HR: 17:00h
AN: A14A-05    [Abstracts]
TI: Intercomparison of cloud properties derived from MODIS and METEOSAT-SEVIRI
AU: * Deneke, H
EM: deneke@knmi.nl
AF: Royal Netherlands Meteorological Institute, Wilhelminalaan 10, De Bilt, 3732GK, Netherlands
AU: * Deneke, H
EM: deneke@knmi.nl
AF: Meteorological Institute, University of Bonn, Auf dem Hà¼gel 20, Bonn, 53121, Germany
AU: Roebeling, R
EM: roebelin@knmi.nl
AF: Royal Netherlands Meteorological Institute, Wilhelminalaan 10, De Bilt, 3732GK, Netherlands
AU: Wolters, E
EM: wolterse@knmi.nl
AF: Royal Netherlands Meteorological Institute, Wilhelminalaan 10, De Bilt, 3732GK, Netherlands
AU: Feijt, A
EM: feijt@knmi.nl
AF: Royal Netherlands Meteorological Institute, Wilhelminalaan 10, De Bilt, 3732GK, Netherlands
AB: Cloud properties inferred from meteorological satellite imagers provide an important reference for the evaluation of cloud processes and cloud-radiation interactions in climate and weather prediction models. To date, the MODIS instrument on board the polar-orbiting TERRA and AQUA satellites offers a unique data source, due to the large number of spectral channels, the high spatial resolution, and the accurate on-board calibration. In contrast to polar orbiters, geostationary satellite provide regular and frequent sampling, and are thus better suited to monitor the development of clouds and resolve their diurnal cycle. EUMETSAT operates the METEOSAT series of geostationary satellites, which provide full-disk images covering Europe and Africa at 15 minute intervals. However, users have to sacrifice some accuracy in comparison to MODIS, due to fewer and wider spectral channels, coarser resolution, and a lower calibration accuracy. To stimulate the use of METEOSAT data in the scientific community, several satellite application facilities have been initiated at European national weather services. Within the Satellite Application Facility on Climate Monitoring, the Royal Netherlands Meteorological Institute (KNMI) has developed retrievals of cloud thermodynamic phase, optical thickness, effective radius and water path. As part of the validation activities, a detailed comparison of these cloud products to corresponding MODIS products has been carried out and is presented here. Special attention is given to the various mechanisms responsible for the observed differences, and their individual contributions to the combined deviations. These include the algorithms themselves, differing spatial resolution and viewing geometry, and discrepancies in sensor calibration and spectral response. In particular, the dependence on sensor resolution and the effects of partially filled pixels on derived cloud properties are studied. A thorough understanding of these mechanisms is of central importance for the interpretation of observed discrepancies between different satellite-based cloud datasets, and their relevance for model validation studies.
DE: 0321 Cloud/radiation interaction
DE: 3310 Clouds and cloud feedbacks
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting