Abstract:
Recent geological studies have revealed that the freshwater input to the Arctic Ocean was highly variable during the Holocene. In the present study, the in uence of mid-Holocene river runoff on large-scale Arctic ocean/sea-ice dynamics is examined using a general circulation model. A palaeohydrological forcing for the time interval around 6 ka BP (14 C timescale) is constructed by compiling data from the available literature. Keeping all other forcing elds and bottom topography of the ocean model at present-day values, the effect of a changed freshwater input to the Arctic Ocean is isolated. The model shows that freshwater supply is vitally important for the polar oceanic circulation. In particular, a close connection between Siberian river runoff and the path of the Transpolar Drift (TPD) is found. Consistent with palaeoceanographic ndings of driftwood delivery to the Canadian Arctic Archipelago and Baff n Bay, the model results suggest that enhanced freshwater discharge during the mid-Holocene caused an eastward shift of the TPD with strengthened out ow through Fram Strait.
