Hannover 2003 – scientific programme

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UP: Umweltphysik

UP 5: Atmosphäre und Klima

UP 5.1: Talk

Friday, March 28, 2003, 11:30–11:45, TIB

Optical thickness of clouds derived from SeaWiFs Imagery — •ALEXANDER KOKHANOVSKY und Wolfgang von Hoyningen-Huene — Bremen University, Otto Hahn Allee 1, 28334 Bremen

The paper is devoted to an application of a semi-analytical cloud retrieval algorithm(SACRA) to the SeaWiFs imagery. The algorithm is largely based on the asymptotic radiative transfer theory, valid for optically thick clouds with optical thickness larger than approximately 5. This includes most of warm cloud situations. It is assumed that effective radius of droplets is equal to 10 microns. However, this assumption does not influence very much the retrieval results due to a low sensitivity of the cloud reflection function to the size of droplets(for a constant optical thickness). The SACRA applied to the SeaWiFs imagery for selected regions of Western Europe and Atlantic ocean. Found values of the optical thickness are consistent with values characteristic for cloud systems studied(stratus clouds and hurricanes). Also the aerosol optical thickness around cloud fields is retrieved, using the look-up table approach. Results obtained can be used for aerosol-cloud interaction and cloud dynamics studies.