[MITgcm-support] Underestimated ETA values for Global Ocean!

[Abhisek Chakraborty]

Respected Dr. Dimitris Menemenlis,

Thanks or your prompt reply. I found that my eta is decreasing and salt is
increasing with time. I have set SSS relaxation scale of 36 days (10m depth
for the 1st layer) in my simulation. Can you please suggest me some
suitable scale for SSS relaxation to get a balance for EmPmR imbalance?

regards,
Abhisek

On Sat, Mar 16, 2013 at 5:12 PM, Menemenlis, Dimitris (3248) <
Dimitris.Menemenlis at jpl.nasa.gov> wrote:

>  Hi Abhisek, if you use
> MITgcm_contrib/mitgcm_tools/mitgcmhistory.m
> (or grep) to look at variables dynstat_eta_mean and dynstat_salt_min
> in STDOUT, you will probably find that eta_mean is gradually
> decreasing and salt_min gradually increasing as a function of
> time.  This would mean that EmPmR (evaporation minus precipitation
> minus runoff) is unbalanced in your surface forcing, specifically
> that that there is more evaporation than precipitation and runoff,
> so that your model domain is loosing mass.
> I suggest that you compute this imbalance term and then add it
> to your precipitation.  I'd probably use a global "multiplicative" rather
> "additive" factor to avoid flooding regions that are supposed to
> receive little rain --- although I suspect that this factor will be small
> and that your SSS relaxation term would compensate for any excess
> rain in such regions.
>
>  Cheers, Dimitris
>
>  On Mar 16, 2013, at 2:31 AM, Abhisek Chakraborty wrote:
>
>  After spinning up the model for 500 years and then running the model
> with monthly NCEP fields, I found that temperature, salinity, currents are
> matching well with GODAS (NCEP), but surface elevation (ETA) is
> underestimated (though the patterns are matching with GODAS). I have
> attached one simulation result ( you can see negative elevation in most of
> the places). Can anybody please guide me how to correct this?
>
>
>
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