Wind-driven Arctic freshwater anomalies

Large freshwater (FW) anomalies have been observed in the Arctic FW budget and exports in the last decade but their origin is unclear. This letter examines if the large-scale wind conditions might be responsible. We employ an idealized model forced by wind conditions that generate FW budget anomalies. Anticyclonic (cyclonic) winds cause an increase (decrease) of FW in the Western Arctic. For anticyclonic winds, the magnitude and timescale of the FW accumulation in the Western Arctic are similar to observations. Importantly, a cyclonic shift in the winds can only generate a realistically large release event if the Western Arctic is anomalously fresh beforehand. Given that the Western Arctic presently stores excess FW, the findings suggest that a present-day shift to cyclonic winds will generate a large release of liquid FW from the Arctic through the Canadian Arctic Archipelago. Key Points Wind conditions can generate significant Arctic freshwater anomalies Response to a change of wind regime depends on the Arctic freshwater inventory Cyclonic shift of present winds will release Arctic freshwater west of Greenland