loading page

Observed variability of the North Atlantic Current in the Rockall Trough from four years of mooring measurements.
  • +5
  • Loïc Houpert,
  • Stuart A. Cunningham,
  • Neil J Fraser,
  • Clare Johnson,
  • N. Penny Holliday,
  • Sam C. Jones,
  • Bengamin Ivan Moat,
  • D. Rayner
Loïc Houpert
National Oceanography Centre, National Oceanography Centre

Corresponding Author:[email protected]

Author Profile
Stuart A. Cunningham
Scottish Association For Marine Science, Scottish Association For Marine Science
Author Profile
Neil J Fraser
Scottish Association For Marine Science, Scottish Association For Marine Science
Author Profile
Clare Johnson
Scottish Association For Marine Science, Scottish Association For Marine Science
Author Profile
N. Penny Holliday
National Oceanography Centre, Southampton, National Oceanography Centre, Southampton
Author Profile
Sam C. Jones
Scottish Association For Marine Science, Scottish Association For Marine Science
Author Profile
Bengamin Ivan Moat
National Oceanography Centre, National Oceanography Centre
Author Profile
D. Rayner
National Oceanography Centre, UK, National Oceanography Centre, UK
Author Profile

Abstract

The Rockall Trough is one of the main conduits for warm Atlantic Water to the Nordic Seas. Ocean heat anomalies, originating from the eastern subpolar gyre, are known to influence Arctic sea ice extent, marine ecosystems, and continental climate. Knowledge of the transport through this basin has previously been limited to estimates from hydrographic sections which cannot characterise the intra‑annual and multi‑annual variability. As part of the Overturning in the Subpolar North Atlantic Programme (OSNAP), a mooring array was deployed in the Rockall Trough in order to obtain the first continuous measurements of transport. Results show a 4‑year mean northward transport of 6.6 Sv (1 Sv = 10 m/s) by the North Atlantic Current (NAC) in the east and interior of the Rockall Trough (2014‑2018). A mean transport of ‑2.0 Sv (southward) is observed in the west of the basin, which could be part of a recirculation around the Rockall Plateau. The 90‑day low‑pass filtered transport shows large sub‑annual and inter‑annual variability (‑1.6 Sv to 9.1 Sv), mostly resulting from changes in the mid‑basin geostrophic transport. Satellite altimetry reveals the periods of low and high transport are associated with significant changes in the large-scale NAC circulation. There is a detectable seasonal signal, with the greatest transport in spring and autumn.