HR: 09:12h
AN: A21E-06    [Abstracts]
TI: Global Top-of-Atmosphere Direct Radiative Effect of Aerosols over Ocean from Merged CERES and MODIS Observations for 2000-2003
AU: * Loeb, N G
EM: n.g.loeb@larc.nasa.gov
AF: Hampton University, 23 Tyler Street, Hampton, VA 23668 United States
AU: Manalo-Smith, N
AF: Analytical Services and Materials, One Enterprise Pkwy, Hampton, VA 23666 United States
AU: Ignatov, A
AF: NOAA, 5200 Auth Rd, WWB, Rm 603, Camp Springs, MD 20746-4304 United States
AU: Remer, L A
AF: NASA/Goddard Space Flight Center, Code 913, Greenbelt, MD 20771 United States
AB: The direct effect of aerosols is defined as the difference between radiative fluxes in the absence and presence of aerosols. In this study, the direct radiative effect of aerosols is estimated for 46 months (March, 2000 to December, 2003) of merged CERES and MODIS Terra global measurements over ocean. Unlike previous studies, this analysis includes the contribution from clear regions in both cloud-free and partly cloudy CERES fields-of-view (FOVs). In partly cloudy conditions, the direct effect is derived by applying narrow-to-broadband radiance regressions to MODIS pixels identified as clear according to the Ignatov-Stowe aerosol retrieval algorithm. The narrow-to-broadband regression is a multi-channel regression that uses clear MODIS and CERES radiances. Radiative fluxes are determined from the radiances using angular distribution models developed from CERES. The global and regional 46-month time series of the aerosol direct effect will be presented to highlight its seasonal and year-to-year variation over roughly four years. To investigate the influence of cloud screening, the direct effect derived using clear regions identified with the Ignatov-Stowe approach will be compared with that using clear scenes from the MOD04 aerosol product for selected months.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0933 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting