Outstanding Bachelor Thesis on Ocean Modelling

The Marine Meteorology research unit investigates the Earth’s climate, in which the ocean plays a crucial role. High-resolution computer models are used to simulate ocean currents and eddies, and to analyse how the ocean responds to atmospheric influences. The finer the resolution required, the more computing power is needed, which also increases costs. Therefore, it is always about finding a resolution that is fine enough yet sufficiently realistic.

For his bachelor’s thesis, Lasse Kummer, a graduate of the Physics of the Earth System programme at Kiel University, utilised the NEMO (Nucleus for European Modelling of the Ocean) model to explore how varying resolutions affect the representation of ocean circulation. His focus was on smaller structures such as ocean eddies and western boundary currents in the North Atlantic, which are crucial for the model’s accuracy. Kummer analysed an idealised “double-gyre circulation” in five model experiments with different resolutions. He summarised his findings in his bachelor’s thesis titled “Representation of double-gyre circulations in ocean models of varying horizontal resolutions”.

For his overall excellent bachelor’s degree, the young scientist was awarded the Otto-Krümmel Prize by the “Society to Support GEOMAR Helmholtz Centre for Ocean Research Kiel” today. The award, endowed with €1,500, is jointly funded by the Society and the Briese shipping company.

“Mr Kummer's work demonstrates that students can achieve remarkable scientific accomplishments early in their academic careers,” said Dr Peter Gimpel, Chairman of the Society. “With the Otto-Krümmel Prize, we aim to recognise this and bring the bachelor’s degree, which is often undervalued in the natural sciences, into the spotlight.”

“The Otto-Krümmel Prize is a great recognition for young researchers,” said GEOMAR Director Professor Dr Katja Matthes. “We award it during our internal Science Day at the Centre and deliberately make it part of our scientific exchange.” Addressing the laureate, she added: “This prize acknowledges your outstanding achievement, and I hope it motivates you to continue your scientific journey with enthusiasm.”

Lasse Kummer has been studying Physics of the Earth System at Christian-Albrechts-University of Kiel (CAU) since 2020, and is currently enrolled in the Climate Physics programme. He completed his thesis in the Marine Meteorology Research Unit in the Ocean Circulation and Climate Dynamics Research Division at GEOMAR, supervised by Dr Malin Ödalen and Professor Dr Joakim Kjellsson. The latter expressed his admiration: “In addition to completing all the planned tasks, Lasse Kummer conducted additional analyses to verify the realism of the simulations. His results provide valuable insights into the advantages and limitations of various model configurations and help us better understand the impacts of finer grid resolutions.”

The goal was not to create the most realistic model but to investigate the effects of varying resolutions. Kummer found that higher resolutions lead to increasingly turbulent flows that affect the overall circulation. Notably, larger eddies alter the direction of currents and impact heat transport in the ocean. A higher resolution can thus better represent both the mean ocean state and the variability in variables such as heat transport.

Models with lower resolution, while less realistic, are mathematically easier to understand and describe. Due to their mathematical simplicity, these models, despite their imperfections, contribute to a deeper understanding of the fundamental mechanisms relevant to more complex models.

“The analysis scripts developed in this work are already being used by other researchers and will remain valuable tools in the future,” said Joakim Kjellsson appreciatively. “A colleague summed it up perfectly when he asked if it was a Master’s thesis – no, it’s a Bachelor’s thesis, an excellent one!”

About the Otto Krümmel Prize:

Since 2016, the “Society to Support GEOMAR Helmholtz Centre for Ocean Research Kiel e.V.” has annually awarded the Otto Krümmel Prize. The award recognises outstanding bachelor’s degrees  in the field of ocean research. Applicants must have graduated within the last year from a German university, awarded with the grade “outstanding” or “very good.” All disciplines of marine research, including marine technology, are invited. The selection of prize winners is made by an independent committee, which includes external scientists. The prize is endowed with €1,500, funded equally by the Society and the Briese shipping company.

About Otto Krümmel:

Professor Dr Otto Krümmel (1854-1912) is considered the founder of general oceanography in Germany. He taught and worked primarily in Kiel. Krümmel’s ideas about the structure of the seabed were groundbreaking. His work includes around 100 publications covering almost all areas of general geography, oceanography, and hydrographic measurement technology. Through his interdisciplinary research, he gained international recognition and, along with other researchers, advocated for international collaboration in marine research. These efforts led to the establishment of the “International Council for the Exploration of the Sea” in 1902, a state-coordinated scientific association.