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MODIS Retrieval of Dust AerosolThe MODerate resolution Imaging Spectroradiometer (MODIS) currently aboard both the Terra and Aqua satellites produces a suite of products designed to characterize global aerosol distribution, optical thickness and particle size. Never before has a space-borne instrument been able to provide such detailed information, operationally, on a nearly global basis every day. The three years of Terra-MODIS data have been validated by comparing with co-located AERONET observations of aerosol optical thickness and derivations of aerosol size parameters. Some 8000 comparison points located at 133 AERONET sites around the globe show that the MODIS aerosol optical thickness retrievals are accurate to within the pre-launch expectations. However, the validation in regions dominated by desert dust is less accurate than in regions dominated by fine mode aerosol or background marine sea salt. The discrepancy is most apparent in retrievals of aerosol size parameters over ocean. In dust situations, the MODIS algorithm tends to under predict particle size because the reflectances at top of atmosphere measured by MODIS exhibit the stronger spectral signature expected by smaller particles. This pattern is consistent with the angular and spectral signature of non-spherical particles. All possible aerosol models in the MODIS Look-Up Tables were constructed from Mie theory, assuming a spherical shape. Using a combination of MODIS and AERONET observations, in regimes dominated by desert dust, we construct phase functions, empirically, with no assumption of particle shape. These new phase functions are introduced into the MODIS algorithm, in lieu of the original options for large dust-like particles. The results will be analyzed and examined.
Document ID
20040035547
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Remer, Lorraine A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kaufman, Yoram J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Tanre, Didier
(Lille Univ. France)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: 2nd International Workshop on Mineral Dust
Location: Paris
Country: France
Start Date: September 10, 2003
End Date: September 12, 2003
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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