[MITgcm-support] Re: question about seaice coupling to

[Dimitris Menemenlis]

> old topic, but what about using some estimate of the Ekman layer depth 
> as the depth for the proxy-geostrophic velocities? The Ekman depth, 
> where according to theory the Ekman spiral has reversed the velocity 
> direction, is sqrt(A_v/(.5*f)). For A_v=1.e-3 (values from the 
> global_ocean.90x40x15/global_ocean.cs32x15), this ranges ranges from 4m 
> in high latitudes to 50m near the equator. Below this depth the wind 
> driven velocity is 36% of the surface value, below twice  this depth it 
> is 14% etc (you know what exponential decay looks like (o: ). So if you 
> use something like 4 or 5 times the Ekman depth, you are well below the 
> Ekman layer (but not necessarily below the mixed layer!).

Martin, do you want to experiment with this and maybe add it
as a runtime option for initialization of pkg/seaice?

The other option of course is to compute surface geostrophic
velocity explicitly from eta.

The whole issue of ice-ocean drag and ice-air drag is treated
in a very primitive way right now.  For example, presence of ice
is ignored for momentum flux to the ocean.

There are many improvements that one could think about
But it would be good if this is done within the context of
detailed model/data comparisons and/or data assimilation.

Cheers, D.

-- 
Dimitris Menemenlis <menemenlis at jpl.nasa.gov>
Jet Propulsion Lab, California Insitute of Technology
MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099
tel: 818-354-1656;  fax: 818-393-6720