HR: 17:45h
AN: A34D-08    [Abstracts]
TI: Ship based cloud and radiation measurements on the Atlantic Ocean
AU: Macke, A
EM: amacke@ifm-geomar.de
AF: IFM-GEOMAR, Duesternbrooker Weg 20, 24105, Kiel, Germany
AU: * Kalisch, J
EM: jkalisch@ifm-geomar.de
AF: IFM-GEOMAR, Duesternbrooker Weg 20, 24105, Kiel, Germany
AU: Hollmann, R
EM: Rainer.Hollmann@dwd.de
AF: DWD, Kaiserleistr. 29/35, Offenbach, 63067, Germany
AU: Sinitsyn, A
EM: sinitsyn@passat.sail.msk.ru
AF: IORAS, 36 Nakhimovsky ave, Moscow, 117851, Russian Federation
AU: Wassmann, A
EM: awassmann@ifm-geomar.de
AF: IFM-GEOMAR, Duesternbrooker Weg 20, 24105, Kiel, Germany
AB: Clouds remain one of the biggest obstacles in our understanding of the coupled ocean-atmosphere climate system. Because of the strong inhomogeneity of cloud pattern on those scales that are relevant for the radiative transfer processes it is clear that subgrid-scale processes must be accounted for in radiative transfer parameterizations. Combined observations of cloud physical and radiative properties are a key to adjust or to validate such parameterizations. In spring and in fall 2007 the cruises ANT-XXIII-10 and ANT-XXIV-1 of the German research vessel Polarstern from South Africa to Germany and back have been utilized to perform continuous measurements of the radiation budget at the sea surface and the corresponding cloud properties under tropical, subtropical and mid-latitude climate conditions. For the first time, a multichannel microwave radiometer has been operated under open ocean conditions to obtain profiles of humidity, temperature, as well as liquid water path and water vapor path with 1 Hz temporal resolution. Cloud cover, cloud type and cloud bottom height have been obtained from continuous sky imaging and ceilometer measurements. Satellite based surface radiation budget estimates from Meteosat-7 SEVIRI measurements provided by the Climate Monitoring - Satellite Application Facilities CM-SAF have been compared to ship based measurements. Differences between the two will be discussed in terms of climatological and meteorological conditions. The high resolution ship based observations of cloud and radiation properties have been applied to improve exisiting surface radiation parameterizations with special considerations of rapid fluctuations due to the dynamics of clouds. Both campaigns in 2007 are test phases for the German national project OCEANET where temporarilly high resolved measurements of the chemical and biological composition of the upper ocean are combined with energy- and CO2-flux measurements at the ocean surface to improve our understanding of ocean-atmosphere interactions. To this end intensive measurements during six Atlantic transects of RV Polarstern between 2008 and 2010 will be performed.
DE: 0321 Cloud/radiation interaction
DE: 0360 Radiation: transmission and scattering
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting