Structure of the Deep Spillway in the Western Part of the Romanche Fracture Zone Full article
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Journal of Geophysical Research: Oceans
ISSN: 2169-9275 |
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| Output data | Year: 2018, Volume: 123, Number: 11, Pages: 8508-8531 Pages count : 21 DOI: 10.1029/2018JC013961 | ||||||
| Tags | Antarctic bottom water; hydraulic control overflow; Romanche fracture zone | ||||||
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Abstract:
Structure of the deep spillway was studied on the basis of conductivity-temperature-depth, lowered acoustic Doppler current profiler, and mooring measurements in 2011–2014 in the Romanche fracture zone (22°270–22°320W). The spillway exists quasi-permanently in the regime of hydraulic control overflow and consists of two flows in the layer θ < 1.20 °C (deeper than 4,150 m). The first flow enters the racture from the south through a gap in the Southern Wall. The second flow is directed to the east along the narrow valley of the fracture. The sill depths of these passages are 4,570 and 4,430m, respectively. The depths over the surrounding ridges are shallower than 4,100 m. Both flows descend to the local depression of the fracture with 5,000-m depth. Bottom potential temperatures over both sills were 0.51 °C, and the measured velocitieswere 20–40 cm/s. When the flowsdescend downthe slope, theyaccelerate in supercritical regime. Maximal measured velocities were up to 65 cm/s. Analysis of the 189-day time series of velocities on the mooring deployed in the flow descending from the gap showed a very high level of fluctuation energy: 10 timesgreaterthantheenergyofthebarotropictideatthispoint.Theonlyenergysourceofthese fluctuations is the available potential energy of the deep thermocline in the West Atlantic transforming to the kinetic energy of the deep spillway. The total transport of the bottom water below θ = 1.2 °C based on the lowered acoustic Doppler current profiler measurements is estimated at 0.29–0.35 Sv, which agrees with the predicted values.
Cite:
Tarakanov R.Y.
, Morozov E.G.
, van Haren H.
, Makarenko N.I.
, Demidova T.A.
Structure of the Deep Spillway in the Western Part of the Romanche Fracture Zone
Journal of Geophysical Research: Oceans. 2018. V.123. N11. P.8508-8531. DOI: 10.1029/2018JC013961 WOS Scopus РИНЦ OpenAlex
Structure of the Deep Spillway in the Western Part of the Romanche Fracture Zone
Journal of Geophysical Research: Oceans. 2018. V.123. N11. P.8508-8531. DOI: 10.1029/2018JC013961 WOS Scopus РИНЦ OpenAlex
Dates:
| Submitted: | Mar 6, 2018 |
| Accepted: | Oct 5, 2018 |
Identifiers:
| Web of science: | WOS:000453907000045 |
| Scopus: | 2-s2.0-85057450573 |
| Elibrary: | 41859806 |
| OpenAlex: | W2897614154 |