Weather forecasts: Obtaining a better understanding of processes in the atmospheric boundary layer

Thunderstorms, wind, fog, extreme rainfall – all these weather events develop in the near-surface layer of air in the earth's atmosphere. Quantifying the processes that occur in this layer using meteorological models is still problematic.

In order to improve its forecasts, over the next four years the German Meteorological Service will be sponsoring a new professorship for boundary layer meteorology at the Goethe University with the amount of 1.2 million euros.

The atmospheric boundary layer, up to one thousand metres thick, can attain altitudes comparable to that of the great Feldberg in the Taunus. This is where the exchange of humidity between the ground and the air occurs, triggering cloud formation, which in turn influences solar radiation.

The enhanced description of the boundary layer in numerical weather forecasting, especially in the corresponding models of the German Meteorological Service, promises more reliable forecasting of extreme weather events such as heavy rainfall. At the same time, it could also provide more precise predictions of near-ground winds and solar radiation for wind farms and solar facilities.

“Without a good description of the atmospheric boundary layer, an accurate weather forecast is impossible”, explains Prof. Ulrich Achatz of the Institute for Atmosphere and Environment at the Goethe University. It is particularly difficult to describe the boundary layer at night. During the day the ground is warmed up by solar radiation.

The associated drop in temperature from the ground up to greater atmospheric altitudes promotes the formation of turbulence that can be described relatively well. At night, the near-ground temperatures drop while the boundary layer is stabilised and experiences a complex interaction between turbulence and atmospheric waves. This is not taken sufficiently into consideration in the weather forecast programmes currently in use.

Along with the professorship, the positions of a post-doctoral fellow and two doctoral candidates are being sponsored by the Hans Ertel Centre of the German Meteorological Service (DWD), which is assigning one of its own staff members to work at the university for the duration of the sponsorship.

With this programme, which goes into its second sponsorship phase in 2015, the DWD is establishing research collaborations with German universities that are relevant for its own work. At the Goethe University, the new research field of boundary layer meteorology is being integrated into the course studies for the Bachelor's and Master's Programmes for Meteorology.

Information: Prof. Ulrich Achatz, Institute for Atmosphere and Environment, Phone +49 (0)69 798-40243, achatz@iau.uni-frankfurt.de

Goethe University is a research-oriented university in the European financial centre Frankfurt Founded in 1914 with purely private funds by liberally-oriented Frankfurt citizens, it is dedicated to research and education under the motto “Science for Society” and to this day continues to function as a “citizens’ university”. Many of the early benefactors were Jewish. Over the past 100 years, Goethe University has done pioneering work in the social and sociological sciences, chemistry, quantum physics, brain research and labour law. It gained a unique level of autonomy on 1 January 2008 by returning to its historic roots as a privately funded university. Today, it is among the top ten in external funding and among the top three largest universities in Germany, with three clusters of excellence in medicine, life sciences and the humanities.

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