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New Aerosol Models for the Retrieval of Aerosol Optical Thickness and Normalized Water-Leaving Radiances from the SeaWiFS and MODIS Sensors Over Coastal Regions and Open OceansWe describe the development of a new suite of aerosol models for the retrieval of atmospheric and oceanic optical properties from the SeaWiFs and MODIS sensors, including aerosol optical thickness (tau), angstrom coefficient (alpha), and water-leaving radiance (L(sub w)). The new aerosol models are derived from Aerosol Robotic Network (AERONET) observations and have bimodal lognormal distributions that are narrower than previous models used by the Ocean Biology Processing Group. We analyzed AERONET data over open ocean and coastal regions and found that the seasonal variability in the modal radii, particularly in the coastal region, was related to the relative humidity, These findings were incorporated into the models by making the modal radii, as well as the refractive indices, explicitly dependent on relative humidity, From those findings, we constructed a new suite of aerosol models. We considered eight relative humidity values (30%, 50%, 70%, 75%, 80%, 85%, 90%. and 95%) and, for each relative humidity value, we constructed ten distributions by varying the fine-mode fraction from zero to 1. In all. 80 distributions (8Rh x 10 fine-mode fractions) were created to process the satellite data. We. also assumed that the coarse-mode particles were nonabsorbing (sea salt) and that all observed absorptions were entirely due to fine-mode particles. The composition of fine mode was varied to ensure that the new models exhibited the same spectral dependence of single scattering albedo as observed in the AERONET data,
Document ID
20110007945
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Ahmad, Ziauddin (Science and Data Systems, Inc. Silver Spring, MD, United States)
Franz, Bryan A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
McClain, Charles R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kwiatkowska, Ewa J. (Science and Data Systems, Inc. Silver Spring, MD, United States)
Werdell, Jeremy (Science Systems and Applications, Inc. Lanham, MD, United States)
Shettle, Eric P. (Naval Research Lab. Washington, DC, United States)
Holben, Brent N. (Science and Data Systems, Inc. Silver Spring, MD, United States)
Date Acquired
August 25, 2013
Publication Date
October 5, 2010
Publication Information
Publication: Applied Optics
Volume: 49
Issue: 29
Subject Category
Optics
Distribution Limits
Public
Copyright
Other