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Improvement of Aerosol Optical Depth Retrieval from MODIS Spectral Reflectance over the Global Ocean Using New Aerosol Models Archived from AERONET Inversion Data and Tri-axial Ellipsoidal Dust DatabaseNew over-ocean aerosol models are developed by integrating the inversion data from the Aerosol Robotic Network (AERONET) sun/sky radiometers with a database for the optical properties of tri-axial ellipsoid particles. The new aerosol models allow more accurate retrieval of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) in the case of high AOD (AOD greater than 0.3). The aerosol models are categorized by using the fine-mode fraction (FMF) at 550 nm and the singlescattering albedo (SSA) at 440 nm from the AERONET inversion data to include a variety of aerosol types found around the globe. For each aerosol model, the changes in the aerosol optical properties (AOPs) as functions of AOD are considered to better represent aerosol characteristics. Comparisons of AODs between AERONET and MODIS for the period from 2003 to 2010 show that the use of the new aerosol models enhances the AOD accuracy with a Pearson coefficient of 0.93 and a regression slope of 0.99 compared to 0.92 and 0.85 calculated using the MODIS Collection 5 data. Moreover, the percentage of data within an expected error of +/-(0.03 + 0.05xAOD) is increased from 62 percent to 64 percent for overall data and from 39 percent to 51 percent for AOD greater than 0.3. Errors in the retrieved AOD are further characterized with respect to the Angstrom exponent (AE), scattering angle, SSA, and air mass factor (AMF). Due to more realistic AOPs assumptions, the new algorithm generally reduces systematic errors in the retrieved AODs compared with the current operational algorithm. In particular, the underestimation of fine-dominated AOD and the scattering angle dependence of dust-dominated AOD are significantly mitigated as results of the new algorithm's improved treatment of aerosol size distribution and dust particle nonsphericity.
Document ID
20140011354
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.5194/acp-12-7087-2012
Authors
Lee, J. (Maryland Univ. College Park, MD, United States)
Kim, J. (Yonsei Univ. Seoul, Korea, Republic of)
Yang, P. (Texas A&M Univ. College Station, TX, United States)
Hsu, N. C. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 3, 2014
Publication Date
August 6, 2012
Publication Information
Publication: Atmospheric Chemistry and Physics
Publisher: European Geophysical Union
Volume: 12
Issue: 15
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN8829
Funding Number(s)
CONTRACT_GRANT: NSF ATM-0803779
CONTRACT_GRANT: NNX12AD03A
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
aerosol optical depth
AERONET
MODIS

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