نتایج جستجو برای: normalized difference vegetation index ndvi

تعداد نتایج: 859215  

2006
J. Kim Q. Guo D. D. Baldocchi M. Y. Leclerc L. Xu H. P. Schmid

In this paper, we describe the process of assessing tower footprint climatology, spatial variability of site vegetation density based on satellite image analysis, and sensor location bias in scaling up to 1 km 1 km patch. Three flat sites with different vegetation cover and surface heterogeneity were selected from AmeriFlux tower sites: the oak/grass site and the annual grassland site in a sava...

1997
Zhengming Wan

The global land-surface temperature (LST) and normalized difference vegetation index (NDVI) products retrieved fromModerate Resolution Imaging Spectroradiometer (MODIS) data in 2001 were used in this study. The yearly peak valuesof NDVI data at 5km grids were used to define six NDVI peak zones from -0.2 to 1 in steps of 0.2, and the monthlyNDVI values at each grid were sorted in dec...

Akhoondzadeh , Mahdi , Mokhtari Dehkordi, Ramin ,

The drought can be described as a natural disaster in each region. In this study, one of the important factors in drought, vegetation, has been considered. For this purpose, monthly vegetation cover images and snow cover data of MODIS and TRMM satellite precipitation product from 2009 to 2018 were used for the study area of Iran. After initial preprocessing, we have used artificial neural netwo...

2017
Xiaobo Luo Weisheng Li

Several indices, including the normalized difference vegetation index (NDVI), normalized difference build-up index (NDBI), and normalized difference water index (NDWI), were retrieved from the Landsat 5 Thematic Mapper (TM) images, and the land surface temperature (LST) was reversed by the thermal radiation transfer model. Next, with the help of the thermal field variance index from LST, charac...

2017
Safa Bousbih Mehrez Zribi Zohra Lili-Chabaane Nicolas Baghdadi Mohammad El-Hajj Qi Gao Bernard Mougenot

The main objective of this study is to analyze the potential use of Sentinel-1 (S1) radar data for the estimation of soil characteristics (roughness and water content) and cereal vegetation parameters (leaf area index (LAI), and vegetation height (H)) in agricultural areas. Simultaneously to several radar acquisitions made between 2015 and 2017, using S1 sensors over the Kairouan Plain (Tunisia...

2008
Juan Gu Xin Li Chunlin Huang

Consistent Normalized Difference of Vegetation Index (NDVI) time series, as paramount and powerful tool, can be used to monitor ecological resources that are being altered by climate and human impacts, since its temporal evolution is strongly linked to changes in the state of land surface. However, the noise caused mainly by cloud contamination, heavy aerosol, atmospheric variability and signal...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2010
Alemu Gonsamo

This study is aimed at demonstrating the feasibility of the large scale LAI inversion algorithms using red and near infrared reflectance obtained from high resolution satellite imagery. Radiances in digital counts were obtained in 10m resolution acquired on cloud free day of August 23, 2007, by the SPOT 5 high resolution geometric (HRG) instrument onmostly temperatehardwood forest located in th...

Journal: :اکو هیدرولوژی 0
مهسا خدایی کارشناس ارشد مهندسی سنجش از دور، دانشکدۀ عمران، دانشگاه فردوسی مشهد روزبه شاد استادیار، دانشکدۀ عمران، دانشگاه فردوسی مشهد یاسر مقصودی مهرانی استادیار، دانشکدۀ ژئوماتیک، دانشگاه خواجه نصیر الدین طوسی مرجان قائمی استادیار، دانشکدۀ عمران، دانشگاه فردوسی مشهد

in this article, new index, the optimized synthetized drought index (osdi), is suggested for real-time monitoring of this phenomenon in areas with heterogeneous land covers. the precipitation, one of the important factors in drought, measured by ground stations and improved bytrmm satellite data. each of the three normalized moisture indices, including normalized difference vegetation index (nd...

Journal: :ISPRS Int. J. Geo-Information 2017
Ling Wang Bingwei Tian Katsuaki Koike Buting Hong Ping Ren

The quantification of spatial heterogeneity can be used to examine the structure of ecological systems. The 2008 Wenchuan earthquake caused severe vegetation damage. In addition to simply detecting change, the magnitude of changes must also be examined. Remote sensing and geographic information system techniques were used to produce landscape maps before and after the earthquake and analyze the...

2002
LIXIN LU W. JAMES SHUTTLEWORTH

In this study, a climate version of the Regional Atmospheric Modeling System (ClimRAMS) was used to investigate the sensitivity of regional climate simulations to changes in vegetation distribution in the Great Plains and Rocky Mountain regions of the United States. The evolution of vegetation phenology was assimilated into the ClimRAMS in the form of estimates of the leaf area index (LAI) deri...

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