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Episodic Reversal of Autumn Ice Advance Caused by Release of Ocean Heat in the Beaufort Sea
Author(s) -
Smith Madison,
Stammerjohn Sharon,
Persson Ola,
Rainville Luc,
Liu Guoqiang,
Perrie William,
Robertson Robin,
Jackson Jennifer,
Thomson Jim
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2018jc013764
Subject(s) - drift ice , sea ice , arctic ice pack , sea ice thickness , antarctic sea ice , geology , climatology , oceanography , heat flux , arctic sea ice decline , cryosphere , environmental science , heat transfer , physics , thermodynamics
High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on‐ice winds over a vast fetch caused mixing and release of heat from the upper ocean. This heat was sufficient to melt large areas of thin, newly formed pancake ice; an average of 10 MJ/m 2 was lost from the upper ocean in the study area, resulting in ∼3–5 cm pancake sea ice melt. Heat and salt budgets create a consistent picture of the evolving air‐ice‐ocean system during this event, in both a fixed and ice‐following (Lagrangian) reference frame. The heat lost from the upper ocean is large compared with prior observations of ocean heat flux under thick, multiyear Arctic sea ice. In contrast to prior studies, where almost all heat lost goes into ice melt, a significant portion of the ocean heat released in this event goes directly to the atmosphere, while the remainder (∼30–40%) goes into melting sea ice. The magnitude of ocean mixing during this event may have been enhanced by large surface waves, reaching nearly 5 m at the peak, which are becoming increasingly common in the autumn Arctic Ocean. The wave effects are explored by comparing the air‐ice‐ocean evolution observed at short and long fetches, and a common scaling for Langmuir turbulence. After the event, the ocean mixed layer was deeper and cooler, and autumn ice formation resumed.