Comparison between ATSR-2 stereo, MOS O2-A band and ground-based cloud top heights
Abstract:A new method to retrieve cloud top heights stereoscopically using the dual-view facility of the Along Track Scanning Radiometer 2 (ATSR-2) instrument is assessed. This assessment is performed through a comparison of the cloud top heights obtained from ATSR-2 stereo and those derived from a 94-GHz radar, radiosonde profiles and independently from the Modular Optoelectronic Scanner (MOS) using the O2-A band. The data for this study were collected over the United Kingdom from September 1998-March 1999. The results show that the accuracy of the ATSR-2 stereo heights is generally as predicted on theoretical grounds, with the errors in the 1.6 µm and 0.65 µm stereo heights rarely exceeding 2 km. Case study periods with disagreements between the ATSR-2 heights and the ground-based retrievals are often due to the lack of precise match-ups between the ground-based and satellite scenes, while the MOS O2-A band is shown sometimes to miss the tops of high clouds. Evidence that the 11 µm channel is more sensitive to high clouds than originally thought is given and a future application of multi-spectral stereo cloud top heights is proposed.
Document Type: Research Article
Affiliations: 1: now at Columbia University, NASA Goddard Institute for Space Studies, New York, NY 10025, USA,Department of Geomatic Engineering, University College London (UCL), London WC1E 6BT, UK 2: now at Mail Stop 183-601, Jet Propulsion Laboratory, Pasadena, CA, 91109-8099, USA,Department of Geomatic Engineering, University College London (UCL), London WC1E 6BT, UK 3: Department of Geomatic Engineering, University College London (UCL), London WC1E 6BT, UK,now at Department of Space and Climate Physics, MSSL, UCL, Dorking, Surrey, RH5 6NT, UK 4: Department of Meteorology, 603 Walker Building, Pennsylvania State University, University Park, PA 16802, USA 5: Free University of Berlin, Institut fur Weltraum-wissenschaften, D-14195 Berlin, Germany,now at Deutscher Wetterdienst (DWD), Dept. Climate and Environment, D-63067 Offenbach, Germany 6: Free University of Berlin, Institut fur Weltraum-wissenschaften, D-14195 Berlin, Germany 7: Department of Meteorology, University of Reading, Reading, Berkshire, RG6 6AH, UK
Publication date: 2007-05-01