NP Nonlinear Processes in Geosciences
The 2022 Outstanding Student and PhD candidate Presentation (OSPP) Award is awarded to Lana Blaschke for the poster/PICO entitled:
AMOC early warning signals in CMIP6 models? (Blaschke, L.; Ben-Yami, M.; Boers, N.; Nian, D.)
Click here to download the poster/PICO file.
Lana Blaschke is a PhD student at the Potsdam Institute for Climate Impact Research (PIK) and the Technical University of Munich (TUM), Germany.
In the group led by Professor Niklas Boers she focuses on resilience of Tipping Elements, such as the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rain forest. Theory suggests that abrupt transitions in such systems are preceded by critical slowing down (CSD) and indicators of CSD can serve as early warning signals.
The work presented at EGU22 analyses fingerprints of the AMOC from the runs of the Coupled Model Intercomparison Project Phase 6 (CMIP6), and focuses on indicators of CSD. Whilst fingerprints based on sea-surface temperature (SST) observations show a decreasing trend in the historical periods, the AMOC fingerprints in the models show both increasing and decreasing trends. The large spread in trend is present even in ensemble members of the same model. This might be due to internal multi-centennial oscillations of the AMOC instead of the external forcing.
In addition, whilst the observed SST-based fingerprint shows significant indicators of CSD, no such significant indicators are found in CMIP6. This could be because of imperfect model representations of the AMOC in CMIP6, a separate destabilization of the AMOC subsystems, or by the over-simplification of the 1-dimensional fingerprints.