[MITgcm-support] Thermodynamical sea ice growth and brine production

Martin Losch Martin.Losch at awi.de
Tue Apr 30 08:39:24 EDT 2013

Polona, I guess you wanted to say that you use the NON-linear free surface, where we (Polona and I) expect that the only salt input is through restoring, but  we see that the diagnostics imply an additional term that we don't understand.

On Apr 30, 2013, at 11:43 AM, Polona Itkin <Polona.Itkin at awi.de> wrote:

> Dear mailing list,
> I m interested in the polynya sea ice production. I d need something like thermodynamical sea ice growth to estimate the volume/winter. I ve found the following diagnostics: 
>    277 |SIdHbOCN|  1 |       |SM      M1|m/s             |HEFF rate of change by ocean ice flux
>    280 |SIdHbATC|  1 |       |SM      M1|m/s             |HEFF rate of change by atm flux over sea ice
>    281 |SIdHbATO|  1 |       |SM      M1|m/s             |HEFF rate of change by open ocn atm flux
>    282 |SIdHbFLO|  1 |       |SM      M1|m/s             |HEFF rate of change by flooding snow
> If i sum up all of them i think i ll get what i want.
> Then i m also interested into the amount of salt that is rejected to the ocean during the sea ice thermodynamical growth. I m using free linear surface and rstar, so technically that would be converting the thermodynamical growth to the freshwater flux. The volume of water from which sea ice is formed is removed from the ocean and the remaining ocean volume has more salt/volume.
> There is already a diagnostic called 
> 266 |SIempmr |  1 |       |SM      U1|kg/m^2/s        |Ocean surface freshwater flux, > 0 increases salt
> and i could use it as some sort of estimate (or checkup) - because it also contains river runoff and evaporation (none of which takes much part in my region/period of interest). But in seaice_growth.F only SIdHbOCN SIdHbATO go to the precipitation. Why not also the other two (SIdHbATO and SIdHbFLO)? Maybe i ve missed something.
> Further more there are:
>     90 |SRELAX  |  1 |       |SM      U1|g/m^2/s         |surface salinity relaxation, >0 increases salt
> and
>     94 |SFLUX   |  1 |       |SM      U1|g/m^2/s         |total salt flux (match salt-content variations), >0 increases salt
> Which should be the same, but are not. Is there any other ocean surface salt flux, but restoring?
> I need to take the restoring term into account to see what kind of salt flux/fw flux effect the polynya has.
> Thank you for your answers!
> Cheers, Polona
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