[MITgcm-support] Momentum Budget

[Christopher Piecuch]

All,

There have been some emails going around over the past couple of months 
(and years) regarding closure of momentum budgets using MITgcm. I have 
another question on this topic, if anyone still has energy for this issue.

I am trying to close offline the momentum budgets on an LLC grid using 
the general setup for the upcoming ECCO-Production (Version 4) release. 
I am diagnosing the budget using 64-bit output following methods spelled 
out in Jean-Michel's most recent post on this issue 
(http://mitgcm.org/pipermail/mitgcm-support/2013-December/008719.html) as

TOTUTEND/86400 = -gravity*d(SSH)/dx + Um_dPHdx + Um_Advec + Um_Diss + 
Um_Ext + AB_gU + Implicit Vertical Diffusion,

where SSH = ETAN + sIceLoad/rhoConstFresh and I'm computing the 
horizontal gradients in the SSH using Gael Forget's gcmfaces package.

I'm finding that the correspondence between right-hand and left-hand 
sides of the above equation seems to degrade with depth and proximity to 
sea-ice.

Since the setup I am considering uses the vector-invariant momentum 
equations (vectorInvariantMomentum=.TRUE.), and not the flux-form 
version that seems to be the topic of all previous threads, I am 
wondering: are there additional terms that need to be output to diagnose 
the momentum budgets for the vector-invariant case?

If not, it is probably the case I have some bugs in my post-processing code.

Any input would be appreciated. Please let me know any setup files, 
etc., that might be needed to help diagnose the issue.

Thanks very much in advance,
Chris

-- 
Christopher G. Piecuch, Staff Scientist
Atmospheric and Environmental Research (AER), a Verisk Analytics company
131 Hartwell Avenue, Lexington, MA 02421 USA
p: +1.781.761.2349 | email: cpiecuch at aer.com | www.aer.com