Arctic Ocean tidal regime change across the Bolling-Allerod onset

<p>Although currently microtidal, the Arctic Ocean is known to have been megatidal at Last Glacial Maximum (LGM) due to the Arctic Ocean basin being nearly entirely enclosed, with only Fram Strait connecting it to the global ocean. This allowed for the propagation of a gravest mode coastal Kelvin wave traveling anti-clockwise around the Arctic ocean. The transition from the megatidal regime at LGM to the mircotidal regime observed today is not well understood, and the factors which control the amplitude of the semidiurnal tidal constituents in the Arctic Ocean have not been fully determined in the literature. We investigate the Arctic tidal regime across the Bolling-Allerod (B-A) onset, 14.6-14.1 ka, finding that the Arctic Ocean is megatidal prior to B-A onset and weakens considerably thereafter. The period of time during which the Arctic tidal regime is enhanced is precisely the time at which high Arctic ice streams begin to deglaciate, indicating that the tides may play a causal role in forcing the rapid deglaciation of the sector of the Laurentide abutting the Arctic Ocean. We further show that the deglaciation of the Laurentide ice sheet, through the mechanisms of Glacial Isostatic Adjustment (GIA) and gravitationally self-consistent local reduction in sea level, causes an increase in the amplitude of the principal lunar and solar semidiurnal tidal constituents in the Arctic Ocean. Additionally, it is the collapse of the Barents sea ice sheet which significantly weakens the Arctic Ocean tidal regime. We report the contribution of each major terrestrial ice sheet to the relative sea-level rise at each of Barbados, Tahiti, and Sunda Shelf, finding that the gravitationally self-consistent GIA model employed accurately predicts the RSL change at each of these sites and determines that the contribution at Barbados from the Laurentide is smaller than the contribution at Tahiti or Sunda Shelf due to the flow of ocean water away from the deglaciating Laurentide and into the "far field."  We further show that the contribution to RSL at Barbados due to the collapse of the Barents Sea ice sheet is significant. </p>