How Storms in the German Bight Have Changed

The German Bight stretches from the West Frisian Islands in the Netherlands and North Frisian Islands in Germany to the Danish Wadden Sea Islands. Storms here aren’t uncommon. But does that mean that nothing has changed, or have the storms recently become more frequent and more severe?

Meteorologist Daniel Krieger investigated this question for his master’s thesis. In 2020, he won third prize in the Young Climate Scientists Award for his research.

At sea, the wind can blow across the water unhindered – while on land, mountains, forests and buildings make it virtually impossible to measure reliably. In order to draw conclusions about past storm climates, meteorologists often rely on atmospheric pressure data. If the atmospheric pressure at various sites and at the same point in time is known, the occurrence and intensity of the wind can be determined.

For his master’s dissertation, Krieger used pressure data from eight German, Dutch and Danish measuring stations in the German Bight. On paper, he connected the dots between the stations to create various overlapping triangles, with each station forming a corner. Using the available data, he was able to calculate the wind conditions in the area represented by each triangle. This is a more reliable approach than previous efforts, which only investigated individual triangles or larger areas.  

Krieger’s study shows that storm activity has fluctuated since the beginning of record-keeping, 120 years ago – as long as atmospheric pressure has been recorded at the various stations. Every three to four decades, there is a relatively stormy period; the rest of the time, it’s calm. Overall, the storm climate can be described as being consistently wave-like. According to Krieger, “Since 1897, storm activity has neither increased nor decreased. There isn’t a trend, contrary to what climate change and the corresponding increase in extreme weather events might lead us to assume.”

The meteorologist is now investigating the predictability of storms as part of his doctoral studies at the Helmholtz Centre for Materials and Coastal Research in Geesthacht. To do so, he employs various climate models, i.e., computer models that simulate and predict the future climate. In order to gauge the models’ reliability, Krieger starts the simulations in the past and compares their projections with actual climate records. In this regard, the data from his master’s thesis is a valuable resource for him and his team.