Categorisation of Meteorological Conditions for Storm Tide Episodes in the German Bight

Abstract

The German North Sea coast is exposed to storm surges induced by typical weather situations. For this study, the weather situations of all observed storm tides between January 1949 and April 2012 were investigated. An overall number of 366 cases were identified, analysed and assigned to three categories: the North-West Type (NWT), the West and South-West Type (W+SWT) and the Iceland Gale Type (IGT). The number of occurrences of NWT situations was slightly smaller than that of W+SWT cases, and there were only a small number of IGT. Severe storm tides were induced in 51 of all cases. The investigation showed slightly more NWT than W+SWT cases, and no IGT case. Severe storm tides hit in almost every case all parts of the German North Sea coast. Storm tides affected more frequently the eastern part of German Bight than the southern part by a small amount. There were three storm surge seasons (September to April) without a storm tide and three with the maximum of ten episodes. On average, five storm tide episodes occurred per season. All time series of the frequencies of the specific weather types show a high inter-annual and decadal variability. Therefore, the detection of long-term trends is problematic in view of the relatively short length of time series of only 63 years.

Keywords

• storm tides
• German Bight
• storm surge weather conditions
• storm track