Length scale of the finite-amplitude meanders of shelfbreak fronts
Length scale of the finite-amplitude meanders of shelfbreak fronts
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DOI：
10.1175/jpo-d-14-0249.1
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发表时间：
2015-10
影响因子：
3.5
通讯作者：
W. Zhang;G. Gawarkiewicz
中科院分区：
文献类型：
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作者：
W. Zhang;G. Gawarkiewicz
摘要通过分析论证和数值模型相结合，本研究探讨了陆架坡折带前缘的有限振幅弯曲，其特征是在陆架坡折带的表面和底部都出露倾斜的等密度线。其目的是提供一个公式的曲流长度尺度，可以解释观测到的锋面长度尺度的变化，并与观测进行验证。考虑到锋面不稳定是正压和斜压不稳定的混合，推导出的沿陆架弯曲长度尺度公式为[b1/（1 + a1 S1/2）]NH/f，式中N为浮力频率，H为锋面深度，f为科里奥利参数，S为测量正压和斜压不稳定性能量转换比的伯格数; a1和b1是经验常数。锋面不稳定的初始增长率表示为[b2（1 + a1 S1/2）/（1 + a2αS1/2）]NH/L，其中α为锋面底部坡度，a2和b2为经验常数。
AbstractThrough combining analytical arguments and numerical models, this study investigates the finite-amplitude meanders of shelfbreak fronts characterized by sloping isopycnals outcropping at both the surface and the shelfbreak bottom. The objective is to provide a formula for the meander length scale that can explain observed frontal length scale variability and also be verified with observations. Considering the frontal instability to be a mixture of barotropic and baroclinic instability, the derived along-shelf meander length scale formula is [b1/(1 + a1S1/2)]NH/f, where N is the buoyancy frequency; H is the depth of the front; f is the Coriolis parameter; S is the Burger number measuring the ratio of energy conversion associated with barotropic and baroclinic instability; and a1 and b1 are empirical constants. Initial growth rate of the frontal instability is formulated as [b2(1 + a1S1/2)/(1 + a2αS1/2)]NH/L, where α is the bottom slope at the foot of the front, and a2 and b2 are empirical constants...