CALIPSO observations of stratospheric aerosols: a preliminary assessment

[摘要] We have examined the 532-nm aerosol backscatter coefficient measurements bythe Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO) for their use in the monitoring of stratospheric aerosol. CALIPSOmakes observations that span from 82° S to 82° N each day and, foreach profile, backscatter coefficient values reported up to ~40 km.The possibility of using CALIPSO for stratospheric aerosol monitoring isdemonstrated by the clear observation of the 20 May 2006 eruption ofMontserrat in the earliest CALIPSO data in early June as well as byobservations showing the 7 October 2006 eruption of Tavurvur (Rabaul).However, the very low aerosol loading within the stratosphere makes routineobservations of the stratospheric aerosol far more difficult than relativelydense volcanic plumes. Nonetheless, we found that averaging a complete daysworth of nighttime-only data into 5-deg latitude by 1-km vertical binsyields a stratospheric aerosol distribution that is fairly consistent withpast measurements by spaceborne instruments. Based on comparisons with 2004data from the Stratospheric Aerosol and Gas Experiment, the derived valuesare close to expectation except in the tropics where they are larger byabout a factor of 2. The cause of the difference in the tropics is notreadily apparent but is most likely related to difficulties in the lidarcalibration process currently found in the CALIOP data at tropical latitudes.

[学科分类] 大气科学