Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole

A mysteries graphic of sea surface temperatures is the kind of clickbait I fall for, apparently. As it turns out, a is the observations, b and c are from the models they're evaluating, referred to as AMOC- and AMOC+. d e and f are similar for salinity instead of temperature.

Looking at SST anomaly maps you often see it a bit lower in that region, but I didn't realize the "hole" was so strongly apparent in the observations.