Evaluation of the Arctic Atmospheric Circulation in CMIP6

The Arctic atmospheric circulation is expected to undergo changes across the 21^st Century due to the impacts of the deviations in the global climate including Arctic Amplification and reductions in Arctic sea ice. These changes in atmospheric circulation are predicted to have significant impacts in areas such as coastal erosion, Arctic shipping, and Arctic-mid-latitude connections. The changes in Arctic atmospheric circulation in eight CMIP6 earth system models (ESMs) will be evaluated using the method of Self Organizing Maps (SOMs). The SOM technique will be used to objectively identify Arctic circulation patterns, based on sea level pressure, present in ERA5, MERRA2, and the eight CMIP6 ESMs data; and to document the frequency with which each pattern occurs in these datasets. An ensemble of the eight ESMs will also be included in the analyses. The CMIP6 data will include the historical period (1985-2014) and end-of-century (2071-2100) future ssp585 scenario. Each of the CMIP6 models will be compared to ERA5 to assess replicability of the frequency of each of the patterns in the SOM in the historical period. The results indicate which ESMs do well and which do poorly in depicting the atmospheric circulation of the Arctic for the historical period. An inter-model comparison will then be presented on the predicted changes in the Arctic atmospheric circulation at the end of the 21^st century. The results indicate how each CMIP6 ESM changes its Arctic atmospheric circulation patterns from the beginning to the end of the 21^st century.