Seasonal variability in the along-fjord flow in a Northeast Greenland fjord

Understanding along-fjord flow and fjord-shelf exchange around Greenland is key to comprehend inland-freshwater export to Greenland Sea and shelf-water import into fjords. In Northeast Greenland processes driving fjord-shelf exchange remain poorly understood even though these processes are crucial for nutrient supply, and heat transport, among others. Here, we combined records of wind from meteorological towers and water currents from a moored ADCP to assess seasonal along-fjord flow and consequent fjord-shelf exchange in Young Sound Fjord. Results show seasonality in the direction of the wind. Northerly winds predominated in September-April and southeasterlies in June-July. May and August were transitional periods. In ice-free periods, variability in along-fjord transport mirrored wind direction and intensity. In-fjord winds drove in-fjord flow and winds in the opposite direction enhanced on-shelf transport. Most of the exports occurred in the top 10 m where velocities were an order of magnitude greater than below. Bottom in-fjord transport was partially attributed to a wind-driven compensatory flow. During ice-covered conditions, intense winds generated a coastal polynya coupling winds with currents in the water column. For the whole record on-shelf transport was on average an order of magnitude greater than in-fjord import of shelf water. δ18O shows Polar Water was imported in the lower part of the water column while inland freshwater was exported in the upper 10-15 m. This study highlights that, to comprehend freshening of Greenland Sea, winds in fjords and associated transport must be considered.