Diffusive Staircases in Shear: Dynamics and Heat Transport
Diffusive Staircases in Shear: Dynamics and Heat Transport
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DOI：
10.1175/jpo-d-20-0193.1
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发表时间：
2021-03
影响因子：
3.5
通讯作者：
Justin M. Brown;T. Radko
中科院分区：
文献类型：
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作者：
Justin M. Brown;T. Radko
北极阶梯将热量从大西洋起源的暖水输送到北极混合层的较冷沃茨。出于这个原因，楼梯受到了社会的广泛关注，在没有外部强迫的情况下，楼梯的热传输已经得到了很好的表征。然而，海洋是一个动态的环境，大规模的海流和内波无处不在，即使在被海冰屏蔽的区域也是如此。因此，我们试图解决的影响，背景剪切充分发展的楼梯，使用数值模拟。该代码，这是伪谱，发展的Boussinesq流体的温度和盐度在剪切坐标系中的控制方程。我们发现，与许多其他双扩散系统不同，剪切楼梯需要三维模拟来正确捕捉动态。我们的模拟预测的剪切模式，是一致的观察，并表明，在外部剪切的存在下，楼梯应预计在相应的非剪切系统的效率至少是两倍的热量和盐的运输。这些发现可能会导致全球气候模式中微尺度混合的代表性的重大改进。
Arctic staircases mediate the heat transport from the warm water of Atlantic origin to the cooler waters of the Arctic mixed layer. For this reason, staircases have received much due attention from the community, and their heat transport has been well characterized for systems in the absence of external forcing. However, the ocean is a dynamic environment with large-scale currents and internal waves being omnipresent, even in regions shielded by sea-ice. Thus, we have attempted to address the effects of background shear on fully developed staircases using numerical simulations. The code, which is pseudo-spectral, evolves the governing equations for a Boussinesq fluid with temperature and salinity in a shearing coordinate system. We find that—– unlike many other double-diffusive systems—the sheared staircase requires three-dimensional simulations to properly capture the dynamics. Our simulations predict shear patterns that are consistent with observations and show that staircases in the presence of external shear should be expected to transport heat and salt at least twice as efficiently as in the corresponding non-sheared systems. These findings may lead to critical improvements in the representation of micro-scale mixing in global climate models.