Laboratoire de Physique des Océans UMR6523 (CNRS, UBO, IFREMER, IRD), IFREMER, Brest, France.
Phys Rev Lett. 2010 May 28;104(21):218501. doi: 10.1103/PhysRevLett.104.218501. Epub 2010 May 25.
We address the problem of cyclone-anticyclone asymmetry in geophysical turbulence using a direct numerical simulation with high Reynolds number Re∼15,000 that includes an active upper boundary and interior dynamics. The regime, characterized by a finite Rossby number (Ro∼0.6) strongly departs from the classical quasigeostrophic regime. The numerical resolution is pushed to the limit of today's supercomputer capabilities ensuring more than two decades free of viscous effects. The results show a strong cyclonic dominance in the upper layers that is stronger for filaments than for vortices. This is in contrast with similar studies that have no active upper boundary which reported either anticyclone dominance or a symmetry between cyclones and anticyclones in the upper layers. This highlights the impact of boundary dynamics on geophysical turbulence.
我们使用具有高雷诺数 Re∼15000 的直接数值模拟来解决地球物理湍流中的气旋反气旋不对称问题，该模拟包括活跃的上边界和内部动力学。该状态的特征是有限的罗斯贝数 (Ro∼0.6)，强烈偏离经典准地转状态。数值分辨率被推到了当今超级计算机能力的极限，确保了超过二十年的无粘性影响。结果表明，在上层中存在强烈的气旋主导地位，对于丝状结构比涡旋更强。这与没有活跃上边界的类似研究形成对比，后者在上层中报告了反气旋主导地位或气旋和反气旋之间的对称性。这突出了边界动力学对地球物理湍流的影响。
