Selection Algorithm for the CALIPSO Lidar Aerosol Extinction-to-Backscatter Ratio

Ali H. Omar, David M. Winker, Jae Gwang Won, Mark A. Vaughan, Chris A. Hostetler, John A. Reagan

Research output: Contribution to conferencePaperpeer-review

10 Scopus citations


The extinction-to-backscatter ratio (Sa) is an important parameter used in the determination of the aerosol extinction and subsequently the optical depth from lidar backscatter measurements. We outline the algorithm used to determine Sa for the Cloud and Aerosol Lidar and Infrared imager Pathfinder Spaceborne Observations (CALIPSO) lidar. Sa of the CALIPSO lidar will either be selected from a look-up table or calculated using the lidar measurements depending on the characteristics of aerosol layer. When lofted layers are encountered, Sa is computed directly from the integrated backscatter and transmittance. In all other cases, the CALIPSO observables: the depolarization ratio δ, the layer integrated attenuated backscatter γ', and the mean layer total attenuated color ratio χ, together with the surface type, are used to aid in aerosol typing. Once the type is identified, a look-up-table developed primarily from worldwide observations, is used to determine the Sa value. For aerosols in non-polar regions, CALIPSO aerosol models include desert dust, biomass burning, background, polluted continental, polluted dust, and marine aerosols. The polar aerosols are classified into three groups: arctic, polluted arctic, and antarctic aerosols.

Original languageEnglish (US)
Number of pages5
StatePublished - 2003
Externally publishedYes
Event2003 IGARSS: Learning From Earth's Shapes and Colours - Toulouse, France
Duration: Jul 21 2003Jul 25 2003


Other2003 IGARSS: Learning From Earth's Shapes and Colours

ASJC Scopus subject areas

  • Computer Science Applications
  • Earth and Planetary Sciences(all)


Dive into the research topics of 'Selection Algorithm for the CALIPSO Lidar Aerosol Extinction-to-Backscatter Ratio'. Together they form a unique fingerprint.

Cite this