1Leibniz-Institute for Tropospheric Research (TROPOS), Permoserstraße 15, 04318 Leipzig, Germany
2European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), Darmstadt, Germany
Received: 28 Feb 2012 – Published in Atmos. Chem. Phys. Discuss.: 19 Jul 2012
Abstract. In this study the shortwave cloud radiative effect (SWCRE) over ocean calculated by the ECHAM 5 climate model is evaluated for the cloud property input derived from ship based measurements and satellite based estimates and compared to ship based radiation measurements. The ship observations yield cloud fraction, liquid water path from a microwave radiometer, cloud bottom height as well as temperature and humidity profiles from radiosonde ascents. Level-2 products of the Satellite Application Facility on Climate Monitoring (CM~SAF) from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) have been used to characterize clouds. Within a closure study six different experiments have been defined to find the optimal set of measurements to calculate downward shortwave radiation (DSR) and the SWCRE from the model, and their results have been evaluated under seven different synoptic situations. Four of these experiments are defined to investigate the advantage of including the satellite-based cloud droplet effective radius as additional cloud property. The modeled SWCRE based on satellite retrieved cloud properties has a comparable accuracy to the modeled SWCRE based on ship data. For several cases, an improvement through introducing the satellite-based estimate of effective radius as additional information to the ship based data was found. Due to their different measuring characteristics, however, each dataset shows best results for different atmospheric conditions.
Revised: 29 Nov 2012 – Accepted: 10 Dec 2012 – Published: 21 Dec 2012
Citation: Hanschmann, T., Deneke, H., Roebeling, R., and Macke, A.: Evaluation of the shortwave cloud radiative effect over the ocean by use of ship and satellite observations, Atmos. Chem. Phys., 12, 12243-12253, doi:10.5194/acp-12-12243-2012, 2012.