Aerosol-forced AMOC changes in CMIP6 historical simulations.
- 1LOCEAN, Sorbonne Université, Paris, France
- 2NCAS, Department of Meteorology, University of Reading, UK
- 3Department of Meteorology, University of Reading, UK
- 4Met Office Hadley Centre, Met Office, Exeter, UK
- 5CECI CNRS-Cerfacs, Toulouse, France
- 6NCAS, School of Earth and the Environment, University of Leeds, UK
- 7NOAA/GFDL, Princeton, USA
The Atlantic Meridional Overturning Circulation (AMOC) has been, and will continue to be, a key factor in the modulation of climate change both locally and globally. Reliable simulations of its decadal to century-timescale evolution are key to providing skilful predictions of future regional climate, and to understanding the likelihood of a potential AMOC collapse. However, there remains considerable uncertainty even in past AMOC evolution. Here, we show that the multi-model mean AMOC strengthened by approximately 10% to 1985 in new historical simulations for the 6th Coupled Model Inter-comparison Project (CMIP6), contrary to results obtained from CMIP5. The simulated strengthening is due to a stronger anthropogenic aerosol forcing, in particular due to aerosol-cloud interactions. However, comparison with an observed sea surface temperature fingerprint of AMOC evolution during 1850-1985, and the shortwave forcing during 1985-2014, suggest that anthropogenic forcing and the subsequent AMOC response may be overestimated in some CMIP6 models.
How to cite: Menary, M., Robson, J., Allan, R., Booth, B., Cassou, C., Gastineau, G., Gregory, J., Hodson, D., Jones, C., Mignot, J., Ringer, M., Sutton, R., Wilcox, L., and Zhang, R.: Aerosol-forced AMOC changes in CMIP6 historical simulations., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2379, https://doi.org/10.5194/egusphere-egu2020-2379, 2020.