HR: 0830h
AN: B21E-0762    [PDF]
TI: Inter-comparison of MODIS and AVHRR NDVI Time Series for Monitoring Terrestrial Vegetation
AU: * Reed, B
EM: reed@usgs.gov
AF: SAIC, USGS EROS Data Center, Sioux Falls, SD 57198 United States
AU: Dwyer, J
EM: dwyer@usgs.gov
AF: SAIC, USGS EROS Data Center, Sioux Falls, SD 57198 United States
AB: The moderate resolution imaging spectroradiometer (MODIS) is NASA's primary Earth observation sensor for global change studies. With the launch of the Terra satellite in 1999 and Aqua in 2002, improved data for land studies of radiation budget, ecosystems, and land cover characteristics, as well as ocean and atmospheric data, became available to scientists. One ecosystem variable that has been extensively used for remote sensing studies of global change is the normalized difference vegetation index (NDVI), a greenness measure that is linearly related to several biophysical measures such as fraction of photosynthetically active radiation (fPAR) and leaf area index (LAI). The value of the NDVI is that it has been calculated for many years from a heritage satellite sensor, the advanced very high resolution radiometer (AVHRR), thus establishing a useful time-series of global change related data. However, due to several differences between MODIS and AVHRR, including sensor radiometery, spectral resolution, and overpass time, direct comparisons and transitions are not readily made. This poster describes a dataset that has been created by the US Geological Survey to facilitate such comparisons and to document and characterize the similarities and differences between the sensors. Early results indicate similar temporal trajectories of the two time-series, but the NDVI from MODIS has generally slightly higher values than that from AVHRR. This indicates that temporal studies between the sensors may not require extensive corrections, but studies concerned with the magnitude of the NDVI will require considerable adjustment. In addition, several metrics derived from the NDVI temporal trajectories may be used to describe and associate the phenologic state of vegetation within the context of regional climatic influences.
DE: 0400 Biogeosciences
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting