Convection: a neglected pathway for downward transfer of wind energy in the oceanic mixed layer -- Journal of Oceanology and Limnology,2018,36(4):1189-1197

	Cite this paper:
	ZHANG Yu, WANG Wei. Convection: a neglected pathway for downward transfer of wind energy in the oceanic mixed layer[J]. Journal of Oceanology and Limnology, 2018, 36(4): 1189-1197

Convection: a neglected pathway for downward transfer of wind energy in the oceanic mixed layer

ZHANG Yu, WANG Wei

Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China

Abstract:

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.

Key words: convective mixed layer|convecting plumes|turbulent kinetic energy (TKE)|wind energy|surface waves

Received: 2017-03-18 Revised:

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