Joint Seminar: Joint response of Euro-Atlantic sea surface temperatures to external forcing
The European seas have been among the strongest warming seas in the world during the last
decades. Studies indicate that one driver of the exceptional warming was the North Atlantic, in
particular the Atlantic Multidecadal Variability (AMV). However, those studies do not thoroughly
separate internal variability and externally forced climate responses. We aim to achieve such a
separation by employing so-called Single-Model Initial-condition Large Ensembles (SMILEs). A SMILE
consists of multiple runs of a (global) climate model which use the same forcing, but start from
different initial conditions. Thus, each ensemble member evolves with a distinct realization of
internal variability whereas the response to external forcing is similar and can be extracted by
computing the ensemble mean. In our study, we analyze both historical (1850-2014) and scenario
(2015-2100) runs performed with two SMILEs under CMIP6. We find that the presumed impact of the
AMV on the regional SSTs arises mainly from a simultaneous response of the North Atlantic and
European SSTs to external forcing. However, the coherence of those externally forced responses is
time-dependent and apparently linked to changes in shortwave downward radiation which implies a
connection to anthropogenic aerosol emissions. As a next step, we plan to further explore the
importance of different external drivers for the low-frequency variability of European climate by
analyzing single-forcing experiments
Datum
03.12.2025
Uhrzeit
13:30 h
Ort
- Bundesstr. 53, room 022/023
- Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg
Chair
- Sebastian Brune