[MITgcm-support] Track freshwater flow from sea ice melting

[Martin Losch]

Hi Yilang,

if you are using seaice_growth (default if you use the pkg/seaice), then this is the only place where sea ice modifies the freshwater flux into the ocean.

The freshwater flux due to ice is (in mass units)

     &         + tmpscal1*convertHI2PRECIP
     &         )*rhoConstFresh

where tmscal1 is the sum of all terms starting in line 2357 is seaice_growth.F
https://github.com/MITgcm/MITgcm/blob/20a156cdcefcb000006123cf7ddac8fc997cb603/pkg/seaice/seaice_growth.F#L2375-2386

Now, some of these contributions are freezing, some are melting, so I would probably save this tmpscal1 in a new 2D field that I pass to pkg/ptracers/ptracers_forcing_surf.F, and you could add this flux only if the sign means melting (i.e. tmpscal1<0).

Martin

> On 19. May 2022, at 18:29, Yilang Xu <yxu at whoi.edu> wrote:
> 
> Hi all, 
>  
> Just follow up on my previous question as I have proceeded from there. The linkage between EmPmR and passive tracer concentration can be formed by modifying pkg/ptracers/ptracers_forcing_surf.F and prescribing PTRACERS_EvPrRn in data.ptracers.
> However, EmPmR is the net freshwater flux, and I need only the contribution of sea ice to freshwater flux. So I look into pkg/seaice/seaice_growth.F, and find that EmPmR is modified there by several terms related to sea ice.
>  
> My question is, is pkg/seaice/seaice_growth.F the only place where EmPmR gets modified and later transferred to pkg/ptracers/ptracers_forcing_surf.F? if that is the case, I can take some variables in seaice_growth.F and use them in ptracers_forcing_surf.F.
>  
> Thanks,
> Yilang 
>  
>  
> From: Yilang Xu <yxu at whoi.edu>
> Date: Friday, April 8, 2022 at 13:23:20
> To: "MITgcm-support at mitgcm.org" <MITgcm-support at mitgcm.org>
> Cc: Yilang Xu <yxu at whoi.edu>
> Subject: Track freshwater flow from sea ice melting
>  
> Dear MITgcm community, 
>  
> I am wondering if there is a way to track the trajectory of the freshwater flow exclusively from sea ice melting. Currently the model outputs net surface freshwater flux (oceFWflx) using diagnostics. But I want to track only the contribution from sea ice melting, and try to link it with ptracers package to add a surface source of passive tracers. Appreciate it if anyone could help to point out which sea ice variable to look into.
>  
> Thanks,
> Yilang 
>  
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