Journal Article

Snow Loss Into Leads in Arctic Sea Ice: Minimal in Typical Wintertime Conditions, but High During a Warm and Windy Snowfall Event

Polashenski, Chris, Granskog, Mats A., Schneebeli, Martin, Macfarlane, Amy R., Clemens‐Sewall, David, Frey, Markus M., Fons, Steven W., Hutchings, Jennifer K., Cox, Christopher J., Albedyll, Luisa, Arndt, Stefanie, Perovich, Don, Schmale, Julia

2023

Overview

The amount of snow on Arctic sea ice impacts the ice mass budget. Wind redistribution of snow into open water in leads is hypothesized to cause significant wintertime snow loss. However, there are no direct measurements of snow loss into Arctic leads. We measured the snow lost in four leads in the Central Arctic in winter 2020. We find, contrary to expectations, that under typical winter conditions, minimal snow was lost into leads. However, during a cyclone that delivered warm air temperatures, high winds, and snowfall, 35.0 ± 1.1 cm snow water equivalent (SWE) was lost into a lead (per unit lead area). This corresponded to a removal of 0.7–1.1 cm SWE from the entire surface—∼6%–10% of this site's annual snow precipitation. Warm air temperatures, which increase the length of time that wintertime leads remain unfrozen, may be an underappreciated factor in snow loss into leads. Plain Language Summary The amount of snow on Arctic sea ice impacts how quickly the ice grows in the winter and melts in the summer. Cracks in the ice, known as leads, expose ocean water that snow can be blown into, reducing the amount of snow on the ice and thus impacting ice growth and melt. We found that in typical wintertime conditions, very little snow is blown into leads. However, if there is fresh snowfall, it is uncommonly warm and it is very windy at the same time when leads are forming, a large amount of snow can be blown into the ocean. Accounting for the impacts of air temperature on this process will enable scientists to better understand how much snow is on Arctic sea ice, and hence how quickly the ice grows in the winter and melts in the summer, and how this might change in a future, warmer, Arctic. Key Points Minimal snow was lost into leads in observations of three cases in typical wintertime, cold, moderately windy conditions on Arctic sea ice In an atmospheric advection event with air temperature above −10°C, high wind, and fresh snowfall, most recent snowfall was lost into leads Warm air temperatures increase the duration of unfrozen water in leads, which may be an underappreciated factor in snow loss into leads

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Air temperature / Annual precipitation / Arctic sea ice / Ice / Mass budget / Melts / Oceans / Sea ice / Seawater / Snow / snow loss into leads / Snow-water equivalent / Snowfall / Summer / Warm air / Winds / Winter