On the loss of wind-induced near-inertial energy to turbulent mixing in the upper ocean

Abstract

Wind-induced near-inertial energy has been believed to be an important source for generating the ocean mixing required to maintain the global meridional overturning circulation. In the present study, the near-inertial energy budget in a 1/2° realistic model of the North Atlantic Ocean driven by synoptically varying wind forcing is examined. The authors find that nearly 70% of the wind-induced near-inertial energy at the sea surface is lost to turbulent mixing within the top 200 m and, hence, is not available to generate diapycnal mixing at greater depth. Assuming this result can be extended to the global ocean, it is estimated that the wind-induced near-inertial energy available for ocean mixing at depth is, at most, 0.1 TW. This confirms a recent suggestion that the role of wind-induced near-inertial energy in sustaining the global overturning circulation might have been overemphasized. © 2009 American Meteorological Society.