Quantifying Atlantic Water Transport to the Nordic Seas by Combined Use of Gravimetry and Altimetry

R. Raj, J. Nilsen, J. Johannessen, T. Furevik, O. Andersen, L. Bertino

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Abstract

In this study the variability of Atlantic Water (AW) entering the Nordic Seas from the North Atlantic through the passage between Iceland, the Faroe Islands and Scotland has been investigated. The poleward transport of this warm AW is a key component in maintaining a relatively mild climate in the northwestern Europe. Satellite remote sensing datasets from altimetry and the Gravity field and steady state Ocean Circulation Explorer (GOCE) mission, in combination with surface drifters, fixed current meter, and hydrographic data are used. The high-resolution mean dynamic topography (MDT) is shown to resolve the time-invariant surface currents in the inflow region. In addition to the improved MDT, we take benefit of the
new reprocessed sea level anomaly data in the estimation of absolute dynamic topography. Analysis of the monthly surface velocities from 1993-2016 demonstrates significant influence of the large scale atmospheric forcing associated with the North Atlantic Oscillation (NAO). Furthermore, a significant increase in surface velocities along the slope current, front current
and the Norwegian Coastal Current are found during winter. Finally, combining altimetry with hydrographic data, we demonstrate that the variability in surface velocities of the inflow region is also reflected in the deeper layers, and that altimetry therefore can be used to monitor the variability of the poleward transport of AW in this region.
Original languageEnglish
Publication date2018
Number of pages1
Publication statusPublished - 2018
Event25 years of progress in radar altimetry symposium - , Portugal
Duration: 24 Sep 201829 Sep 2018

Conference

Conference25 years of progress in radar altimetry symposium
CountryPortugal
Period24/09/201829/09/2018

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