Wind‐Driven Downwelling Along the West Greenland Shelf and Slope From 6 Years of Mooring Data

Abstract The West Greenland boundary current system plays a central role in modulating deep convection in the Labrador Sea. Here, we use 6 years of mooring data, 2014–2020, together with atmospheric and oceanic reanalysis fields, to investigate wind‐driven downwelling along the southwest Greenland shelf/slope. A total of 49 downwelling events were identified using timeseries of alongcoast wind and bottom density anomaly. On average, the events last 4.5 days and are characterized by increased southeasterly winds followed by an increase in alongstream velocity by ∼0.12 m/s and decrease in bottom density by ∼0.18 kg/m 3 . A cross‐stream Ekman cell develops, although the response is weaker offshore. The events are driven by low‐pressure systems originating from the southwest/south that progress into the Labrador Sea and generate strong southeasterly winds along southwest Greenland. More downwelling events occur in summer, but the ocean response is weaker due to less intense winds during this season. The largest number of events occurred in 2017–2018, coinciding with the period when the deepest convection occurred in the interior Labrador Sea over the past 30 years. The ocean reanalysis fields reveal significant positive anomalies of upper‐layer salinity and density in the interior Labrador Sea during the fall to early winter of 2017–2018. These anomalies likely reflect reduced seaward spreading of freshwater from the shelf due to the more frequent downwelling winds. Our results highlight the important role of wind‐driven downwelling along the west Greenland coast in preconditioning Labrador Sea deep convection, thereby influencing the large‐scale ocean circulation and climate system.