What CMIP6 Models Tell Us About the Impact of AMOC Variability on the Arctic

In this paper we address the question whether variability in the Atlantic Meridional Overturning Circulation (AMOC) and its associated heat transport at mid-latitudes impacts the Arctic Earth system. To that end, we perform coherence analysis on time series of ocean heat transport, AMOC strength, and Arctic climate metrics across a large number of models from the CMIP6 ensemble. We find that, on multidecadal timescales, the majority of CMIP6 models indeed display a statistically significant relationship between AMOC at mid-latitudes (45 °N) and metrics like Arctic surface air temperatures and sea ice. However, our results do not support the narrative that heat transport anomalies at lower latitudes propagate northward toward the Arctic. Instead, our results confirm that variability in meridional ocean heat transport arises in the subpolar North Atlantic and propagates southward and northward.. Authors: Weijer, Wilbert [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); University of Alaska, Fairbanks, AK (United States)] (ORCID:000000025654562X); Huo, Yiling [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000218888015); Garuba, Oluwayemi [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000179317788); Lee, Younjoo [Naval Postgraduate School, Monterey, CA (United States)] (ORCID:0000000228699680); Molodtsov, Sergey [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)]. DOE Contract: 89243019SSC000030; AC05-76RL01830. Subjects: Arctic Ocean warming; Atlantic Meridional Overturning Circulation; CMIP6