Transports and pathways of overflow water in the Rockall Trough

Water mass analysis reveals a persistent core of deep overflow water within the Rockall Trough which hugs the northern and western boundaries of the basin. Mean speeds within this overflow are 10-15 cm s-1 giving a transport time from the Wyville Thomson Ridge to the central basin of < 50 days. A...

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Bibliographic Details
Published in:Deep Sea Research Part I: Oceanographic Research Papers
Main Authors: Johnson, Clare, Sherwin, Toby, Cunningham, Stuart, Dumont, Estelle, Houpert, Loic, Holliday, N. Penny
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Online Access:https://pure.uhi.ac.uk/en/publications/e3f36f0e-84bc-4244-af2b-40245a5c504c
https://doi.org/10.1016/j.dsr.2017.02.004
https://pureadmin.uhi.ac.uk/ws/files/2067758/paper_as_accepted.pdf
http://authors.elsevier.com/sd/article/S0967063716302503
Description
Summary:Water mass analysis reveals a persistent core of deep overflow water within the Rockall Trough which hugs the northern and western boundaries of the basin. Mean speeds within this overflow are 10-15 cm s-1 giving a transport time from the Wyville Thomson Ridge to the central basin of < 50 days. Analysis of the 40-year Extended Ellett Line record shows proportions of Norwegian Sea Deep Water associated with the deep core exceed 15 % around one quarter of the time. We present the first transport estimates for overflow water in the Rockall Trough. This flux is for overflow water modified by mixing with a density greater than 27.65 kg m-3. Mean values calculated both from a newly deployed mooring array (OSNAP project) and indirectly from the Extended Ellett Line time-series are -0.3 ± 0.04 Sv. Although the flux is highly variable there is no long term trend. As some overflow appears to exit into the Iceland Basin via channels between the northern banks, we suggest that the volume transport will likely increase as the flow pathway is traced back around the boundary of the Rockall Trough towards the Wyville Thomson Ridge.