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Drivers of surface salinity changes in the Greenland-Iceland Seas on seasonal and interannual time scales - a climate model study
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  • Helene Reinertsen Langehaug,
  • Ailin Brakstad,
  • Kjetil Våge,
  • Emil Jeansson,
  • Mehmet Ilicak,
  • Caroline A. Katsman
Helene Reinertsen Langehaug
Nansen Environmental and Remote Sensing Center

Corresponding Author:[email protected]

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Ailin Brakstad
University of Bergen
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Kjetil Våge
University of Bergen
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Emil Jeansson
NORCE Norwegian Research Centre, Bjerknes
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Mehmet Ilicak
Istanbul Technical University
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Caroline A. Katsman
Delft University of Technology
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Abstract

The Arctic climate is changing dramatically, especially in terms of sea ice loss, with potentially large downstream impacts on the Nordic Seas and the North Atlantic Ocean. The East Greenland Current (EGC) transports substantial amounts of freshwater (in liquid and solid states) southward along the east Greenland continental slope. To increase our understanding of the drivers of surface salinity changes in the interior Nordic Seas, we investigate the diversion of freshwater from the EGC into the Nordic Seas. To this end, we analyse the outcomes of an ocean model hindcast for the period 1973-2004 with a horizontal resolution of 0.25 degree. We find that sea ice contributes large amounts of freshwater to the interior Nordic Seas. On an interannual time scale, this sea ice diversion has a high and significant correlation with surface salinity in the Greenland and Iceland Seas (correlation < -0.7). On a seasonal time scale, the model hindcast and observations demonstrate a clear signal in surface salinity: a lateral migration of the Polar Front position occurring along all of east Greenland. In the model hindcast, these lateral shifts in the front are consistent with seasonal changes in the westward wind-driven Ekman transport. Thus, this climate model study indicates that there are two main causes of seasonal and interannual surface salinity changes; wind-driven Ekman transport and sea ice diversion from the EGC, respectively.