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Title: Lagrangian Perspective on the Origins of Denmark Strait Overflow
Abstract The Denmark Strait Overflow (DSO) is an important contributor to the lower limb of the Atlantic meridional overturning circulation (AMOC). Determining DSO formation and its pathways is not only important for local oceanography but also critical to estimating the state and variability of the AMOC. Despite prior attempts to understand the DSO sources, its upstream pathways and circulation remain uncertain due to short-term (3–5 days) variability. This makes it challenging to study the DSO from observations. Given this complexity, this study maps the upstream pathways and along-pathway changes in its water properties, using Lagrangian backtracking of the DSO sources in a realistic numerical ocean simulation. The Lagrangian pathways confirm that several branches contribute to the DSO from the north such as the East Greenland Current (EGC), the separated EGC (sEGC), and the North Icelandic Jet (NIJ). Moreover, the model results reveal additional pathways from south of Iceland, which supplied over 16% of the DSO annually and over 25% of the DSO during winter of 2008, when the NAO index was positive. The southern contribution is about 34% by the end of March. The southern pathways mark a more direct route from the near-surface subpolar North Atlantic to the North Atlantic Deep Water (NADW), and needs to be explored further, with in situ observations.  more » « less
Award ID(s):
1835640 1633124
NSF-PAR ID:
10199293
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Journal of Physical Oceanography
Volume:
50
Issue:
8
ISSN:
0022-3670
Page Range / eLocation ID:
2393 to 2414
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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