Joint Seminar: Modelling the ocean across climate states and resolutons
When modelling Earth’s climate, the relevant spatial and temporal scales differ between research questions. In this talk, we will see examples of how models of different resolutions and complexity can teach us about the ocean’s role in the climate system across different climate states. The talk is divided into two parts. In the first part, we focus on global ocean storage of dissolved inorganic carbon (DIC), which shows strong variability across climate states, and explore the role of the global ocean overturning circulation in this variability. We perform a sensitivity study in the intermediate complexity Earth System model cGENIE, and we explore historical and future simulations with the comprehensive Earth System model CESM2. In equilibrium simulations with cGENIE, stronger ocean overturning leads to less ocean storage of DIC, and vice versa. However, in the transient simulations with CESM2, the relationship between ocean overturning strength and carbon storage is less straightforward. We clarify the effect of changes in ocean overturning strength on the biological and solubility carbon pumps, respectively, in our range of studied simulations. In the second part, we focus on the Atlantic sector of the Southern Ocean and the impact of increased ocean resolution in this region in the global coupled climate model FOCI. When going from a resolution with parameterised eddies (1/2˚) to an eddy-rich ocean (1/10˚), we find marked changes in the ocean distribution and transport of heat originating from the Agulhas retroflection. This leads to coupled climate effects (e.g., precipitation, winds) in and beyond the region with increased resolution. We see improved atmospheric biases in the tropical Atlantic in a 1950s control simulation, and a more pronounced seasonal cycle in the position of the Southern Hemisphere westerly wind band in a scenario with strong global warming. This suggests that increased ocean resolution in key regions can play an important role in simulating global climate and its response to anthropogenic CO2.
Datum
11.09.2024
Uhrzeit
13:30–15:00 h
Ort
- Bundesstr. 53, room 022/023
- Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg
Chair
- Marlene Klockmann