29 June 2026: Ocean Circulation and Climate Dynamics Colloquium

When?  Monday 29 June 2026 at 11:00 h
Where?    Conference Room 5-1.214, Building 5, Wischhofstr. 1-3 and online
via Meeting link : https://geomar.webex.com/geomar-en/j.php?MTID=ma73a9dd4db0f5cb6275b471e1c5e6005

Abstract:
The radiation budget of the Earth is simultaneously modified by the effective radiative forcing and the radiative response to the forcing. Only the (im)balance between incoming and outgoing radiation can be observed. Therefore, we traditionally rely on climate models to estimate the contribution of forcing (e.g., emissions of greenhouse gases or volcanic eruptions) versus feedback (e.g., the radiative response to surface warming). Climate models come with biases and assumptions of cloud processes that are not understood well yet, so we want to make optimal use of observations to investigate the global energy budget. To do so, we utilize (explainable) artificial intelligence that can bridge the gap from models to observations. These approaches range from simple surrogates that estimate the global-mean radiative response to local surface temperature perturbations, to climate emulators that replicate the Earth's atmosphere based on reanalysis data.

We use these methods to estimate observation-based historical feedback and forcing and to investigate large-scale dynamical mechanisms influencing cloud feedbacks. We find that the global radiative feedback parameter had a minimum around 1982-2011 and has since been trending towards a less stable climate. Moreover, we predict an effective radiative forcing trend of 0.73±0.22 Wm-2 per decade for 2001-2025. Finally, we quantify how the stability of subtropical marine low clouds is influenced by sea surface temperature patterns and find both tropical and extratropical pathways to be important.

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