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- Title
Temporal Variability of the Labrador Current Pathways Around the Tail of the Grand Banks at Intermediate Depths in a High‐Resolution Ocean Circulation Model.
- Authors
Gonçalves Neto, Afonso; Palter, Jaime B.; Xu, Xiaobiao; Fratantoni, Paula
- Abstract
The Northwest Atlantic Shelf and Slope have warmed dramatically in the past decade, changing marine life and challenging fisheries management. A rapid warming event in 2009/2010, linked to a reduced supply of cold water from the Labrador Sea, pushed this region to a new state of unprecedentedly high temperatures that persists today. However, a mechanistic understanding of how the Labrador Current connectivity is reduced at the Tail of the Grand Banks of Newfoundland has been lacking. Here, we present the results of a 25‐year (1993–2017) Lagrangian analysis using the HYbrid Coordinate Ocean Model. Synthetic particles were released in the vicinity of the Labrador Current upstream of the Grand Banks and tracked in a 2‐D velocity field. We found that the Labrador Current can be completely blocked by Gulf Stream eddies and meanders that impinge on the shelf break along the Grand Banks. This blocking can occur in many different locations at, upstream, or downstream of the Tail of the Grand Banks, since the Labrador Current needs a clear passage over a long distance to continue its path. In the simulation, the Labrador Current has been blocked more often since 2008, which led to the warming of the Northwest Atlantic Shelf and Slope. These results, which are consistent with satellite observations, can provide predictability for the New England and Nova Scotia shelf environments potentially helpful for ecosystem management. Plain Language Summary: The New England and Nova Scotia continental shelves have been warming at a rate much faster than almost anywhere else in the global ocean. Just east of this region, two of the Atlantic's mightiest currents—the warm Gulf Stream and the cold Labrador Current—interact near the edge of an underwater plateau called the Grand Banks of Newfoundland. Previous observational work suggested that the warming of the continental shelf has been caused by the rising proportion of Gulf Stream waters, due to the reduced contribution of Labrador Current as it rounds the Grand Banks. Here, we use an ocean model that simulates circulation in this region with excellent accuracy to take a deeper look at the drivers of this blockage of the Labrador Current. The model suggests that when the swirling Gulf Stream eddies approach the Grand Banks, they prevent the Labrador Current from continuing its journey to the west, ultimately starving the New England and Nova Scotia continental shelves of a source of cold, fresh water. Because the Gulf Stream eddies have a clear sea surface height signature, an indication of these blocking dynamics may be observed by satellite. Key Points: Virtual Lagrangian particles were launched in the Labrador Current upstream of the Tail of the Grand Banks, using an eddy‐resolving modelThe presence of Gulf Stream eddies at the Tail of the Grand Banks strongly modulates westward transport in the Labrador CurrentInterannual variability in the impingement of Gulf Stream eddies has prevented westward penetration of the Labrador Current in recent years
- Subjects
GRAND Banks of Newfoundland; NOVA Scotia; NEW England; CIRCULATION models; GULF Stream; LAGRANGIAN points; OCEAN circulation; ECOSYSTEM management; CONTINENTAL shelf; MEANDERING rivers
- Publication
Journal of Geophysical Research. Oceans, 2023, Vol 128, Issue 3, p1
- ISSN
2169-9275
- Publication type
Article
- DOI
10.1029/2022JC018756