Sea-level oscillations with 6-h period in the North Sea 29-31 October 2000. An analysis of data from stations in the northern North Sea and along the western coast of Norway

摘要

During the storm event 29-31 October 2000 long regular trains of residual sea-level oscillations with period about 6 h occurred in the North Sea area. Crest-to-trough heights up to 0.8 m were observed along the western coast of Norway. Model simulations show that these oscillations were mainly due to spatial and temporal variations in the atmospheric forcing and were not the result of nonlinear tide-surge interaction. The oscillations propagated northwards along the Norwegian coast and the signal was amplified in some fjords in agreement with predictions by high-resolution regional models. In Skagerrak in the north eastern North Sea the main storm-surge signal appeared as amplitude-modulated oscillations with period about 12 h and crest-to-trough height up to 1.5 m. Here the tide-surge interaction contributed up to about 20% of the peak surge. On the coast of Scotland and in the southern part of the North Sea nonlinear effects produced oscillations with 6-h period at some stations.