A global perspective on Langmuir turbulence in the ocean surface boundary layer
A global perspective on Langmuir turbulence in the ocean surface boundary layer
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DOI：
10.1029/2012gl052932
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发表时间：
2012-09-21
影响因子：
5.2
通讯作者：
Polton, Jeff A.
中科院分区：
文献类型：
--
作者：
Belcher, Stephen E.;Grant, Alan L. M.;Polton, Jeff A.
海洋表层边界层（OSBL）是海洋与大气之间热量和微量气体交换的主要控制层，它位于海洋上层100 m左右，其湍流混合控制着海洋与大气之间的热量和微量气体交换。在这里，我们表明，目前的参数化这种湍流混合导致系统和实质性的误差在全球气候模型中的OSBL的深度，然后导致海表温度的偏差。我们认为，其中一个原因是，目前的参数化缺少关键的表面波过程，迫使朗缪尔湍流加深OSBL比稳定的风强迫更快。缩放参数，以确定两个无量纲参数，测量的重要性，波浪强迫风强迫，并对浮力强迫。一个全球性的角度来看发生的波浪强迫湍流开发使用再分析数据来计算这些参数的全球。这里开发的诊断研究表明，湍流能量可用于混合OSBL被低估，而不强迫表面波。波浪强迫和因此产生的朗缪尔湍流在南大洋的广阔海域和所有季节都很重要。我们的结论是表面波强迫朗缪尔湍流是一个重要的过程中的OSBL，需要参数化。引用：Belcher，S. E、等人（2012年），海洋表面边界层中朗缪尔湍流的全球视角，地球物理学。保留信函：39，L18605，doi：10.1029/2012GL052932。
The turbulent mixing in thin ocean surface boundary layers (OSBL), which occupy the upper 100 m or so of the ocean, control the exchange of heat and trace gases between the atmosphere and ocean. Here we show that current parameterizations of this turbulent mixing lead to systematic and substantial errors in the depth of the OSBL in global climate models, which then leads to biases in sea surface temperature. One reason, we argue, is that current parameterizations are missing key surface-wave processes that force Langmuir turbulence that deepens the OSBL more rapidly than steady wind forcing. Scaling arguments are presented to identify two dimensionless parameters that measure the importance of wave forcing against wind forcing, and against buoyancy forcing. A global perspective on the occurrence of wave-forced turbulence is developed using re-analysis data to compute these parameters globally. The diagnostic study developed here suggests that turbulent energy available for mixing the OSBL is under-estimated without forcing by surface waves. Wave-forcing and hence Langmuir turbulence could be important over wide areas of the ocean and in all seasons in the Southern Ocean. We conclude that surface-wave-forced Langmuir turbulence is an important process in the OSBL that requires parameterization. Citation: Belcher, S. E., et al. (2012), A global perspective on Langmuir turbulence in the ocean surface boundary layer, Geophys. Res. Lett., 39, L18605, doi: 10.1029/2012GL052932.