Two-weekly AVHRR images were used to examine spatial patterns of the normalized difference vegetation index (NDVI) and their relationships with environmental variables for moist acidic tundra (MAT) and moist non-acidic tundra (MNT) along two latitudinal transects in northern Alaska. The NDVI database was derived from a 5-yr time series (1995-1999) of two-weekly AVHRR composites for Alaska. A di...

In the first section of this study, we explored the relationship between ring width index (RWI) and normalized difference vegetation index (NDVI) time series on varying timescales and spatial resolutions, hypothesizing positive associations between RWI and current and previousyear NDVI at 69 forest sites scattered in the Northern Hemisphere. We noted that the relationship between RWI and NDVI v...

On the basis of AVHRR GIMMS NDVI and MODIS NDVI, we constructed monthly NDVI sequences covering Northeast China from 1982 to 2009 using a per-pixel unary linear regression model. The expanded NDVI passed the consistency check and were well used for analysis. The monthly NDVI trends were highly correlated with climatic changes. Spatially averaged NDVI in summer exhibited a downward trend with

Due to technical limitations, it is impossible to have high resolution in both spatial and temporal dimensions for current NDVI datasets. Therefore, several methods are developed to produce high resolution (spatial and temporal) NDVI time-series datasets, which face some limitations including high computation loads and unreasonable assumptions. In this study, an unmixing-based method, NDVI Line...

Based on MODIS NDVI and NOAA NDVI datum, covering the primary grassland types of Inner Mongolian in growing seasons from 2000 to 2003, this paper analyzes annual variation rule of the relationship between MODIS NDVI and NOAA NDVI datum. We use the theory of statistics to discuss the spatial scaling methods between different resolutions images of remote sensing in large-scale spatial extent. At ...

The spatial heterogeneity of recent decadal dynamics in vegetation greenness and biomass in response to changes in summer warmth index (SWI) was investigated along spatial gradients on the Arctic Slope of Alaska. Image spatial analysis was used to examine the spatial pattern of greenness dynamics from 1991 to 2000 as indicated by variations of the maximum normalized difference vegetation index ...

Accurate monitoring of vegetation dynamics is required to understand the inter-annual variability and long term trends in terrestrial carbon exchange in tundra and boreal ecoregions. In western North America, two Normalized Vegetation Index (NDVI) products based on spectral reflectance data from the Moderate Resolution Imaging Spectroradiometer (MODIS) are available. The MOD/MYD13A2 NDVI produc...

Aim To examine the trends of 1982–2003 satellite-derived normalized difference vegetation index (NDVI) values at several spatial scales within tundra and boreal forest areas of Alaska. Location Arctic and subarctic Alaska. Methods Annual maximum NDVI data from the twice monthly Global Inventory Modelling and Mapping Studies (GIMMS) NDVI 1982–2003 data set with 64-km 2 pixels were extracted from...

Understanding the distribution of landscape variables presents several advantages to researchers focusing on ecological studies. The Normalized Difference Vegetation Index (NDVI) is a relatively common productivity variable used to assess, monitor, and compare landscapes. In this study, an NDVI layer was created using Satellite Pour l'Observation de la Terre 4 (SPOT 4) satellite imagery to comp...

This work modelled the spatial distribution of the rodent species that act as hosts in the transmission cycle of the parasitic tapeworm Echinococcus multilocularis. The rodent distribution was modelled in relation to landscape characteristics in four ways, using (1) a Landsat ETM+ derived hard classification, (2) single-image Landsat ETM+ derived NDVI, (3) single-image MODIS 16-day composite ND...