Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation

• Published in: Nature Communications
• Main Authors: Yang, Qian, Dixon, Timothy H., Myers, Paul G., Bonin, Jennifer, Chambers, Don, van den Broeke, M. R., Ribergaard, Mads H., Mortensen, John
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2016
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; Arctic; Greenland; Ice Sheet; Labrador Sea; North Atlantic
• Online Access: http://dx.doi.org/10.1038/ncomms10525; http://www.nature.com/articles/ncomms10525.pdf; http://www.nature.com/articles/ncomms10525

Abstract The Atlantic Meridional Overturning Circulation (AMOC) is an important component of ocean thermohaline circulation. Melting of Greenland’s ice sheet is freshening the North Atlantic; however, whether the augmented freshwater flux is disrupting the AMOC is unclear. Dense Labrador Sea Water (LSW), formed by winter cooling of saline North Atlantic water and subsequent convection, is a key component of the deep southward return flow of the AMOC. Although LSW formation recently decreased, it also reached historically high values in the mid-1990s, making the connection to the freshwater flux unclear. Here we derive a new estimate of the recent freshwater flux from Greenland using updated GRACE satellite data, present new flux estimates for heat and salt from the North Atlantic into the Labrador Sea and explain recent variations in LSW formation. We suggest that changes in LSW can be directly linked to recent freshening, and suggest a possible link to AMOC weakening.