East Atlantic Pattern Drives Multidecadal Atlantic Meridional Overturning Circulation Variability during the Last Glacial Maximum, link to netCDF files

The variability of the Atlantic Meridional Overturning Circulation (AMOC) and its governing processes during the Last Glacial Maximum (LGM) is investigated in the Kiel Climate Model (KCM). Under LGM conditions, enhanced multidecadal AMOC variability is simulated relative to a preindustrial control run and surface heat flux variability linked to the East Atlantic pattern the primary driver of AMOC variability. In contrast, the multidecadal AMOC variability in the preindustrial control simulation is mainly driven by surface heat flux variability associated with the North Atlantic Oscillation (NAO). Stand-alone atmosphere model experiments show that the difference in mechanism is tightly linked to the differences in topography. The stronger multidecadal AMOC variability suggested by the KCM may be an important additional factor to understanding abrupt climate changes over the North Atlantic sector during the LGM.