The parameterization IDEMIX for vertical mixing by breaking internal
gravity waves is evaluated in three different non-eddy resolving ocean
models. Three different products of wave forcing by tidal flow over
topography, representing the current uncertainty, are applied and
compared to reference simulations without IDEMIX, allowing the
model-independent effects of the new closure to be assessed. Common to
all models is larger interior mixing work with stronger horizontal
structure due to the inhomogeneous forcing functions in all simulations
using IDEMIX, in better agreement to observations. Coherent model
responses to the stronger mixing work are changes in the thermocline
depth including IDEMIX related to stronger shallow overturning cells in
the Indo-Pacific Ocean. Furthermore, deeper mixed layer depths in the
subpolar North Atlantic are related to an increase of the Atlantic
overturning circulation which brings the model closer to observations,
coming along with an increase in northward heat transport. In the
Southern Ocean, excessive energy input by one of the forcing products
leads to unrealistic deep convection in the Weddell Sea in one of the
models. The deep Indo-Pacific overturning circulation and the bottom
cell of the Atlantic feature an incoherent model response, which may
point towards the importance of excessive numerical mixing in the
models.