Deep ventilation in the Okinawa Trough induced by Kerama Gap overflow SCIE SCOPUS

Cited 18 time in WEB OF SCIENCE Cited 23 time in Scopus
Title
Deep ventilation in the Okinawa Trough induced by Kerama Gap overflow
Author(s)
Nishina, Ayako; Nakamura, Hirohiko; Park, Jae-Hun; Hasegawa, Daisuke; Tanaka, Yuki; Seo, Seongbong; Hibiya, Toshiyuki
Alternative Author(s)
서성봉
Publication Year
2016-08
Abstract
Near-bottom water flowing over the Kerama Gap's sills is thought to ventilate the deep water below similar to 1100 m depth in the Okinawa Trough and then upwell with 5-10 years residence time. The present study follows up on this phenomenon, using comprehensive profile data of temperature, salinity, dissolved oxygen, currents and turbulence obtained by intensive shipboard observations performed in June 2013 and June 2014 in the region. Strong near-bottom subtidal flow with speeds exceeding 0.5 m s(-1) was observed within a layer of about 100 m thickness over the western side of the peak of the main sill. Temperature and salinity sections along the Kerama Gap indicated some depressions and overturns of the deep water downstream of the strong overflow, suggesting the existence of breaking internal gravity waves and hydraulic jumps. Associated vertical diffusivities, estimated using the Thorpe scale and the buoyancy frequency, were three to four orders of magnitude larger than typical values observed in the thermocline of the open ocean (similar to 10(-5) m(2) s(-1)). The dissolved oxygen section also indicated strong vertical mixing and associated upwelling with the entrainment of the near-bottom overflow water into the lower thermocline beneath the Kuroshio in the Okinawa Trough. The present study not only supports the previous conceptual model but also provides new evidence that the Okinawa Trough is an upwelling location where nutrient rich Philippine Sea intermediate water is sucked up into the lower thermocline below the Kuroshio.
ISSN
2169-9275
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/2159
DOI
10.1002/2016JC011822
Bibliographic Citation
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, v.121, no.8, pp.6092 - 6102, 2016
Publisher
AMER GEOPHYSICAL UNION
Subject
NORTHEASTWARD CURRENT SOUTHEAST; RYUKYU ISLANDS; VARIABILITY
Keywords
deep ventilation; Kerama Gap; meridional overturning circulation; near-bottom overflow; North Pacific Intermediate Water; vertical mixing
Type
Article
Language
English
Document Type
Article
Files in This Item:
There are no files associated with this item.

qrcode

Items in ScienceWatch@KIOST are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse