Wind‐Driven Coastal Upwelling and Downwelling in the Shelfbreak East Greenland Current. Issue 9 (2nd September 2018) - Håvik, Lisbeth
Abstract: The East Greenland Current is a major pathway for freshwater export from the Arctic Ocean and for the transport of dense overflow waters toward the North Atlantic. We use moored measurements from the East Greenland Current north of Denmark Strait from October 2011 to April 2012 to analyze the wind‐driven variability of the shelfbreak branch of this current system. By combining the moored data with atmospheric reanalysis data we found that coastal upwelling and downwelling take place in the shelfbreak East Greenland Current throughout winter. In total, upwelling and downwelling events occur around five times per month, and these events modulate the volume transport and redistribute water masses. Specifically, we find that upwelling may lead to a deposition of dense water masses on the shelf and to an offshore transport of freshwater, while downwelling events are associated with a considerable increase in along‐stream freshwater transport. Based on wind patterns and wind‐driven ocean variability along the east Greenland coast, the integrated effect of these episodes is expected to be substantial. Plain Language Summary: The East Greenland Current contributes to the large‐scale ocean circulation in the North Atlantic. This current transports both freshwater and sea ice southward from the Arctic Ocean and supplies water masses to the deep circulation in the Atlantic Ocean. We use measurements from the East Greenland Current between Iceland and Greenland from October 2011 to April 2012 to analyze the wind‐driven variability in one branch of this current system. By combining the oceanographic data with atmospheric data we found that the wind induced vertical motions in the shelfbreak East Greenland Current throughout winter. In total, these wind‐driven events occur around five times per month and lead to a considerable modulation of the volume transport and a redistribution of water masses both vertically and horizontally. The integrated effect of such episodes is expected to be substantial due to the large region influenced by the wind conditions favorable for this type of oceanic response. Key Points: Mooring data from winter 2011–2012 show that upwelling and downwelling take place in the shelfbreak East Greenland Current Upwelling events may lead to a deposition of dense water masses on the shelf Downwelling events are associated with a considerable increase in freshwater transport