Tidal modulation of two-layer hydraulic exchange flows

[摘要] Time-dependent, two layer hydraulic exchange flow is studied using anidealised shallow water model. It is found that barotropic time-dependentperturbations, representing tidal forcing, increase the baroclinic exchangeflux above the steady hydraulic limit, with flux increasing monotonicallywith tidal amplitude (measured either by height or flux amplitude over atidal period). Exchange flux also depends on the non-dimensional tidalperiod, γ, which was introduced by by Helfrich (1995). When tidalamplitude is characterised by the barotropic flux amplitude, exchange flux is amonotonic function of γ as predicted by Helfrich (1995).However, the relationship between the (imposed) free surface amplitude andflux amplitude is complicated by reflections within the channel and by thebaroclinic response of the two layer system, leading to a non-monotonicrelationship between the height amplitude and γ.

[学科分类] 海洋学与技术