HR: 1340h
AN: B43B-0267    [Abstracts]
TI: A Comparison of Vegetation Phenology Estimated From AVHRR and MODIS Data
AU: * Tan, B
EM: tanbin@crsa.bu.edu
AF: Department of Geography, Boston University 675 Commonwealth Ave., Boston, MA 02215 United States
AU: Friedl, M
EM: friedl@bu.edu
AF: Department of Geography, Boston University 675 Commonwealth Ave., Boston, MA 02215 United States
AB: The Advanced Very High Resolution Radiometer (AVHRR) has been used for over a decade to study vegetation phenology from space. Using normalized difference vegetation index (NDVI) data, a variety of studies have demonstrated the utility of the AVHRR for studying a wide range of questions related to seasonal and interannual dynamics in vegetation. Indeed, the longer time series (over twenty years) provided by AVHRR data provides a unique opportunity for studying both long term (decadal) and shorter term (internannual) variability in vegetation dynamics. At the same time, a variety of issues constrain the effectiveness of AVHRR data for this purpose including relatively poor spatial co-registration of images, crude atmospheric correction, calibration problems, and less-than-ideal cloud screening. Since April of 2000, the Moderate Resolution Imaging Spectroradiometer (MODIS) has been providing imagery of the Earth that reduces the severity of many of these constraints. In this paper, we report results from a study comparing vegetation phenological metrics estimated from MODIS and AVHRR. Using selected tiles covering a range of different climate and ecosystem types, we applied the MODIS global vegetation phenology algorithm to both MODIS and AVHRR data sets. The algorithm was applied to 16-day enhanced vegetation index (EVI) data computed from MODIS, and to 15-day NDVI data computed from AVHRR for dates spanning the growing season in the Northern Hemisphere for 2000-2004. In addition, we also applied the MODIS phenology algorithm to the entire time series of AVHRR data for the selected tiles. Results show (1) distinct differences in phenology inferred from MODIS versus AVHRR, and (2) evidence of correspondence between climate forcing and vegetation phenology for the twenty two year period considered.
DE: 0429 Climate dynamics (1620)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0480 Remote sensing
DE: 1630 Impacts of global change (1225)
DE: 1637 Regional climate change
SC: Biogeosciences [B]
MN: Fall Meeting 2005