نتایج جستجو برای: ndvi

تعداد نتایج: 5798  

Journal: :Ecology 2007
Nathalie Pettorelli Fanie Pelletier Achaz Von Hardenberg Marco Festa-Bianchet Steeve D Côté

Seasonal patterns of climate and vegetation growth are expected to be altered by global warming. In alpine environments, the reproduction of birds and mammals is tightly linked to seasonality; therefore such alterations may have strong repercussions on recruitment. We used the normalized difference vegetation index (NDVI), a satellite-based measurement that correlates strongly with aboveground ...

2003

Crop coefficients are a widely used and universally accepted method for estimating the crop evapotranspiration (ETc) component in irrigation scheduling programs. However, uncertainties of generalized basal crop coefficient (Kcb) curves can contribute to ETc estimates that are substantially different from actual ETc. Limited research with corn has shown improvements to irrigation scheduling due ...

2016
Long Wan Jing Tong Jinxing Zhou Hongyan Guo Ming Cui Yuguo Liu Like Ning Fukai Tang

Over the past several decades, rocky desertification has led to severe ecological problems in karst areas in South China. After a rocky desertification treatment project was completed, the vegetation coverage changed greatly and, consequently, increased the ecology water consumption (approximately equal to the actual evapotranspiration) of the regional vegetation. Thus, it intensified the regio...

2015
C. S. Murthy M. V.R. Sesha Sai M. Naresh Kumar P. S. Roy

Time series data on cropping pattern at disaggregated level were analysed and its implications on geospatial drought assessment were demonstrated. An index of Cropping Pattern Dissimilarity (CP-DI) between a pair of years, developed in this study, proved that the cropping pattern of a year has a higher degree of similarity with that of recent past years only and tends to be dissimilar with long...

Journal: :Remote Sensing 2010
Ainong Li Wei Deng Shunlin Liang Chengquan Huang

The pattern of vegetation change in response to global change still remains a controversial issue. A Normalized Difference Vegetation Index (NDVI) dataset compiled by the Global Inventory Modeling and Mapping Studies (GIMMS) was used for analysis. For the period 1982–2006, GIMMS-NDVI analysis indicated that monthly NDVI changes show homogenous trends in middle and high latitude areas in the nor...

2004
Lee F. Johnson Thibaut Scholasch

Normalized difference vegetation index (NDVI) data, acquired at two-meter resolution by an airborne ADAR System 5500, were compared with fraction of photosynthetically active radiation (FPAR) absorbed by commercial vineyards in Napa Valley, California. An empirical line correction was used to transform image digital counts to surface reflectance. “Apparent” NDVI (generated from digital counts) ...

1996
Tim Hess William Stephens Graham Thomas

The Normalised Difference Vegetation Index (NDVI) can be calculated from satellite imagery and is generally recognised as a reliable index of ground vegetation cover. A simple, parsimonious model is presented to relate observed levels of the NDVI to decadal (10-day) rainfall over the preceding seven months. The model was calibrated at four stations in the North East Arid Zone of Nigeria over te...

Journal: :Remote Sensing 2017
Peter J. Olsoy Jessica J. Mitchell Nancy F. Glenn Alejandro N. Flores

Water-limited ecosystems encompass approximately 40% of terrestrial land mass and play a critical role in modulating Earth’s climate and provisioning ecosystem services to humanity. Spaceborne remote sensing is a critical tool for characterizing ecohydrologic patterns and advancing the understanding of the interactions between atmospheric forcings and ecohydrologic responses. Fine to medium sca...

2013
Elena Tarnavsky Sebastien Garrigues Molly E. Brown

Global NDVI data are routinely derived from the AVHRR, SPOT-VGT, and MODIS/Terra earth observation records for a range of applications from terrestrial vegetation monitoring to climate change modeling. This has led to a substantial interest in the harmonization of multisensor records. Most evaluations of the internal consistency and continuity of global multisensor NDVI products have focused on...

Journal: :Remote Sensing 2012
Prajna Regmi Guido Grosse Miriam C. Jones Benjamin M. Jones Katey Walter Anthony

Drained thermokarst lake basins accumulate significant amounts of soil organic carbon in the form of peat, which is of interest to understanding carbon cycling and climate change feedbacks associated with thermokarst in the Arctic. Remote sensing is a tool useful for understanding temporal and spatial dynamics of drained basins. In this study, we tested the application of high-resolution X-band...

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