The CALIPSO Lidar Cloud and Aerosol Discrimination: Version 2 Algorithm and Initial Assessment of Performance

• DOI: 10.1175/2009jtecha1229.1
• Publication Date: 2009-02-07T08:28:10Z
• Authors: Zhaoyan Liu; Mark Vaughan; David Winker; Chieko Kittaka; Brian Getzewich; Ralph Kuehn; Ali Omar; Kathleen Powell; Charles Trepte; Chris Hostetler
• Keywords: Pathfinder; Cloud fraction; Cloud top

Abstract The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite was launched in April 2006 to provide global vertically resolved measurements of clouds aerosols. Correct discrimination between aerosols observed by the lidar aboard CALIPSO is critical for accurate retrievals cloud aerosol optical properties correct interpretation measurements. This paper reviews theoretical basis (CAD) algorithm, describes enhancements made version 2 algorithm that used current data release (release 2). also presents a preliminary assessment CAD performance based on one full day (12 August 2006) expert manual classification month (July CALIOP 5-km layer products. Overall, works well most cases. 1-day verification suggests success rate neighborhood 90% or better. Nevertheless, several specific types are still misclassified with some frequency. Among these, prevalent dense dust smoke close source regions. analysis July showed misclassification as occurs <1% total tropospheric features found. Smoke layers less frequently than layers. Optically thin polar regions can be While fraction such misclassifications small compared number found globally, caution should taken when studies performed Modifications will future releases, encountered expected reduced greatly.