Abstract
AbstractGlobally, the Celtic Sea shelf break is ranked highest as an energetic “hot spot” of tidal energy conversion, therefore making it the most significant contributor to global internal tidal energy flux. In this paper, the three‐dimensional dynamics of baroclinic tides in the shelf‐slope area of the Celtic Sea was investigated numerically and using observational data collected on the 376th cruise of the RV “RRS Discovery” in June 2012. The time series recorded at a shelf break mooring showed that semidiurnal internal waves were accompanied by packets of internal solitary waves with maximum amplitudes up to 105 m, the largest internal waves ever recorded in the Celtic Sea, and ranking among the largest observed in the global ocean. The observed baroclinic wavefields were replicated numerically using the Massachusetts Institute of Technology general circulation model. A fine‐resolution grid with 115 m horizontal and 10 m vertical steps allowed the identification of two classes of short‐scale internal waves. The first classification was generated over headlands and resembles spiral‐type internal waves that are typical for isolated underwater banks. The second classification, generated within an area of several canyons, revealed properties of quasi‐planar internal wave packets. The observed in situ intensification of tidal bottom currents at the shelf break mooring is explained in terms of a tidal beam that was formed over supercritical bottom topography at the mooring location.
Highlights
In situ data on internal tides reported in this paper were collected on the 376th cruise of the RV RRS Discovery in June 2012, in the slope-shelf area of the Celtic Sea (CS) (Figure 1, rectangle)
Internal waves are normally generated by tides over the shelf break [Pingree and Mardell, 1981, 1985; Holt and Thorpe, 1997], where they can dissipate or propagate away from the generation area making a significant contribution to midwater column mixing
In summarizing the main findings of this study on the baroclinic tidal dynamics of the Celtic Sea, one should mention the role that this region plays in global tidal energy conversion
Summary
In situ data on internal tides reported in this paper were collected on the 376th cruise of the RV RRS Discovery (hereafter D376) in June 2012, in the slope-shelf area of the Celtic Sea (CS) (Figure 1, rectangle). Pingree and Mardell [1981] reported on data recorded at two moorings, 001 (48.185N, 7.9W, depth 188 m) and 002 (48.28N, 7.78W, depth 163 m), deployed 13.5 km apart along a line perpendicular to the general shelf edge direction in September 1973. Their data revealed a series of the thermocline depressions at the shallowest of the two moorings (001); 3.2 h later these depressions developed into packets of internal solitary waves recorded at mooring 002.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
