Antarctic Bottom Water in the Vema Fracture Zone

Antarctic Bottom Water in the Vema Fracture Zone Full article

Journal

Journal of Geophysical Research: Oceans
ISSN: 2169-9275

Output data

Year: 2023, Volume: 128, Number: 8, Article number : e2023JC019967, Pages count : 13 DOI: 10.1029/2023jc019967

Tags

VEMA FRACTURE ZONE, ANTARCTIC BOTTOM WATER, UNDERWATER SPILLWAY, LOW VELOCITY ZONE

Authors

Morozov E.G. ^1,2 , Frey D.I. ^1,2,3 , Zuev O.A. ¹ , Makarenko N.I. ⁴ , Seliverstova A.M. ¹ , Mekhova O.S. ^1,5 , Krechik V.А. ¹

Affiliations

1	Moscow Institute of Physics and Technology, Dolgoprudny, Russia
2	Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia
3	Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russia
4	Lavrentiev Institute of Hydrodynamics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
5	St. Petersburg State University, St. Petersburg, Russia

A section of 46 CTD/Lowered Acoustic Doppler Current Profiler stations along the Vema Fracture Zone (VFZ) was made for the first time with a repeat of the transverse section on the main sill (at 41° W) for the sixth time. Potential temperature of Antarctic Bottom Water when it flows into the fracture increases from 1.3°С to 1.6°C. This temperature increase is much smaller than in the Romanche Fracture Zone because in the VFZ there are not many transverse sills that force the flow to become turbulent. A zone with minimal velocities of the bottom flows exists in the western part of the VFZ up to the main sill. A current with velocities of 0.25 m/s flows above the low velocity zone at a depth of about 4,000 m. Underwater spillways with hydraulically controlled flow of bottom water down the slope from 4,500 m to 5,000 m at speeds up to 0.40 m/s were found east of the sill (in the central and southern channels). The bottom current accelerates as it flows down, but then its kinetic energy decreases. The bottom current slows down and mixes with surrounding waters. A thin (∼30 m). bottom flow descends further to the deep depression. In the southern channel of the VFZ, bottom water flows into a deep (5,400 m) basin. The coldest and densest water reaches this depression during rare inflows.

Morozov E.G. , Frey D.I. , Zuev O.A. , Makarenko N.I. , Seliverstova A.M. , Mekhova O.S. , Krechik V.А.
Antarctic Bottom Water in the Vema Fracture Zone
Journal of Geophysical Research: Oceans. 2023. V.128. N8. e2023JC019967 :1-13. DOI: 10.1029/2023jc019967 WOS Scopus РИНЦ OpenAlex

Web of science:	WOS:001047634600001
Scopus:	2-s2.0-85167930744
Elibrary:	60240752
OpenAlex:	W4385632486

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