Satellite-Sensed Distribution and Spatial Patterns of Vegetation Parameters over a Tallgrass Prairie

Abstract

Remotely sensed images of vegetation density expressed as the Normalized Difference Vegetation index (NDVI) recorded during the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment were mapped on the same coordinate system covering the 20 km ? 20 km experimental site. The temporal behavior of frequency distributions and semivariograms of the NDVI exhibited similarity; these distributions were quite symmetric, except near the extremes. Although values at individual locations showed considerable scatter, when averaged over the experimental area, the NDVI values were well correlated with ground-based measurements of the leaf area index. The persistence tendencies of the spatial patterns of NDVI were evaluated through correlation analysis of the images on successive days. The spatial patterns were preserved well during wet periods; they gradually changed by deep drying of the soil but were restored after heavy rainfall.