[MITgcm-support] question about seaice coupling to ocean velocities

[Martin Losch]

Hi,
I may have asked this before, but couldn't find the answers (if there 
where any) in the email archives:
What's the reason for using the third level (k=3) velocities 
u/vVel(i,j,3,bi,bj) as "proxy for geostrophic velocities" in 
seaice_model.F? It is reasonalbe to assume that only the 3rd level 
velocities excert stress on the sea ice from below? If you are willing 
to accept that the surface velocities are too noisy to be used, 
shouldn't the k-level be connected to a certain depth and not to a hard 
coded k-level? I mean, in a coarse model with, say, 50-70m layer 
thickeness (as in global_ocean_90x40x15 and derivatives) this will have 
a completely different effect from a model with resolves the surface 
layers rather well (say 10m in the upper 100m). What's the rationale 
behind the choice of k=3?

Martin