MEPS 156:263-273 (1997)  -  doi:10.3354/meps156263

Meteorological and oceanographic situation in the German Bight from 23 to 29 April 1991

Corinna Schrum1,*, Peter König2, Kirsten Michaelsen3, Ulrike Niemeier3, Thomas Pohlmann1

1Zentrum für Meeres- und Klimaforschung der Universität Hamburg, Institut für Meereskunde, Troplowitzstr. 7, D-22529 Hamburg, Germany
2Bundesamt für Seeschiffahrt und Hydrographie, Bernhard-Nocht-Str. 78, D-20359 Hamburg, Germany
3Zentrum für Meeres- und Klimaforschung der Universität Hamburg, Institut für Meteorologie, Bundesstr. 55, D-20146 Hamburg, Germany

The meteorological and oceanographic situation during a 6 d drift experiment in the German Bight at the end of April 1991 is evaluated by combining field data, observation network data and results of different numerical models. By combining all available data, it was possible to represent the complex state of the physical situation during the course of the drift experiment and to gain essential information for the interpretation of chemical and biological measurements performed during the drift experiment. This examination shows that the drift experiment can be subdivided into 2 parts. During the first part the situation was dominated by a high pressure system over Scandinavia. This high was associated with weak easterly winds which transported polluted air masses into the region of the experiment. The prevailing easterly winds led to a strong vertical shear in the oceanic circulation between the upper water levels. This shear caused water masses of different origin to coincide within the drift experiment region. During the second phase the region was influenced by a low which led to precipitation and thereby to a washout of contaminants from the atmosphere. Under the influence of the prevailing northerly winds during the second phase, the vertical shear of the oceanic circulation diminished and a cyclonic circulation established itself over the whole water column, as model results showed.

North Sea · German Bight · Drift experiment · Numerical modelling

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