[MITgcm-support] Model loosing salt

Tue Apr 26 20:29:50 EDT 2016

Dear Michael,

The temperature and elevation don't show any such decreasing or increasing
trend. Only problem I have noticed is with the salinity.

regards,
Abhisek
On 27-Apr-2016 4:31 AM, "michael schaferkotter" <schaferk at bellsouth.net>
wrote:

> A.
> can you also let us know the same informations for the temperature and
> surface elevation? (ie. mean temperature and mean ssh)
>
> michael
>
> On Apr 26, 2016, at 10:56 AM, Abhisek Chakraborty wrote:
>
> > --===============1524751413==
> > Content-Type: multipart/alternative;
> boundary=001a114dac3897ae8c053165542d
> >
> > --001a114dac3897ae8c053165542d
> > Content-Type: text/plain; charset=UTF-8
> >
> > Dear Martin,
> > Thanks for your prompt response. Surely the atmospheric forcing is adding
> > up non-zero freshwater flux. I have found the mean salinity is also
> > decreasing. I am using OBCS_BALANCE with a non-zero sponge layer. I have
> > tried with and without Orlanski OBC at my southern bounday but the
> results
> > are similar. Is it always required to modify the code for balancing the
> > tracers for a regional configuration of the model despite of using the
> > standard OBCS package?
> > With best regards,
> > Abhisek
> > On 26-Apr-2016 4:54 PM, "Martin Losch" <Martin.Losch at awi.de> wrote:
> >
> >> Abhisek,
> >>
> >> as far as I can see, you have an open boundary and you use atmospheric
> >> surface forcing. Both of them will most likely have non-zero freshwater
> >> flux that will change your mean salinity (btw, does the mean salinity
> also
> >> change, or only the surface salinity as shown in your plots?). You could
> >> balance the surface freshwater flux with a flag (balanceEmPmR=.TRUE.) at
> >> each timestep, but you'd have to code balancing the freshwater flux
> >> (implied salinity flux, salt*vVel) through the open boundary yourself.
> >>
> >> Martin
> >>
> >> On 04/26/2016 11:53 AM, Abhisek Chakraborty wrote:
> >>
> >>> Dear All,
> >>>
> >>> I am trying to configure Mitgcm (version 65r) for Bay of Bengal with a
> >>> constant horizontal resolution of 2km. After 3 years of model runs
> >>> (2013-2015) using daily ERA forcing, I found the model is losing
> >>> salinity. The domain averaged salinity shows a decreasing trend. The
> >>> trend is more prominent for the head Bay. I am using yearly run off
> >>> climatology. A figure is attached to show my model domain and salinity
> >>> trend.
> >>>
> >>> The relevant data files are also attached.  Can anybody please help me
> >>> pointing out the possible causes of this decreasing salinity trend?
> >>>
> >>> Thanking in advance,
> >>> Abhisek
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> MITgcm-support mailing list
> >>> MITgcm-support at mitgcm.org
> >>> http://mitgcm.org/mailman/listinfo/mitgcm-support
> >>>
> >>>
> >> --
> >> Martin Losch
> >> Alfred Wegener Institute for Polar and Marine Research
> >> Postfach 120161, 27515 Bremerhaven, Germany;
> >> Tel./Fax: ++49(0471)4831-1872/1797
> >>
> >>
> >> _______________________________________________
> >> MITgcm-support mailing list
> >> MITgcm-support at mitgcm.org
> >> http://mitgcm.org/mailman/listinfo/mitgcm-support
> >>
> >
> > --001a114dac3897ae8c053165542d
> > Content-Type: text/html; charset=UTF-8
> > Content-Transfer-Encoding: quoted-printable
> >
> > <p dir=3D"ltr">Dear Martin,<br>
> > Thanks for your prompt response. Surely the atmospheric forcing is
> adding u=
> > p non-zero freshwater flux. I have found the mean salinity is also
> decreasi=
> > ng. I am using OBCS_BALANCE with a non-zero sponge layer. I have tried
> with=
> > and without Orlanski OBC at my southern bounday but the results are
> simila=
> > r. Is it always required to modify the code for balancing the tracers
> for a=
> > regional configuration of the model despite of using the standard OBCS
> pac=
> > kage?<br>
> > With best regards,<br>
> > Abhisek</p>
> > <div class=3D"gmail_quote">On 26-Apr-2016 4:54 PM, &quot;Martin
> Losch&quot;=
> > &lt;<a href=3D"mailto:Martin.Losch at awi.de">Martin.Losch at awi.de</a>&gt;
> wro=
> > te:<br type=3D"attribution"><blockquote class=3D"gmail_quote"
> style=3D"marg=
> > in:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Abhisek,<br>
> > <br>
> > as far as I can see, you have an open boundary and you use atmospheric
> surf=
> > ace forcing. Both of them will most likely have non-zero freshwater flux
> th=
> > at will change your mean salinity (btw, does the mean salinity also
> change,=
> > or only the surface salinity as shown in your plots?). You could balance
> t=
> > he surface freshwater flux with a flag (balanceEmPmR=3D.TRUE.) at each
> time=
> > step, but you&#39;d have to code balancing the freshwater flux (implied
> sal=
> > inity flux, salt*vVel) through the open boundary yourself.<br>
> > <br>
> > Martin<br>
> > <br>
> > On 04/26/2016 11:53 AM, Abhisek Chakraborty wrote:<br>
> > <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0
> .8ex;border-left:1p=
> > x #ccc solid;padding-left:1ex">
> > Dear All,<br>
> > <br>
> > I am trying to configure Mitgcm (version 65r) for Bay of Bengal with
> a<br>
> > constant horizontal resolution of 2km. After 3 years of model runs<br>
> > (2013-2015) using daily ERA forcing, I found the model is losing<br>
> > salinity. The domain averaged salinity shows a decreasing trend. The<br>
> > trend is more prominent for the head Bay. I am using yearly run off<br>
> > climatology. A figure is attached to s
>
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
>
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