A modern prototype three-layer stratification in the Arctic Ocean since the Miocene


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akil.hossain [ at ] awi.de

Abstract

The tectonic opening of the Fram Strait (FS) was critical to the water exchange between the Atlantic Ocean and the Arctic Ocean, and caused the transition from a restricted to a ventilated Arctic Ocean during early Miocene. If and how the water exchange between the Arctic Ocean and the North Atlantic influenced the global current system is still disputed. We apply a fully coupled atmosphere-ocean-sea-ice model to investigate stratification and ocean circulation in the Arctic Ocean in response to the opening of the FS during early to middle Miocene. Progressive widening of the FS gateway in our simulation causes a moderate warming, while salinity conditions in the Nordic Seas remain similar. On the contrary, with increasing FS width Arctic temperatures remain unchanged and salinity changes appear to steadily become stronger. For a sill depth of ~1500 m, we achieve ventilation of the Arctic Ocean due to enhanced import of saline Atlantic water through a FS width of ~105 km. Moreover, at this width and depth, we detect a modern-like three-layer stratification in the Arctic Ocean. The exchange flow through FS is characterized by vertical separation of a low salinity cold outflow from the Arctic Ocean confined to a thin upper layer, an intermediate saline inflow from the Atlantic Ocean below and a cold bottom Arctic outflow. Using a significantly shallower and narrower FS during the early Miocene, our study suggests that the ventilation mechanisms and stratification in the Arctic Ocean are comparable to the present-day characteristics.



Item Type
Conference (Poster)
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Helmholtz Cross Cutting Activity (2021-2027)
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Not peer-reviewed
Publication Status
Published
Event Details
EGU General Assembly 2021, 19 Apr 2021 - 30 Apr 2021.
Eprint ID
55659
DOI 10.5194/egusphere-egu21-9956

Cite as
Hossain, A. , Knorr, G. , Jokat, W. and Lohmann, G. (2021): A modern prototype three-layer stratification in the Arctic Ocean since the Miocene , EGU General Assembly 2021, 19 April 2021 - 30 April 2021 . doi: 10.5194/egusphere-egu21-9956


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