The Relative Influence of Diapycnal Mixing and Hydrologic Forcing on the Stability of the Thermohaline Circulation
The Relative Influence of Diapycnal Mixing and Hydrologic Forcing on the Stability of the Thermohaline Circulation
复制标题
底密混合和水文强迫对温盐环流稳定性的相对影响
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
R. Huang
中科院分区：
文献类型：
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作者：
Jubao Zhang;R. Schmitt;R. Huang
摘要在两种表面边界条件下，对海洋热盐环流进行了尺度分析：(i)在“松弛”条件下（海表温度和盐度松弛到规定值），经向翻转（和向极地热输送）对内环流扩散率有三分之二的幂律依赖性。对于任何给定的外部强迫，温盐环流只有一种平衡状态。㈡在“混合”边界条件下（温度放宽到规定值，盐度采用虚拟盐通量条件），可以实现多重平衡。对于给定的热强迫，多重平衡的存在取决于底流扩散系数和水文强迫的相对贡献：对于每一个底流扩散系数K，存在一个阈值淡水通量Ec = CK2/3 （C为常数），低于该阈值，可能存在三种模式，即稳定热模式、不稳定热模式和稳定热模式。
Abstract Scaling analysis of the oceanic thermohaline circulation has been done under two types of surface boundary conditions: (i) Under “relaxation” conditions (sea surface temperature and salinity are relaxed to prescribed values), there is a two-thirds power law dependence of the meridional overturning (and the poleward heat transport) on the diapycnal diffusivity. For any given external forcing, there is only one equilibrium state for the thermohaline circulation. (ii) Under “mixed” boundary conditions (temperature is relaxed to prescribed values and a virtual salt flux condition is used for salinity), multiple equilibria become possible. For a given thermal forcing, the existence of multiple equilibria depends on the relative contributions of diapycnal diffusivity and the hydrologic forcing: for each diapycnal diffusivity K, there is a threshold freshwater flux Ec = CK2/3 (C is a constant) below which three modes are possible with one stable thermal mode, one unstable thermal mode, and a stable hali...