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Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua ConsistencyThe Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.
Document ID
20160000987
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sayer, A. M. (Universities Space Research Association Greenbelt, MD, United States)
Hsu, N. C. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Bettenhausen, C. (Science Systems and Applications, Inc. Lanham, MD, United States)
Jeong, M.-J. (Gangneung-Wonju National Univ. Gangneung, Korea, Republic of)
Meister, G. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
January 20, 2016
Publication Date
December 14, 2015
Publication Information
Publication: Journal of Geophysical Research: Atmospheres
Volume: 120
Issue: 23
Subject Category
Earth Resources and Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN25224
Funding Number(s)
CONTRACT_GRANT: NNG12HP08C
CONTRACT_GRANT: NNG11HP16A
Distribution Limits
Public
Copyright
Other
Keywords
Collection 6 Deep Blue
MODIS
aerosol products