HR: 0800h
AN: B21A-0037    [Abstracts]
TI: Investigation of uncertainty in surface reflectance measures derived from AVHRR caused by orbital drift and variations in viewing geometry.
AU: * Nagol, J R
EM: jnagol@umd.edu
AF: University Of Maryland College Park, Department of Geography, 2181 LeFrak Hall, University of Maryland, College Park, MD 20742,
AU: Vermote, E
EM: eric@kratmos.gsfc.nasa.gov
AF: University Of Maryland College Park, Department of Geography, 2181 LeFrak Hall, University of Maryland, College Park, MD 20742,
AU: Vermote, E
EM: eric@kratmos.gsfc.nasa.gov
AF: NASA GSFC Code 614.5, NASA Goddard Space Flight Center, Greenbelt, 20771,
AU: Prince, S
EM: sprince@geog.umd.edu
AF: University Of Maryland College Park, Department of Geography, 2181 LeFrak Hall, University of Maryland, College Park, MD 20742,
AU: Brown, M
EM: molly.brown@gsfc.nasa.gov
AF: SSAI/NASA GSFC Code 614.4, NASA Goddard Space Flight Center, Greenbelt, 20771,
AB: Data derived from the AVHRR (Advanced Very High Resolution Radiometer) series of instruments has been extensively used for monitoring global and regional vegetation dynamics for last 25+ years. Past studies have shown that the influence of systematic change in satellite overpass time during the course of satellite's life due to orbital drift remains, even after sensor calibration, owing to change in sun-sensor geometry. In order to assess the impacts of orbital drift on time-series analysis of derived metrics like vegetation indices and phenology. We investigated simulated AVHRR time series data created with actual AVHRR viewing and illumination geometry. To examine orbital drift alone interannual variations in phenology and atmospheric composition was not used in the simulations. A three dimensional canopy radiative transfer model (FLIGHT) was coupled with an atmospheric radiative transfer model (6s) to create simulated time series data for three AERONET sites to represent boreal forest, tropical forest, and semi-arid landcover. This was further used to compare various methods used to deal with impacts of orbital drift like EMD (Empirical Mode Decomposition) and semi empirical BRDF correction.
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: 2007 Fall Meeting