SATELLITE-SENSED DISTRIBUTION AND SPATIAL PATTERNS OF VEGETATION PARAMETERS OVER A TALLGRASS PRAIRIE

Remotely sensed images of vegetation density expressed as the Normaliz ed Difference Vegetation index (NDVI) recorded during the First ISLSCP (International Satellite Land Surface Climatology Project) Field Expe riment were mapped on the same coordinate system covering the 20 km x 20 km experimental site. The temporal behavior of frequency distributi ons and semivariograms of the NDVI exhibited similarity; these distrib utions were quite Symmetric, except near the extremes. Although values at individual locations showed considerable scatter, when averaged ov er the experimental area, the NDVI values were well correlated with gr ound-based measurements of the leaf area index. The persistence tenden cies of the spatial patterns of NDVI were evaluated through correlatio n analysis of the images on successive days. The spatial patterns were preserved well during wet periods; they gradually changed by deep dry ing of the soil but were restored after heavy rainfall.