Impact of wave breaking on upper-ocean turbulence

Abstract

Previous studies have demonstrated that surface wave breaking can impact upper-ocean turbulence through wave-breaking-induced turbulence kinetic energy (TKE) flux and momentum flux. Wave-breaking-induced momentum flux decays approximately exponentially with depth, and the decay exponent depends on both the wind speed and wave age. With increasing wave age, the decay speed of wave-breaking-induced momentum flux first decreases, reaching a minimum around a wave age of 16, and then increases. In this study, a wave-breaking-induced momentum flux parameterization was proposed based on wave age and wind-speed dependence. The new proposed parameterization was introduced into a one-dimensional (1-D) ocean model along with a wave-age-dependent wave-breaking-induced TKE flux parameterization. The simulation results showed that the wave-breaking impact on the ocean mainly affected the upper-ocean layer. Adding the wave-age impact to the wave-breaking-induced TKE flux and momentum flux improved the 1-D model performance concerning the sea temperature. Moreover, the wave-breaking-induced momentum flux had a larger impact on the simulation results than the wave-breaking-induced TKE flux.