Mesoscale eddies and mixed layer interactions

1
Mesoscale eddies and mixed layer interactions

• Mixed layer and air-sea fluxes
• What about surface waves and their effect on the
  air-sea fluxes?
• Taking into account ocean currents in
  calculating the wind stress?
• Vertical mixing what about Prandtl number?
  Mixing of momentum/vs tracers?

2
Mesoscale eddies

• Mixed layer and mesoscale eddies
• Proper resolution of the seasonal cycle is
  essential. Vertical resolution at the mixed layer
  base?
• Eddy parameterizations in the mixed layer is
  this documented? Do we agree on what to do?

3
Eddy-induced velocities in a zonal channel
Large values of eddy-induced velocity
Treguier, 1999
V (QG) as a function of y and ? The density
domain corresponds to the time-averaged ?.
V (isopycnic) as a function of y and ? The
density domain corresponds to all possible values
of ?.
4
Mesoscale eddy parameterizations
Eddies should mix horizontally in the mixed
layer - Bring the isopycnal slopes to zero
in the mixed layer so that isopycnal mixing of
tracers becomes horizontal (OPA model?) - Set to
zero the coefficients for GM eddy-induced
velocities and for isopycnal mixing (NCAR model?
GFDL?)
5
Quantification of the eddy contribution to
subduction
Maria Valdivieso da Costa et al, Submitted to
JPO (CLIPPER 1/6 model)
Local eddy contribution is locally large but
there is eddy-mean flow cancellation.
6
Quantification of the eddy contribution to
subduction
Maria Valdivieso da Costa et al
Total
Mean flow only