摘要
Upper-ocean turbulent mixing plays a vital role in mediating air-sea fluxes and determining mixed-layer properties, but its energy source, especially that near the base of the mixed layer, remains unclear. Here we report a potentially significant yet rarely discussed pathway to turbulent mixing in the convective mixed layer. During convection, as surface fluid drops rapidly in the form of convective plumes, intense turbulence kinetic energy(TKE) generated via surface processes such as wave breaking is advected downward, enhancing TKE and mixing through the layer. The related power, when integrated over the global ocean except near the surface where the direct effect of breaking waves dominates, is estimated at O(1)TW, comparable to that required by maintaining the Meridional Overturning Circulation(MOC). The mechanism in question therefore deserves greater research attention, especially in view of the potential significance of its proper representation in climate models.
Upper-ocean turbulent mixing plays a vital role in mediating air-sea fluxes and determining mixed-layer properties, but its energy source, especially that near the base of the mixed layer, remains unclear. Here we report a potentially significant yet rarely discussed pathway to turbulent mixing in the convective mixed layer. During convection, as surface fluid drops rapidly in the form of convective plumes, intense turbulence kinetic energy(TKE) generated via surface processes such as wave breaking is advected downward, enhancing TKE and mixing through the layer. The related power, when integrated over the global ocean except near the surface where the direct effect of breaking waves dominates, is estimated at O(1)TW, comparable to that required by maintaining the Meridional Overturning Circulation(MOC). The mechanism in question therefore deserves greater research attention, especially in view of the potential significance of its proper representation in climate models.
作者
张钰
王伟
ZHANG Yu;WANG Wei(Physical Oceanography Laboratory/CIMST,Ocean University of China and Qingdao National Laboratory for Marine Science and Technology,,Qingdao 266071,China)
基金
Supported by the National Basic Research Program of China(973 Program)(No.2015CB954300)
the AoShan Talents Program Supported by Qingdao National Laboratory for Marine Science and Technology(No.2015ASTP-OS02)
the National Natural Science Foundation of China(No.41376011)
关键词
湍流混合
海汽通量
能量
海洋学
convective mixed layer
convecting plumes
turbulent kinetic energy (TKE)
wind energy
surface waves