[MITgcm-support] heat budget associated with shelfice

[Malte Jansen]

Hi Dan,

I recently used a similar(ish) setup and seemed to be able to close the heat budget. I only looked at the (statistically) steady state though (so there was no column heat budget tendency to speak off, but an accurate balance between heat sources and sinks), and I had SHELFICEboundaryLayer=.false..

The one thing I can think off is that the mass flux associated with melting makes this budget a bit complicated in your case - but I’m not sure how to do it right. Maybe SHlForcT is what you want to compare to?

-Malte





On Oct 1, 2015, at 7:29 AM, Daniel Goldberg <dngoldberg at gmail.com<mailto:dngoldberg at gmail.com>> wrote:

Hello --

I am trying (unsuccessfully) to close the heat budget associated with shelfice melt rates, and am trying to understand what is accounted for in the diagnostic array ShelficeHeatFlux. I think it might be purely diagnostic, is it possible the calculation is out of date?

I have a simplified setting so there are not too many things to take account of. I have constant ice thickness and depth, uniform initial temperature and salinity (that instigates melting, not freezing) and i have set shelficeGammaFrict = .false. so that melting can occur with zero velocity. additionally i have

useRealFreshWaterFlux = .true,
exactConserv=.true.,
SHELFICEconserve = .true.,

I am checking changes over a timestep of a column integral of

heatcapacity_cp * rhoconst * theta

and comparing against

shelficeheatflux*deltaT

for the same column. With  "SHELFICEboundaryLayer=.true.", the agreement is initially very good (on the order of 1 in 10,000). It then steadily diverges though.

(With  "SHELFICEboundaryLayer=.false." the agreement is bad, even in the first few time steps.)

Many thanks
Dan

--

Daniel Goldberg, PhD
Lecturer in Glaciology
School of Geosciences, University of Edinburgh
Geography Building, Drummond Street, Edinburgh EH8 9XP


em: D<mailto:dgoldber at mit.edu>an.Goldberg at ed.ac.uk<mailto:an.Goldberg at ed.ac.uk>
web: http://ocean.mit.edu/~dgoldberg
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