Abstract
AbstractLarge-scale overturning cells in the ocean typically combine an essentially horizontal surface branch and an interior branch below, where the circulation spans both horizontal and vertical scales. The aim of this study is to analyze the impact of this asymmetry between the two branches by “folding” a one-dimensional thermohaline loop, such that its lower part remains vertical while its upper part is folded down into the horizontal plane. It is found that both the transitory response and the distribution of thermohaline properties are modified significantly when the loop is folded. In some cases, velocity oscillations are induced during the spinup that were not seen in the unfolded case. This is because a circular loop allows for compensations between the density torques produced above and below the heat forcing level, while such compensations are not possible in the folded loop because of the horizontal direction of the surface circulation. Furthermore, the dynamical effects associated with nonlinearities of the equation of state are significantly altered by the folding. Cabbeling tends to decelerate the flow in the folded loop, instead of accelerating it as in the circular case, and can also act to dampen velocity oscillations. Thermobaricity also alters the loop circulation, although comparatively less.
Highlights
Overturning cells of various shapes and sizes are a pervasive feature of the global ocean, ranging from the small eddy-induced circulations to the global-scale meridional overturning circulation (MOC)
Two-dimensional overturning models are often used in the study of horizontal convection, either in numerical simulations or laboratory experiments (Hughes and Griffiths 2008), and, three-dimensional models correspond to the real ocean simulated with general circulation models
We have investigated the effect of this asymmetry on dynamics and fluid properties in the context of a thermohaline loop
Summary
Overturning cells of various shapes and sizes are a pervasive feature of the global ocean, ranging from the small eddy-induced circulations to the global-scale meridional overturning circulation (MOC). The thermohaline loop is a variation of the Stommel box model in which properties can vary continuously along a one-dimensional loop, allowing for a more realistic representation of the advective-diffusive balance (e.g., Welander 1967; Huang 1999; Wunsch 2005). It does find application in physical oceanography but in the form of the so-called thermosyphons in nuclear and solar energy engineering (e.g., Zvirin 1982; Miljkovic and Wang 2011). Thermohaline loops exhibit a variety of dynamical behaviors including instability and chaos (Malkus 1972; Welander 1986; Yuan and Wunsch 2005)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
