The CALIPSO mission and initial results from CALIOP

Satellite lidars are now beginning to provide new capabilities for global atmospheric sensing from space. Following the Lidar In-space Technology Experiment (LITE), which flew on the Space Shuttle in 1994, and the Geoscience Laser Altimeter System (GLAS), which launched in 2003, the CALIPSO satellite was launched on April 28, 2006. Carrying a two-wavelength polarization lidar along with two passive imagers, CALIPSO is now providing unique measurements to improve our understanding of the role of aerosols and clouds in the Earth's climate system. The primary instrument on CALIPSO is CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization), a two-wavelength polarization lidar. Using a linearly polarized laser and a polarization-sensitive receiver, the instrument allows the discrimination of cloud ice/water phase and the identification of non-spherical aerosols. First light was achieved in June, 2006 and five months of nearly continuous observations have now been acquired. Initial performance assessments and calibration activities have been performed and instrument performance appears to be excellent. CALIPSO was developed within the framework of a collaboration between NASA and CNES.