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Multiangle Imaging Spectroradiometer (MISR) Global Aerosol Optical Depth Validation Based on 2 Years of Coincident Aerosol Robotic Network (AERONET) ObservationsPerformance of the Multiangle Imaging Spectroradiometer (MISR) early postlaunch aerosol optical thickness (AOT) retrieval algorithm is assessed quantitatively over land and ocean by comparison with a 2-year measurement record of globally distributed AERONET Sun photometers. There are sufficient coincident observations to stratify the data set by season and expected aerosol type. In addition to reporting uncertainty envelopes, we identify trends and outliers, and investigate their likely causes, with the aim of refining algorithm performance. Overall, about 2/3 of the MISR-retrieved AOT values fall within [0.05 or 20% x AOT] of Aerosol Robotic Network (AERONET). More than a third are within [0.03 or 10% x AOT]. Correlation coefficients are highest for maritime stations (approx.0.9), and lowest for dusty sites (more than approx.0.7). Retrieved spectral slopes closely match Sun photometer values for Biomass burning and continental aerosol types. Detailed comparisons suggest that adding to the algorithm climatology more absorbing spherical particles, more realistic dust analogs, and a richer selection of multimodal aerosol mixtures would reduce the remaining discrepancies for MISR retrievals over land; in addition, refining instrument low-light-level calibration could reduce or eliminate a small but systematic offset in maritime AOT values. On the basis of cases for which current particle models are representative, a second-generation MISR aerosol retrieval algorithm incorporating these improvements could provide AOT accuracy unprecedented for a spaceborne technique.
Document ID
20070034029
Acquisition Source
Jet Propulsion Laboratory
Document Type
Reprint (Version printed in journal)
Authors
Kahn, Ralph A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Gaitley, Barbara J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Martonchik, John V.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Diner, David J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Crean, Kathleen A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Holben, Brent
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
March 9, 2005
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 110
ISSN: 0148-0227
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Other
Keywords
global meaurement
aerosol

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