ABSTRACT: 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.

KEY WORDS: North Sea · German Bight · Drift experiment · Numerical modelling

Published in MEPS Vol. 156 (1997) on September 25
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1997