Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic

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State: Public
Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_F52CF3B86F31
Type
Article: article from journal or magazin.
Collection
Publications
Title
Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic
Journal
Journal of Geophysical Research: Oceans
Author(s)
Dukhovskoy D. S., Yashayaev I., Proshutinsky A., Bamber J. L., Bashmachnikov I. L., Chassignet E. P., Lee C. M., Tedstone A. J.
ISSN
2169-9275
2169-9291
Publication state
Published
Issued date
05/2019
Peer-reviewed
Oui
Volume
124
Number
5
Pages
3333-3360
Language
english
Abstract
The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km3 since the 1990s. The volume of this surplus freshwater is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveals freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50–100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of freshwater have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
Keywords
Greenland ice sheet melting, freshwater anomaly, subpolar North Atlantic, subpolar gyre, passive tracer numerical experiment, freshwater budget
Pubmed
Web of science
Open Access
Yes
Create date
29/08/2024 10:03
Last modification date
22/11/2024 11:09
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