نتایج جستجو برای: normalized difference vegetation index ndvi

تعداد نتایج: 859215  

Journal: :Remote Sensing 2014
William Scheftic Xubin Zeng Patrick Broxton Michael Brunke

Satellites have provided large-scale monitoring of vegetation for over three decades, and several satellite-based Normalized Difference Vegetation Index (NDVI) datasets have been produced. Here we intercompare four long-term NDVI datasets based largely on the AVHRR sensor (NDVIg, NDVI3g, STAR, VIP) and three datasets based on newer sensors (SPOT, Terra, Aqua) and evaluate the effectiveness of h...

2008
Yingxin Gu Eric Hunt Brian Wardlow Jeffrey B. Basara Jesslyn F. Brown James P. Verdin

[1] The evaluation of the relationship between satellitederived vegetation indices (normalized difference vegetation index and normalized difference water index) and soil moisture improves our understanding of how these indices respond to soil moisture fluctuations. Soil moisture deficits are ultimately tied to drought stress on plants. The diverse terrain and climate of Oklahoma, the extensive...

2017
Xiaoyi Guo Hongyan Zhang Zhengfang Wu Jianjun Zhao Zhengxiang Zhang

Time series of Normalized Difference Vegetation Index (NDVI) derived from multiple satellite sensors are crucial data to study vegetation dynamics. The Land Long Term Data Record Version 4 (LTDR V4) NDVI dataset was recently released at a 0.05 × 0.05° spatial resolution and daily temporal resolution. In this study, annual NDVI time series that are composited by the LTDR V4 and Moderate Resoluti...

Journal: :Remote Sensing 2016
Dan J. Krofcheck Jan U. H. Eitel Christopher D. Lippitt Lee A. Vierling Urs Schulthess Marcy E. Litvak

Remote sensing is a key technology that enables us to scale up our empirical, in situ measurements of carbon uptake made at the site level. In low leaf area index ecosystems typical of semi-arid regions however, many assumptions of these remote sensing approaches fall short, given the complexities of the heterogeneous landscape and frequent disturbance. Here, we investigated the utility of remo...

Journal: :Remote Sensing 2013
J. Ronald Eastman Florencia Sangermano Elia Axinia Machado-Machado John Rogan Assaf Anyamba

A 30-year series of global monthly Normalized Difference Vegetation Index (NDVI) imagery derived from the Global Inventory Modeling and Mapping Studies (GIMMS) NDVI3g archive was analyzed for the presence of trends in changing seasonality. Using the Seasonal Trend Analysis (STA) procedure, over half (56.30%) of land surfaces were found to exhibit significant trends. Almost half (46.10%) of the ...

2009
Temuulen Tsagaan Sankey Keith T. Weber

Extensive livestock production has been Mongolia’s major industry for centuries and traditional nomadic herding lifestyle and Mongolia’s expansive rangelands sustain this industry. After the democratic election and economic liberalization in 1992, formerly state-owned collectives were disbanded and Mongolia’s livestock population was privatized. There was no longer a state institution to formal...

Journal: :International Journal of Geographical Information Science 2010
Thomas K. Alexandridis Thomas Katagis Ioannis Z. Gitas Nikolaos G. Silleos K. M. Eskridge G. Gritzas

Monitoring vegetation condition is an important issue in the Mediterranean region, in terms of both securing food and preventing fires. Vegetation indices (VIs), mathematical transformations of reflectance bands, have played an important role in vegetation monitoring, as they depict the abundance and health of vegetation. Instead of storing raster VI maps, aggregated statistics can be derived a...

2010
Angélica Giarolla Yosio E. Shimabukuro José dos Campos

This study aimed to evaluate the response of the Normalized Difference Vegetation Index NDVI derived from Terra MODIS sensor to soybean phenology, in a grain producer region of Parana State, Brazil. Landsat TM and ETM+ images were selected to analyze the spatial distribution of soybean fields for this region from 2000/01 to 2006/07 crop seasons. Then pure pixel samples (250 x 250m) that contain...

2013
GAN Wenxia SHEN Huanfeng ZHANG Liangpei GONG Wei

Medium Resolution NDVI( Normalized Difference Vegetation Index) from different sensor systems such as Landsat, SPOT, ASTER, CBERS and HJ-1A/1B satellites provide detailed spatial information for studies of ecosystems, vegetation biophysics, and land cover. Limitation of sensor designs, cloud contamination, and sensor failure highlighted the need to normalize and integrate NDVI from multiple sen...

2017
Xiaxiang Li Xuezhen Zhang Lijuan Zhang

The effect of vegetation on temperature is an emerging topic in the climate science community. Existing studies have mostly examined the effects of vegetation on daytime temperature (Tmax), whereas this study investigates the effects on nighttime temperature (Tmin). Ground measurements from 53 sites across northeastern China (NEC) from 1982 to 2006 show that early summer (June) Tmax and Tmin in...

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