EGU25-14770, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-14770
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Underestimated trends of Amundsen Sea Low associated with unrealistic interdecadal tropical variability in CMIP6 models
Donglin Cai
Donglin Cai
  • Ocean University of China, China (maggie_bn@126.com)

The Amundsen Sea Low (ASL) is a connection between the tropical variabilities and climate changes in the Antarctic. The combination of negative trend of the Interdecadal Pacific Oscillation (IPO) and the positive trend of the Atlantic Multidecadal Oscillation (AMO) is recognized to result in the strengthening of the Amundsen Sea Low (ASL) as well as the change of the Antarctic sea ice in recent decades. In this study, we demonstrate that models in the Coupled Model Intercomparison Project phase 6 (CMIP6) largely underestimate the combined influence of IPO and AMO on the ASL variability. The unrealistic relationship between IPO and AMO among coupled models, which potentially cancels out their effects on the ASL each other, is one potential factor for the underestimated ASL variability. Another factor is the large inconsistent AMO-related teleconnection patterns among models. Further analysis is carried out to explore the origin of the large model spread, and the result suggests that the cool mean SST biases over the northern tropical Atlantic Ocean and the warm mean SST biases over the southeastern Pacific are both found to be the dominant source for the underestimated ASL change. These results emphasize the collaborative effect of the IPO and AMO to the Southern Ocean region and the related model biases among the coupled models.   

How to cite: Cai, D.: Underestimated trends of Amundsen Sea Low associated with unrealistic interdecadal tropical variability in CMIP6 models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14770, https://doi.org/10.5194/egusphere-egu25-14770, 2025.