Faroe Bank Channel Overflow: Mesoscale Variability

• Published in: Journal of Physical Oceanography
• Main Authors: Darelius, E., Fer, I., Quadfasel, D.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2011
• Subjects: Faroe Bank; Greenland
• Online Access: http://hdl.handle.net/11858/00-001M-0000-0018-6AFC-A

The Faroe Bank Channel is the deepest connection through the Greenland-ScotlandRidge, where dense water formed north of the ridge flows southwardover the sill crest, contributing to the formation of North AtlanticDeep Water. The overflow region is characterized by high mesoscalevariability and energetic oscillations, accompanied by a high degreeof sea surface level variability. Here, 2-month-long time seriesof velocity and temperature from 12 moorings deployed in May 2008are analyzed to describe the oscillations and explore their generationand propagation. The observed 2.5-5-day oscillations in velocityand temperature are highly coherent both horizontally and vertically,and they are associated with 100-200-m-thick boluses of cold plumewater flowing along the slope. A positive correlation between temperatureand relative vorticity and the distribution of clockwise/counterclockwiserotation across the slope suggest a train of alternating warm cyclonicand cold anticyclonic eddies, where the maximum plume thickness islocated downslope of the eddy center. The along-slope phase velocityis found to be 25-60 cm s−1, corresponding to a wavelength of 75-180km, while the vertical phase propagation is downward. The oscillationsare present already in the sill region. The observations do not matchpredictions for eddies generated either by vortex stretching or baroclinicinstability but agree broadly with properties of topographic Rossbywaves. [ABSTRACT FROM AUTHOR]