title: Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation.
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.
authors.affiliation: School of Geosciences, University of South Florida, 4202 E Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: School of Geosciences, University of South Florida, 4202 E Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Dixon
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 ESB, Edmonton, Alta, Canada T6G 2E3.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Myers
authors.affiliation: College of Marine Science, University of South Florida, St. Petersburg, Florida 33701, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bonin
authors.affiliation: College of Marine Science, University of South Florida, St. Petersburg, Florida 33701, USA.
authors.forename: Don
authors.initials: D
authors.lastname: Chambers
authors.affiliation: Institute for Marine and Atmospheric Research Utrecht, Utrecht University, P.O. Box 80.005, 3508 TA, Utrecht, The Netherlands.
authors.forename: M R
authors.initials: MR
authors.lastname: van den Broeke
authors.forename: Mads H
authors.initials: MH
authors.lastname: Ribergaard
authors.forename: John
authors.initials: J
authors.lastname: Mortensen