An Initial Assessment of CALIPSO Antarctic Polar Stratospheric Cloud Observations

Routine operations of instruments onboard the CALIPSO spacecraft began in early June 2006. The spacecraft is in a sun-synchronous orbit, meaning that along-track data from the onboard lidar system CALIOP (Cloud- Aerosol LIdar with Orthogonal Polarization) are collected at latitudes up to about 82 degrees in both hemispheres continuously during every orbit. Therefore, extensive measurements have been obtained in the Antarctic polar vortex during the time of year when polar stratospheric clouds (PSCs) are present. The CALIOP data are collected in 3 receiver channels: 1064-nm total backscatter, 532-nm parallel-polarized backscatter, and 532-nm perpendicular-polarized backscatter. Past analyses of similar multi-channel data from ground-based and airborne lidar systems operating during polar winter have revealed many details on PSC formation and evolution, e.g. that PSC particles occur in both liquid (supercooled ternary solution) and solid (nitric acid trihydrate and water ice) forms. This talk will discuss CALIOP observations of PSCs during the 2006 Antarctic season in the context of these earlier studies and provide an initial assessment of the ability to extract PSC microphysical information such as particle composition from the CALIOP data.