Double-Diffusive Intrusions on a Finite-Width Thermohaline Front
Double-Diffusive Intrusions on a Finite-Width Thermohaline Front
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DOI：
10.1175/1520-0485(2004)034
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发表时间：
2004-07
影响因子：
3.5
通讯作者：
J. Simeonov;M. Stern
中科院分区：
文献类型：
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作者：
J. Simeonov;M. Stern
摘要：通过线性理论和使用参数化指状通量的非线性数值计算，研究了叠加在指状有利温跃层上的具有有限宽度L*和总横向盐度变化ΔS的密度补偿温盐锋。通过保留相对较小的分子热扩散以及指努塞尔数 Nu 对密度比的依赖性，表明具有临界 ΔS 的边际稳定性是可能的。横向通量引起平均垂直速度w0(x)，可以锐化锋面，但当ΔS超过一定值时，横向通量的作用超过w0(x)，锋面减弱。非线性二维谱计算表明，平均水平梯度的变化很小，并且即使在产生倾覆之后，入侵仍继续呈指数增长。通过推断翻转阶段之后的线性理论结果，估计入侵速度与 Brunt-Vaisala 成正比……
Abstract A density-compensated thermohaline front with a finite width L∗ and total lateral salinity variation ΔS superimposed on a finger-favorable thermocline is studied by means of linear theory and nonlinear numerical calculations using parameterized finger fluxes. By retaining the relatively small molecular heat diffusion and the dependence of the finger Nusselt number Nu on the density ratio, it is shown that marginal stability with critical ΔS is possible. The lateral fluxes induce a mean vertical velocity w0(x), which can sharpen the front, but when ΔS exceeds a certain value the effect of the lateral fluxes exceeds that of w0(x) and the front weakens. Nonlinear 2D spectral calculations showed that the modification of the mean horizontal gradients is small and that the intrusions continue to grow exponentially even after they have produced overturns. By extrapolating the linear theory results beyond the overturning stage, the intrusion velocity was estimated to be proportional to the Brunt–Vaisala ...