Chapter 7: APPLICATIONS
well, which has not yet been done. The effects of the diurnal cycle and the
cool skin on the SST, however, have opposite signs and therefore tend to
compensate each other.
Influence of air-bubbles on the fluxes of gases between the atmosphere
and ocean has not yet been properly accounted in gas-exchange
parameterizations. The contribution of the bubble-mediated component into
the total CO 2 transfer between the ocean and atmosphere is, however,
expected to be relatively small on average because CO 2 is a well soluble gas.
7.6.2 Subgrid Scale Mixing Parameterization
a) Vertical mixing
The projection of momentum from the surface wind into the interior of
the ocean depends strongly on the vertical structure of turbulence, which is
only crudely parameterized in coupled climate models, and in many ocean
GCMs. Turbulence from wave-breaking is presently not considered in ocean
models, yet this is a large source of turbulent kinetic energy in the nearsurface layer.
One of the approaches to parameterizing the vertical mixing coefficient
in the ocean is the so-called KPP scheme proposed by Large et al. (1994). A
further development of this approach undertaken in Chapter 3 of this
monograph provides a robust and computationally effective mixing
parameterization scheme.
In some situations (like nighttime convective mixing) nonlocal processes
dominate transport of properties within the upper ocean mixed layer. This
transport is performed by coherent structures considered in Chapter 5 of this
monograph. Incorporation of coherent structures into parameterization
schemes has not yet been done in a systematic way.
b) Horizontal mixing
Horizontal mixing is a complex process including multi-scale nonlinear
interactions. On the submesoscale, horizontal pressure gradients due to
spatially varying buoyancy fields produce quite intensive mixing. Influx of
buoyancy though the air-sea interface is an important component of this
process. In the tropical ocean rainfalls substantially contribute into the
spatial inhomogeneity of buoyancy flux at the air-sea interface. The
horizontal mixing coefficient therefore appears to be intimately linked to
freshwater cycling and salinity effects.
As the spatial resolution of numerical ocean models increases, processes
that were completely unresolved may become partially resolved. Horizontal
mixing is a case in point: When the model grid fully resolves mesoscale
501
well, which has not yet been done. The effects of the diurnal cycle and the
cool skin on the SST, however, have opposite signs and therefore tend to
compensate each other.
Influence of air-bubbles on the fluxes of gases between the atmosphere
and ocean has not yet been properly accounted in gas-exchange
parameterizations. The contribution of the bubble-mediated component into
the total CO 2 transfer between the ocean and atmosphere is, however,
expected to be relatively small on average because CO 2 is a well soluble gas.
7.6.2 Subgrid Scale Mixing Parameterization
a) Vertical mixing
The projection of momentum from the surface wind into the interior of
the ocean depends strongly on the vertical structure of turbulence, which is
only crudely parameterized in coupled climate models, and in many ocean
GCMs. Turbulence from wave-breaking is presently not considered in ocean
models, yet this is a large source of turbulent kinetic energy in the nearsurface layer.
One of the approaches to parameterizing the vertical mixing coefficient
in the ocean is the so-called KPP scheme proposed by Large et al. (1994). A
further development of this approach undertaken in Chapter 3 of this
monograph provides a robust and computationally effective mixing
parameterization scheme.
In some situations (like nighttime convective mixing) nonlocal processes
dominate transport of properties within the upper ocean mixed layer. This
transport is performed by coherent structures considered in Chapter 5 of this
monograph. Incorporation of coherent structures into parameterization
schemes has not yet been done in a systematic way.
b) Horizontal mixing
Horizontal mixing is a complex process including multi-scale nonlinear
interactions. On the submesoscale, horizontal pressure gradients due to
spatially varying buoyancy fields produce quite intensive mixing. Influx of
buoyancy though the air-sea interface is an important component of this
process. In the tropical ocean rainfalls substantially contribute into the
spatial inhomogeneity of buoyancy flux at the air-sea interface. The
horizontal mixing coefficient therefore appears to be intimately linked to
freshwater cycling and salinity effects.
As the spatial resolution of numerical ocean models increases, processes
that were completely unresolved may become partially resolved. Horizontal
mixing is a case in point: When the model grid fully resolves mesoscale
501