Publication Date:
2020-07-07
Description:
We quantify Atlantic Water heat loss north of Svalbard using year-long hydrographic and
current records from three moorings deployed across the Svalbard Branch of the Atlantic Water boundary
current in 2012–2013. The boundary current loses annually on average 16W m−2 during the eastward
propagation along the upper continental slope. The largest vertical fluxes of 〉100W m−2 occur episodically
in autumn and early winter. Episodes of sea ice imported from the north in November 2012 and February
2013 coincided with large ocean-to-ice heat fluxes, which effectively melted the ice and sustained open
water conditions in the middle of the Arctic winter. Between March and early July 2013, a persistent ice
cover-modulated air-sea fluxes. Melting sea ice at the start of the winter initiates a cold, up to 100-m-deep
halocline separating the ice cover from the warm Atlantic Water. Semidiurnal tides dominate the energy
over the upper part of the slope. The vertical tidal structure depends on stratification and varies seasonally,
with the potential to contribute to vertical fluxes with shear-driven mixing. Further processes impacting the
heat budget include lateral heat loss due to mesoscale eddies, and modest and negligible contributions of
Ekman pumping and shelf break upwelling, respectively. The continental slope north of Svalbard is a key
example regarding the role of ocean heat for the sea ice cover. Our study underlines the complexity of the
ocean’s heat budget that is sensitive to the balance between oceanic heat advection, vertical fluxes, air-sea
interaction, and the sea ice cover.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
peerRev
Format:
application/pdf
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