Extremely long Kelvin-Helmholtz billow trains in the Romanche Fracture Zone
International audience In the Atlantic Ocean, the densest water mass Antarctic Bottom Water " AABW " can only cross the Mid-Atlantic Ridge from its southwestern to northeastern basins in limited, because deep, conduits. At the southwestern entrance of one of these, the equatorial Romanche...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , |
Other Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2014
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-01166123 https://hal.archives-ouvertes.fr/hal-01166123/document https://hal.archives-ouvertes.fr/hal-01166123/file/VANHAREN__GRL_2014.pdf https://doi.org/10.1002/2014GL062421 |
Summary: | International audience In the Atlantic Ocean, the densest water mass Antarctic Bottom Water " AABW " can only cross the Mid-Atlantic Ridge from its southwestern to northeastern basins in limited, because deep, conduits. At the southwestern entrance of one of these, the equatorial Romanche Fracture Zone, AABW crosses a sill at 4550 m depth in a 7 km narrow channel before plunging into the deep. At the sill-slope, the rapidly flowing AABW causes shear-induced turbulent mixing with the overlying water masses. We present an excerpt of 1 Hz sampled, half-yearlong moored observations from 99 high-resolution temperature sensors that demonstrate and quantify the turbulence details. On top of quasi-steady shear flow, an internal tide modulates the mixing. Together, they constitute a means for an extremely long train of >250 consecutive Kelvin-Helmholtz billows in a day that vary between 5 and 100 m in vertical scale. |
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