Polar climate change
global ocean impacts
"Explorers are we, intrepid and bold, out in the wild, amongst wonders untold."
[The Indispensable Calvin and Hobbes, Bill Watterson]
co-lead of the Southern Ocean Freshwater Input from Antarctica (SOFIA) initiative
Antarctica InSync national committee member, lead of modelling working group
member of CLIVAR/CliC/SCAR Southern Ocean Region Panel (SORP) [co-chair 2020-2023]
member of GRISO working group Ice Forcing Ocean around Greenland
POF-IV subtopic 2.3 sea level change center representative
student advisor in physical oceanography
member of GEOMAR scientific council
session chair at EGU General Assembly and other international conferences
project principle investigator
Research
I am fascinated by the ocean and its interaction with ice; I study mostly dynamical processes; I am curious about mechanisms bridging and linking scales from a few hundred meters to thousands of kilometers, from months to centennials.
My research focusses on marine climate variability in both northern and southern high latitudes and related teleconnections. Themes catching my interest:
melting ice: Arctic sea ice retreats, Greenland's and Antarctica's ice sheets melt, and thus the ocean underneath, adjacent and beyond is forced to adjust. How does this adjustment look like and what are the consequences?
ocean-ice-atmosphere dynamics: Interaction and feedbacks between these climate components in subpolar regions impact the overturning circulation of the ocean, which plays a key role in global heat redistribution. How do these feedbacks play out under rapid climate change?
ocean eddies: The ocean is much more than a simple 'conveyor belt' and mesoscale (10-100km) eddies play a key role in redistributing heat and freshwater. Do climate models resolving these fetures respond differently to global warming?
ocean extremes: While extreme weather is well known to everyone, ocean extremes have only recently attracted attention. Do rapid changes in ice melt trigger ocean extremes? Does the ocean have a memory for extremes?
deep AMOC: Formation of deep and bottom water in Atlantic sector subpolar regions is strongly influenced by ocean-ice-atmosphere interaction and drives the Atlantic Meridional Overturning Circulation (AMOC) with competing influence on its strength. How does the ocean translate rapid change at the surfaec to low frequent variability in the deep?
My research is based on global climate modelling with particular focus on ocean and ice components. Besides applying such models to particular research questions, I am actively involved in their development and continuous improvement. I do care about the exchange with the observational community knowing that only by complementing each other we improve the understanding of ocean and climate processes.
Teaching and more
traditional
innovative
fascinating
engaging
Teaching and supervising students is a valuable and fun part of my work. Being reminded of the fundamentals of, for instance, ocean dynamics while working on advanced research foci with complex models helps maintaining a broader picture of the climate system.
Being involved with teaching, I discovered a new playing field: rotating tank experiments. Next to solving classic problems of the hydrodynamic equations analytically on the board and simple computer-based modeling, these provide a third way of connecting with atmosphere and ocean dynamics. Also, it's simply a humongous amount of fun to "play" with water, food coloring and ice cubes and—as a side kick—see the equations on the board unfold in the "little desk ocean".
Our experience and advances we share on a blog and at international meetings. The project has drawn quite some attention university wide and also led to a collaboration with the DIYnamics group who triggered our initiative by publishing their detailed instructions of a Lego-driven turntable.
On a different note, I was co-chair of the Southern Ocean Region Panel (SORP) of CLIVAR, CliC and SCAR from April 2020 to December 2023. During this time we successfully navigated the panel through the difficult period of the COVID-19 pandemic managing monthly online video calls across time zones. Key achievemnts were the initiation of the Southern Ocean Freshwater Input from Antarctica (SOFIA) initiative, contributions to the Southern Ocean United Nations Decade action plan, a workshop on polar freshwater co-organized with NORP, a summer school on polar climates in Trieste, Italy co-organized with ICTP and NORP, and a paper collection on emerging Antarctic/Southern Ocean programs published in CLIVAR Exchanges.
I am also regularly chairing sessions at international meetings and co-organizing workshops on, for example, the Southern Ocean, ice-ocean interaction and high-resolution ocean modeling. [EGU 2019, 2021, 2022, 2023, 2024; OSM 2016, 2022]