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

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), for...

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Bibliographic Details
Main Authors: Chambers, Don, Dixon, Timothy H., Bonin, Jennifer, van den Broeke, M. R., Yang, Qian, Ribergaard, Mads H., Mortensen, John, Myers, Paul G.
Format: Other/Unknown Material
Language:English
Published: 2016
Subjects:
geo
envir
Arctic
Greenland
Ice Sheet
Labrador Sea
North Atlantic
Online Access:https://doi.org/10.7939/R39C6SF8X
https://era.library.ualberta.ca/items/429bb511-e7a1-4944-baa8-14f08502b0ba
Description
Summary: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.

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