Multidecadal changes in Iceland Scotland Overflow Water vigor over the last 600 years and its relationship to climate

Abstract

Changes in the Atlantic Meridional Overturning Circulation (AMOC) have commonly been invoked to explain the low-frequency climate changes evident over millennial-multidecadal timescales during the Holocene period. While there is growing evidence that deep ocean circulation varied on millennial timescales, little is known about ocean variability on shorter timescales. Here we use a marine sediment core (GS06-144-09MC-D) recovered from a high accumulation rate site on the Gardar Drift in the Iceland Basin (60°19′N, 23°58′W, 2081 m) to reconstruct decadal-centennial variability in the vigor of Iceland-Scotland Overflow Water (ISOW) with the paleocurrent proxy “sortable silt” mean grain size math formula. Our math formula record reveals that changes in ISOW vigor have occurred on multidecadal-centennial timescales over the past ~600 years; similar timescales as documented in Atlantic Multidecadal Variability observations and reconstructions. Our findings support a link between changes in basin-wide climate and deep ocean circulation.