Episodic Southern Ocean heat loss and its mixed layer impacts revealed by the farthest south multiyear surface flux mooring

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 5002-5010, doi:10.1029/2017GL076909. The Ocean Observa...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Ogle, Sarah E., Tamsitt, Veronica, Josey, Simon A., Gille, Sarah T., Ceroveˇcki, Ivana, Talley, Lynne D., Weller, Robert A.
Format: Article in Journal/Newspaper
Language:English
Published: John Wiley & Sons 2018
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Online Access:https://hdl.handle.net/1912/10444
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Summary:Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 5002-5010, doi:10.1029/2017GL076909. The Ocean Observatories Initiative air‐sea flux mooring deployed at 54.08°S, 89.67°W, in the southeast Pacific sector of the Southern Ocean, is the farthest south long‐term open ocean flux mooring ever deployed. Mooring observations (February 2015 to August 2017) provide the first in situ quantification of annual net air‐sea heat exchange from one of the prime Subantarctic Mode Water formation regions. Episodic turbulent heat loss events (reaching a daily mean net flux of −294 W/m2) generally occur when northeastward winds bring relatively cold, dry air to the mooring location, leading to large air‐sea temperature and humidity differences. Wintertime heat loss events promote deep mixed layer formation that lead to Subantarctic Mode Water formation. However, these processes have strong interannual variability; a higher frequency of 2 σ and 3 σ turbulent heat loss events in winter 2015 led to deep mixed layers (>300 m), which were nonexistent in winter 2016. NSF Grant Number: PLR-1425989; NSF Grant Number: OCE-1357072; NSF Grant Number: OCE-1658001; UK Natural Environment Research Council; ORCHESTRA Grant Number: NE/N018095/1 2018-11-11