Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 4 2007 10.5194/acpd-7-11207-2007 http://www.atmos-chem-phys-discuss.net/7/11207/2007/ http://www.atmos-chem-phys-discuss.net/7/11207/2007/acpd-7-11207-2007.html http://www.atmos-chem-phys-discuss.net/7/11207/2007/acpd-7-11207-2007.pdf 11207 11222 2007-08-01 Validation of aerosol and cloud layer structures from the space-borne lidar CALIOP using Seoul National University ground-based lidar S.-W. Kim sang-woo.kim@cea.fr S. Berthier P. Chazette J.-C. Raut F. Dulac S.-C. Yoon Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, Gif-Sur-Yvette, France School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea We present first observationally based validations of the space-borne lidar CALIOP onboard CALIPSO satellite using coincidental observations from a ground-based SNU lidar for 3 different types of atmospheric scenes. Both lidar measurements were taken in nearly same airmass in space and time. Total attenuated backscatters at 532 nm from the two instruments show similar aerosol and cloud layer structures (the top and bottom heights) both under cloud-free conditions and in case of multi-aerosol layers underlying semi-transparent cirrus clouds. This result confirms that the CALIPSO science team algorithms of the discrimination of cloud and aerosol as well as of their layer top and base altitudes are sound. Under thick clouds conditions, only information on the cloud top (bottom) height is reliable from CALIOP (ground-based lidar) observations due to strong signal attenuations. However, simultaneous space-borne CALIOP and ground-based SNU lidar measurements complement each other and provide full information on the vertical distribution of aerosols and clouds. 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