SATELLITE-DERIVED VEGETATION INDEX AND COVER TYPE MAPS FOR ESTIMATINGCARBON-DIOXIDE FLUX FOR ARCTIC TUNDRA REGIONS

The spatial variability and co-variability of two different types of r emote sensing derivatives that portray vegetation and geomorphic patte rns are analyzed in the context of estimating regional-scale CO2 flux from land surfaces in the arctic tundra, For a study area encompassing the Kuparuk River watershed of the North Slope of Alaska, we compare satellite-derived maps of the normalized difference vegetation index ( NDVI) generated at two different spatial resolutions to a map of veget ation types derived by image classification of data from the Landsat m ultispectral scanner (MSS). Mean values of NDVI for each cover type st ratum are unique (with the exception of moist acidic tundra and shrubl and types), Based on analysis of semi-variograms generated for SPOT-ND VI data, most of the vegetation cover and landform features of this ar ctic tundra landscape have spatial dimensions of less than 1 km. Thaw lakes on the coastal plain and glacial depositional landforms, such as moraines in the foothills, seem to be the largest features, with vege tation units having dimensions no larger than 700 m. Frequency distrib utions of NDVI and vegetation types extracted for sampling transects f lown by an aircraft sensing CO2 flux, relative to distributions for th e entire Kuparuk River watershed, suggest a slight sampling bias towar ds greater cover of mesic wet sedge tundra and thaw lakes and associat ed lower NDVI values. The regional pattern of NDVI for the North Slope of Alaska corresponds primarily to differences between the two major physiographic provinces of this region. (C) 1998 Elsevier Science B.V.