Recorded presentation9.3
Intercomparisons of cloud top and bottom heights from CALIPSO, CloudSat, MODIS, and ground-based LIDAR
Soon-Chang Yoon, School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea; and K. C. Moon, S. W. Kim, and E. S. Chung
This study presents results of the intercomparison of cloud top and bottom heights (CTH and CBH) obtained from a space-borne active sensor Cloud Profiling Radar (CPR), and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), the space-borne passive sensor Moderate Resolution Imaging Spectroradiometer (MODIS), and ground-based lidar measurements. Three selected cases (one daytime and two night-time cases) involving various cloud conditions such as semi-transparent thin cirrus, opaque thick tropospheric clouds, and multi-layered clouds are studied. The space-based CALIOP provides reliable information on the vertical structure of thin high-altitude cirrus clouds containing small ice particles, but the CPR has low sensitivity to these clouds due to the use of different wavelength. The CTHs retrieved from the CPR and CALIOP for thick tropospheric clouds are in good agreement with each other. Discrepancies between the CPR and the CALIOP values of the CBH for thick opaque clouds arise from strong lidar signal attenuations. In cloud overlap conditions (i.e., multi-layered clouds are present), the CALIOP has difficulties in determining the cloud vertical structure (CVS) for thick clouds underlying thin cirrus clouds due to signal attenuations, whereas the CPR detects the CTH and CBH of both the cloud layers. The CBHs derived from the CPR and ground-based lidar are generally in good agreement with each other. The ability of the MODIS to determine the CTH is limited due to the nature of infrared-based passive measurements on satellites, especially for optically thin high-altitude cirrus clouds and lower tropospheric clouds.
Session 9, Satelite Studies and Lidar Observations - II
Thursday, 15 January 2009, 11:00 AM-12:00 PM, Room 122A
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