: :مرتع و آبخیزداری 0
افشین جهانشاهی دانشجوی دکتری آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی ساری علیرضا مقدم نیا دانشیار دانشکدة منابع طبیعی دانشگاه تهران حسن خسروی استادیار دانشکدة منابع طبیعی دانشگاه تهران

to assessment and preparation of desertification mapping, much research has been conducted ever within and outside the country that has led to numerous regional models. to provide a regional model and quantitative assessment of current state of desertification, shahrbabak plain with an area of 4112 square kilometers (km2) located in the northwest of kerman province were considered. in this stud...

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