CALIPSO-ST Description

Measurements

The CALIOP instrument onboard the NASA/CNES CALIPSO satellite has acquired profiles of atmospheric lidar backscatter since June 2006. CALIOP consists of a polarized laser transmitter operating at 532 nm and 1064 nm and a receiver which samples the backscattered laser pulses at a 10 MHz rate. Cloud and aerosol layers are identified, during both day and night, by comparing the measured signal with the signal predicted for a molecular atmosphere and cloud altitude is derived from time-of-flight measurements. Multiple cloud layers can be profiled, to an optical depth of about three.

Local Observation Time and Length of Data Record

1:30 AM and 1:30 PM ; 2007-2008

Spatial Resolution

0.06 km (vertical) x 0.34 km (horizontal)

Cloud Detection

Lidar VIS backscatter
Horizontal averaging

Retrieval Methodology

Cloud top height determined from VIS (532 nm) backscatter time-of-flight and discrimination of ice-water phase using depolarization. Noise is reduced by horizontal averaging at multiple resolutions.

Ancillary Input

  • GMAO profiles
  • References

  • Winker, D. M., M. A. Vaughan, A. H. Omar, Y. Hu, K. A. Powell, Z. Liu, W. H. Hunt, and S. A. Young, 2009: Overview of the CALIPSO Mission and CALIOP Data Processing Algorithms. J. Atmos. Oceanic Technol., 26, 2310-2323.
  • Hu, Y., D. Winker, M. Vaughan, B. Lin, A. Omar, C. Trepte, D. Flittner, P. Yang, W. Sun, Z. Liu, Z. Wang, S. Young, K. Stamnes, J. Huang, R. Kuehn, B. Baum and R. Holz, 2009: CALIPSO/CALIOP Cloud Phase Discrimination Algorithm, J. Atmos. Oceanic Technol., 26, 2293-2309, doi:10.1175/2009JTECHA1280.1.
  • Vaughan, M., K. Powell, R. Kuehn, S. Young, D. Winker, C. Hostetler, W. Hunt, Z. Liu, M. McGill, B. Getzewich, 2009: Fully Automated Detection of Cloud and Aerosol Layers in the CALIPSO Lidar Measurements, J. Atmos. Oceanic Technol., 26, 2034-2050, doi: 10.1175/2009JTECHA1228.1
  • Winker, D. M., J. Pelon, J. A. Coakley, Jr., and co-authors, 2010: The CALIPSO Mission: A Global 3D View Of Aerosols And Clouds, Bull. Amer. Meteorol. Soc., 91, 1211-1229, doi:10.1175/2010BAMS3009.1.