The impact of surface waves on the mixing of the upper ocean
-
摘要: 本文对N-S方程进行波浪平均,得到一个新的三维数值模型。该模型同时考虑大尺度力“Coriolis-Stokes力”和小尺度力“Stokes-Vortex力”。将三维数值模型应用到海洋模式POM中,选取不同的参数进行理想数值实验。结果表明随着Langmuir数逐渐减小,垂向混合逐渐增强。波浪破碎和Stokes湍效应都能加强垂向混合,但波浪破碎的影响仅仅局限在表层很薄的一层,而Stokes湍效应可以影响到整个混合层。将模型应用于全球大洋,结果发现海洋上层垂向混合加强,垂向混合系数变大,以南极绕极流海域最为明显。研究表明表面波浪对海洋上层混合具有重要作用,进行海洋数值模拟时,需要考虑波浪诱导的混合效应。
-
关键词:
- 表面波浪 /
- Stokes漂流 /
- Langmuir湍效应 /
- 混合
Abstract: A new three-dimensional numerical model is derived through a wave average on the primitive N-S equations, in which both the "Coriolis-Stokes forcing" and the "Stokes-Vortex force" are considered. Three ideal experiments are run using the new model applied to the Princeton ocean model (POM). Numerical results show that surface waves play an important role on the mixing of the upper ocean. The mixed layer is enhanced when wave effect is considered in conjunction with small Langmuir numbers. Both surface wave breaking and Stokes production can strengthen the turbulent mixing near the surface. However, the influence of wave breaking is limited to a thin layer, but Stokes drift can affect the whole mixed layer. Furthermore, the vertical mixing coefficients clearly rise in the mixed layer, and the upper ocean mixed layer is deepened especially in the Antarctic Circumpolar Current when the model is applied to global simulations. It indicates that the surface gravity waves are indispensable in enhancing the mixing in the upper ocean, and should be accounted for in ocean general circulation models.-
Key words:
- surface waves /
- Stokes drift /
- Langmuir turbulence /
- mixing
-
Ardhuin F, Rascle N, Belibassakis K A. 2008. Explicit wave averaged primitive equations using a generalized Lagrangian mean. Ocean Modelling, 20: 35-60, doi:10.1016/j. ocemod. 2007. 07.001 Bi Fan,Wu Kejian, Zhang Yuming. 2012. The effect of Stokes drift on Ekman transport in the open sea. Acta Oceanologica Sinica, 31(6): 12-18, doi: 10.1007/s13131-012-0249-1 Blumberg A F, Mellor G L. 1987. A description of a three-dimensional coastal oceancirculation model, in three-dimensional coastal ocean models. Coastal and Estuarine Study, 4: 1-16 Craig P D, Banner M L. 1994. Modeling wave-enhanced turbulence in the ocean surface layer. Journal of Physical Oceanography, 24(12): 2546-2559 Craik A D. 1977. The generation of Langmuir circulation by an instability mechanism. Journal of Fluid Mechanics, 125: 37-52 Craik A D, Leibovich S. 1976. A rational model for Langmuir circulations. Journal of Fluid Mechanics, 73(3): 401-426 Hasselmann K. 1970. Wave-driven inertial oscillations. Geophysical Fluid Dynamics, 1(3/4): 463-502 Holm D D. 1996. The ideal Craik-Leibovich equations. Physica D, 98(2-4): 415-441 Jenkins A D. 1986. A theory for steady and variable wind-and waveinduced currents. Journal of Physical Oceanography, 16(8): 1370-1377 Kantha L H, Clayson C A. 1994. An improved mixed layer model for geophysical applications. Journal of Geophysical Research, 99(C12): 25235-25266 Kantha L H, C A Clayson. 2004. On the effect of surface gravity waves on mixing in the oceanic mixed layer. Ocean Modelling, 6(2): 101-124 Lane E M, Restrepo J M, McWilliams J C. 2007. Wave-current interaction: a comparison of radiation-stress and vortex-force representations. Journal of Physical Oceanography, 37(5): 1122-1141 Langmuir I. 1983. Surface motion of water induced by wind. Science, 87: 119-123 Lewis D M, Belcher S E. 2004. Time-dependent, coupled, Ekman boundary layer solutions incorporating Stokes drift. Dynamics of Atmospheres and Oceans, 37(4): 313-351 Li M, Garrett C, 1997. Mixed-layer deepening due to Langmuir circulation. Journal of Physical Oceanography, 27(1): 121-132 Li M, Garrett C, Skyllingstad E. 2005. A regime diagram for classifying turbulent large eddies in the upper ocean. Deep Sea Research Part I, 52(2): 259-278 Li Shuang, Song Jinbao, Fan Wei. 2013. Effect of Langmuir circulation on upper ocean mixing in the South China Sea. Acta Oceanologica Sinica, 32(3): 28-33, doi: 10.1007/s13131-013-0285-5 Longuet-Higgins, Stewart R W,. 