Large Scale Remote Observations of Disturbance in the Amazon Basin
Global biogeochemical models need land cover change estimates annually at a 0.5 degree resolution. One potential source of this annual product is an interpolation between the decadally spaced maps derived from high resolution (30-m) TM imagery. Another option is to use annual coarse resolution (8-km) AVHRR imagery. We report initial results using aggregated 48-km AVHRR data (0.5 degrees), calibrated with Landsat TM data, to evaluate historical disturbance patterns (1981-1994) for an area in the Amazon region. Optical measurements from AVHRR almost certainly contain artifacts that mask subtle year-to-year changes in reflectance associated with the removal of some small fraction of forest from a 48-km grid cell. Despite this, we have developed a model based on NDVI and TM which appears to capture some details of the spatial and temporal patterns of disturbance. Though tropical rainforest monitoring is in many ways a remote sensing worst-case scenario because of the region's high cloud frequency and the dominance of other atmospheric constituents in the signal, this study suggests that AVHRR data contain information about disturbance patterns and rates.
Earth Sciences, Earth Systems Research Center
EOS, Transactions American Geophysical Union, Fall Meeting, Supplement
American Geophysical Union Publications
Hagen, S., Braswell, B., Salas, W., Xiao, X. and Frolking, S., Large Scale Remote Observations of Disturbance in the Amazon Basin, Eos Trans. AGU, 81(48), Fall Meet. Suppl., Abstract B71D-01, 2000.