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Validating MODIS Above-Cloud Aerosol Optical Depth Retrieved from Color Ratio Algorithm Using Direct Measurements Made by NASA's Airborne AATS and 4STAR SensorsWe present the validation analysis of above-cloud aerosol optical depth (ACAOD) retrieved from the color ratio method applied to MODIS cloudy-sky reflectance measurements using the limited direct measurements made by NASAs airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database collection revealed a total of five significant events in which an airborne sun photometer, coincident with the MODIS overpass, observed partially absorbing aerosols emitted from agricultural biomass burning, dust, and wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne match ups revealed a good agreement (root-mean-square difference less than 0.1), with most match ups falling within the estimated uncertainties associated with the MODIS retrievals (about -10 to +50 ). The co-retrieved cloud optical depth was comparable to that of the MODIS operational cloud product for ACE-ASIA and SEAC4RS, however, higher by 30-50% for the SAFARI-2000 case study. The reason for this discrepancy could be attributed to the distinct aerosol optical properties encountered during respective campaigns. A brief discussion on the sources of uncertainty in the satellite-based ACAOD retrieval and co-location procedure is presented. Field experiments dedicated to making direct measurements of aerosols above cloud are needed for the extensive validation of satellite based retrievals.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Jethva, Hiren (Universities Space Research Association Columbia, MD, United States)
Torres, Omar (NASA Langley Research Center Hampton, VA United States)
Remer, Lorraine (Maryland Univ. Baltimore County Baltimore, MD, United States)
Redemann, Jens (NASA Ames Research Center Moffett Field, CA United States)
Livingston, John (SRI International Corp. Menlo Park, CA, United States)
Dunagan, Stephen (NASA Ames Research Center Moffett Field, CA United States)
Shinozuka, Yohei (Bay Area Environmental Research Inst. Moffett Field, CA, United States)
Kacenelenbogen, Meloe (Bay Area Environmental Research Inst. Moffett Field, CA, United States)
Segal Rozenhaimer, Michal (Bay Area Environmental Research Inst. Moffett Field, CA, United States)
Spurr, Rob (RT Solutions, Inc. Cambridge, MA, United States)
Date Acquired
April 7, 2017
Publication Date
October 14, 2016
Publication Information
Publication: Atmospheric Measurement Techniques
Volume: 9
Issue: 10
ISSN: 1867-1381
Subject Category
Earth Resources and Remote Sensing
Report/Patent Number
Funding Number(s)
Distribution Limits
airborne sun photometer