1960. Changes in the form of short gravity waves on long waves and tidal currents. Journal of Fluid Mechanics, 8: 565-583 Longuet-Higgins, Stewart R W. 1961. The changes in amplitude of short gravity waves on steady non-uniform currents. Journal of Fluid Mechanics, 10: 529-549 Mellor George, Blumberg Alan. 2004. Wave breaking and ocean surface layer thermal response. Journal of Physical Oceanography, 34(3): 693-698 Mellor G L, Yamada T. 1974. A hierarchy of turbulence closure models for planetary boundary layers. Journal of the Atmospheric Sciences, 31(7): 1791-1806 Mellor G L, Ymadaa T. 1982. Development of a turbulence closure model for geophysical fluid problems. Reviews of Geophysics and Space Physics, 20(4): 851-875 McWillianms J C. 1996. Modeling the oceanic general circulation. Annual Review of Fluid Mechanics, 28: 215-248 McWilliams J C, Restrepo J M. 1999. The wave-driven ocean circulation. Journal of Physical Oceanography, 29(10): 2523-2540 McWilliams J C, Sullivan P P. 2001. Vertical mixing by Langmuir circulations. Spill and Science Technology, 6(3-4): 225-238 McWillianms J C, Sullivan P P, Moeng C H. 1997. Langmuir turbulence in the ocean. Journal of Fluid Mechanics, 334: 1-30 McWilliams J C, Testrepo J M, Lane E M. 2004. An asymptotic theory for the ocean. Journal of Fluid Mechanics, 511: 135-178 Newberger P A, Allen J S. 2007a. Forcing a three-dimensional, hydrostatic, primitive-equation model for application in the surf zone: 1. Formulation. Journal of Geophysical Research, 112: C08018, doi: 10. 1029/2006JC003472 Newberger P A, Allen J S. 2007b. Forcing a three-dimensional, hydrostatic, primitive-equation model for application in the surf zone: 2. Application to DUCK94. Journal of Geophysical Research, 112: C08019. doi: 10.1029/2006JC003474 Philips O M. 1977. The Dynamics of the Upper Ocean. Cambridge: Cambridge University Press, 336 Polton J A, Belcher S E. 2007. Langmuir turbulence and deeply penetrating jets in an unstratified mixed layer. Journal of Geophysical Research, 112: C09020, doi: 10. 1029/2007JC004205 Polton J A, Lewis D M, Belcher S E. 2005. The role of wave-induced Coriolis-Stokes forcing on the wind-driven mixed layer. Journal of Physical Oceanography, 35(4): 444-457 Skyllingstad E D, Denbo D W. 1995. An ocean large-eddy simulation of Langmuir circulations and convection in the surface mixed layer. Journal of Geophysical Research, 100(C5): 8501-8522 Smith J. 1998. Evolution of Langmuir circulation during a storm. Journal of Geophysical Research, 103(C6): 12649-12668 Smith J A. 2006. Wave-current interactions in finite-depth. Journal of Physical Oceanography, 36(7): 1403-1419 Smyth W D, Skyllingstad E D, Crawford G B, et al. 2002. Nonlocal fluxes and Stokes drift effects in the K-profile parameterization. Ocean Dynamics, 52(3), 105-115 Sullivan P P, McWilliams J C. 2010. Dynamics of winds and currents coupled to surface waves. Annual Review of Fluid Mechanics, 42: 19-42 Sullivan P P, McWilliams J C, Melville W K. 2007. Surface gravity wave effects in the oceanic boundary layer: large-eddy simulation with vortex force and stochastic breakers. Journal of Fluid Mechanics, 593: 405-452 Stokes G G. 1984. On the theory of oscillatory waves. Trans Cambridge Philosophical Society, 8: 441-455 Uchiyama Y, McWilliams J C. 2008. Infragravity waves in the deep ocean: generation, propagation, and seismic hum excitation. Journal of Geophysical Research, 113: C07029. doi:10.1029 /2007 JC 00 4562 Uchiyama Y, McWilliams J C, Restrepo J M. 2009. Wave-current interaction in nearshore shear instability analyzed with a vortex-force formalism. Journal of Geophysical Research, 114: C06021, doi: 10.1029/2008JC005135 Weber J E. 1983. Steady wind-and wave-induced currents in the open ocean. Journal of Physical Oceanography, 13(3): 524-530 Weber J E. 2003. Wave-induced mass transport in the oceanic surface layer. Journal of Physical Oceanography, 33(12): 2527-2533 Wessel P, Smith W H F. 1996. A global self-consistent hierarchical, high resolution shoreline database. Journal of Geophysical Research, 101(B4): 8741-8743 Wu K J, Liu B. 2008. Stokes drift-induced and direct wind energy inputs into the Ekman layer within the Antarctic Circumpolar Current. Journal of Geophysical Research, 113: C10002, doi: 10. 1029/2007 JC00 4579 Wu K J, Yang Z L, Liu B, et al. 2008. Wave energy input into the Ekman layer. Science in China Series D: Earth Sciences, 51(1): 134-141
点击查看大图
计量
- 文章访问数: 1348
- HTML全文浏览量: 43
- PDF下载量: 1070
- 被引次数: 0