  The NEMO general circulation ocean model is extended to incorporate three
physical processes related to ocean surface waves, namely the surface stress
(modified by growth and dissipation of the oceanic wave field), the turbulent
kinetic energy flux from breaking waves, and the Stokes-Coriolis force.
Experiments are done with NEMO in ocean-only (forced) mode and coupled to the
ECMWF atmospheric and wave models. Ocean-only integrations are forced with
fields from the ERA-Interim reanalysis. All three effects are noticeable in the
extra-tropics, but the sea-state dependent turbulent kinetic energy flux yields
by far the largest difference. This is partly because the control run has too
vigorous deep mixing due to an empirical mixing term in NEMO. We investigate
the relation between this ad hoc mixing and Langmuir turbulence and find that
it is much more effective than the Langmuir parameterization used in NEMO. The
biases in sea surface temperature as well as subsurface temperature are
reduced, and the total ocean heat content exhibits a trend closer to that
observed in a recent ocean reanalysis (ORAS4) when wave effects are included.
Seasonal integrations of the coupled atmosphere-wave-ocean model consisting of
NEMO, the wave model ECWAM and the atmospheric model of ECMWF similarly show
that the sea surface temperature biases are greatly reduced when the mixing is
controlled by the sea state and properly weighted by the thickness of the
uppermost level of the ocean model. These wave-related physical processes were
recently implemented in the operational coupled ensemble forecast system of
ECMWF.
