[MITgcm-support] ecco momentum budget

[Matthew Thomas]

Dear all

I am using ecco data and have been having some trouble closing the time-mean
momentum budget. I have been calculating the momentum terms in flux form
according to the description in the MITgcm manual, calculating only the
coriolis, pressure, advection and dissipation terms (neglecting metric terms
on scaling grounds). Unfortunately, the discrepancy between coriolis and
pressure terms is an order of magnitude larger (E-7) than any of the three
remaining terms (E-8).

I have been calculating the coriolis term without considering the CD scheme,
since I do not have D-grid velocities, and have been led to understand this
could be the source of error - I calculate the D-grid velocities by a four
point average of the C-grid. I am however under the impression that on a 15
year time-mean basis this approximation of the D-grid velocities will incur
only a small error. Additionally, I can verify the accuracy of the Coriolis
term by taking the finite difference curl of it (i.e. to get linear
vorticity) and comparing it to the analytical curl - which I have done and
shown to be consistent.

Does anyone have an idea on where my problem is, or have had any similar
problems?

Regards

Matthew



-- 

Matthew Thomas
PhD Student
School of Environmental Sciences
University of East Anglia
NR4 7TJ



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