Title | Transport Variability of the Irminger Sea Deep Western Boundary Current From a Mooring Array |
Publication Type | Journal Article |
Year of Publication | 2019 |
Authors | Hopkins, JE, Holliday, NP, Rayner, D, Houpert, L, Le Bras, I, Straneo, F, Wilson, C, Bacon, S |
Journal | Journal of Geophysical Research-Oceans |
Volume | 124 |
Pagination | 3246-3278 |
Type of Article | Journal Article |
Abstract | The Deep Western Boundary Current in the subpolar North Atlantic is the lower limb of the Atlantic Meridional Overturning Circulation and a key component of the global climate system. Here, a mooring array deployed at 60°N in the Irminger Sea, between 2014 and 2016, provides the longest continuous record of total Deep Western Boundary Current volume transport at this latitude. The 1.8-year averaged transport of water denser than σθ = 27.8 kg/m3 was −10.8 ± 4.9 Sv (mean ± 1 std; 1 Sv = 106 m3/s). Of this total, we find −4.1 ± 1.4 Sv within the densest layer (σθ > 27.88 kg/m3) that originated from the Denmark Strait Overflow. The lighter North East Atlantic Deep Water layer (σθ = 27.8–27.88 kg/m3) carries −6.5 ± 7.7 Sv. The variability in transport ranges between 2 and 65 days. There is a distinct shift from high to low frequency with distance from the East Greenland slope. High-frequency fluctuations (2–8 days) close to the continental slope are likely associated with topographic Rossby waves and/or cyclonic eddies. Here, perturbations in layer thickness make a significant (20–60%) contribution to transport variability. In deeper water, toward the center of the Irminger Basin, transport variance at 55 days dominates. Our results suggest that there has been a 1.8 Sv increase in total transport since 2005–2006, but this difference can be accounted for by a range of methodological and data limitation biases |
DOI | 10.1029/2018JC014730 |
Array | Global Irminger |
Bibliometrics |
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