Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 20 2007 10.5194/acp-7-5283-2007 http://www.atmos-chem-phys.net/7/5283/2007/ http://www.atmos-chem-phys.net/7/5283/2007/acp-7-5283-2007.html http://www.atmos-chem-phys.net/7/5283/2007/acp-7-5283-2007.pdf 5283 5290 2007-10-15 CALIPSO observations of stratospheric aerosols: a preliminary assessment L. W. Thomason l.w.thomason@nasa.gov M. C. Pitts D. M. Winker NASA Langley Research Center, Hampton, VA, USA We have examined the 532-nm aerosol backscatter coefficient measurements by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) for their use in the monitoring of stratospheric aerosol. CALIPSO makes observations that span from 82° S to 82° N each day and, for each profile, backscatter coefficient values reported up to ~40 km. The possibility of using CALIPSO for stratospheric aerosol monitoring is demonstrated by the clear observation of the 20 May 2006 eruption of Montserrat in the earliest CALIPSO data in early June as well as by observations showing the 7 October 2006 eruption of Tavurvur (Rabaul). However, the very low aerosol loading within the stratosphere makes routine observations of the stratospheric aerosol far more difficult than relatively dense volcanic plumes. Nonetheless, we found that averaging a complete days worth of nighttime-only data into 5-deg latitude by 1-km vertical bins yields a stratospheric aerosol distribution that is fairly consistent with past measurements by spaceborne instruments. Based on comparisons with 2004 data from the Stratospheric Aerosol and Gas Experiment, the derived values are close to expectation except in the tropics where they are larger by about a factor of 2. 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