[MITgcm-support] realfreshwaterflux usage in the Arctic

[Jonathan Whitefield]

Hi everyone.

Dimitris Menemenlis and I were discussing the way that the model
receives fresh water this week, and I found out that, for the ECCO2
Arctic face regional configuration, realfreshwaterflux is disabled,
and freshwater is input solely as a salinity anomaly, as opposed to
"normally", where a volume of fresh water is added. I am planning on
doing some runs that look at changes in the Arctic due to river input,
so I have a couple of questions and concerns that I wanted to bring to
the wider community.

First of all, has anyone out there run the Arctic with
realfreshwaterflux enabled? If so, how do I turn it back on. If not,
is it actually possible, or even advisable to re-enable it? What
happens if I change the volume flow of the rivers? Does the fact that
realfreshwaterflux is disabled mean that (for example) doubling the
volume input of a river would have no difference?

Secondly, I was told that when realfreshwaterflux is enabled in the
global model, it adds the volume across the entire ocean at once. This
seems unrealistic to me - how would flow from an Arctic river be added
to a sub-tropical ocean? I would like to be able to have the river
volume be added only where the rivers discharge in to the ocean,
allowing me to look at the effects of changing the discharge on
regional buoyancy driven circulation, so is there an option to disable
this, and have the volume only where it should be?

Apologies for the multitude of questions at once, but hopefully
someone out there has flipped the same switches I want to! Please
contact me if you need clarification on any of my questions, either
through the support list, or personal email.

Thanks!

-- 
Jonathan Whitefield, M.Sc.
Ph.D. Student, Physical Oceanography

110 O'Neill Building,
P.O. Box 757220
University of Alaska Fairbanks
Fairbanks, AK 99775-7220

Phone: (907) 474-5184
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