Abstract
Sparse observations in the East/Japan Sea (EJS) suggested that open-ocean deep convection occurs south of Vladivostok; however, more recent observations suggest that deep convection occurs along the continental slope, resulting in bottom water formation in the EJS. We investigated the process of deep convection along the EJS continental slope using large-eddy simulation (LES), which demonstrated that dense water, formed by strong wintertime cooling in the shelf, flows down along the slope as a bottom Ekman current. The characteristics of the initial dense water were relatively well conserved on the continental slope during convection, but they changed rapidly by mixing with the surrounding waters in the open ocean. Accordingly, slope convection penetrated deeper compared to open-ocean convection under the same surface heat flux. Our numerical experiments showed that, under typical surface cooling during winter (i.e., 200 W m–2), slope convection reaches depths greater than 2,700 m, generating a potential ventilation process for deep- and bottom-water formations, whereas open-ocean convection reaches approximately 700 m depth, contributing to the intermediate- and central-water formations in the EJS. Various topography experiments revealed that downward speed was proportional to the continental-slope inclination; the initial characteristics remained relatively well conserved at a small continental-slope inclination. Increased salinity due to brine rejection in the shelf could accelerate the slope convection.
Highlights
IntroductionDeep water formation is crucial to the meridional circulation in the East/Japan Sea (EJS) (Han et al, 2020) and the oceans (Alley et al, 2003; Rahmstorf et al, 2015; Bellomo et al, 2021)
The East/Japan Sea (EJS) is a typical semi-enclosed marginal sea, albeit with oceanic characteristics regarding the temperature, salinity, and dissolved oxygen vertical profiles (Gamo and Horibe, 1983; Kim and Kim, 1996; Kim et al, 1996).Deep water formation is crucial to the meridional circulation in the EJS (Han et al, 2020) and the oceans (Alley et al, 2003; Rahmstorf et al, 2015; Bellomo et al, 2021)
It has been suggested that brine rejection plays an important role regarding the ventilation at the continental slope (Talley et al, 2003), our results suggest that the density increase due to cooling without brine rejection allows the bottom water (BW) formation
Summary
Deep water formation is crucial to the meridional circulation in the EJS (Han et al, 2020) and the oceans (Alley et al, 2003; Rahmstorf et al, 2015; Bellomo et al, 2021). The Tsushima warm water (TWW), which occupies the surface layer, flows into the EJS through the Korea Strait and flows out through the Tsugaru and Soya Straits (Cho et al, 2009). The East Sea intermediate water (ESIW), characterized by a vertical salinity minimum, is situated below the. Three deep water masses have been identified below the ESIW (Kim et al, 2004). The vertically homogeneous bottom water (BW) occupies the abyssal layer, and its upper boundary is at approximately 2,500–2,700 m depth (Kim et al, 2004; Talley et al, 2006; Chang et al, 2016; Yoon et al, 2018)
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
