[MITgcm-support] Solar Radiation in pkg/aim_v23

[Jean-Michel Campin]

Hi Fisher,

There is some code in pkg/aim_v23 that allows to specify the obliquity as an input parameter
in file "data.aimphys", but it's still a circular orbit (no eccentricity, no precession).

To specify the obliquity, need to compile with
#define ALLOW_INSOLATION
in AIM_OPTIONS.h

And the obliquity parameter is "OBLIQ" that can be specify in "data.aimphys", 
in namelist "AIM_PAR_FOR".

Cheers,
Jean-Michel

On Sat, May 10, 2025 at 04:38:05AM +0000, ht wrote:
> Hello,
> 
> Sorry for the confusion in my previous message ??? I had misunderstood and assumed that orbital forcing could be imposed as a timeseries file, similar to SST forcing. After checking the code, I found that incoming solar radiation is computed internally in pkg/aim_v23/phy_radiat.F.
> 
> Since I am trying to perform paleoclimate modeling, I would like to ask the following:
> Is there a way in MITgcm to vary the orbital forcing (e.g., obliquity, eccentricity, and precession) over time during a simulation, or alternatively, to specify different orbital parameters for each simulation run?
> 
> Thank you very much for your guidance and assistance.
> 
> Best regards,
> Fisher
> 
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> > 1. Using Solar Radiation Data as Boundary Condition in AIM+OCN
> > Coupled Simulation (ht)
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> > Message: 1
> > Date: Sat, 03 May 2025 12:24:36 +0000
> > From: ht ht.fisher at protonmail.com
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> > To: "MITgcm-support at mitgcm.org" MITgcm-support at mitgcm.org
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> > Subject: [MITgcm-support] Using Solar Radiation Data as Boundary
> > Condition in AIM+OCN Coupled Simulation
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> > Hello,
> >
> > I am currently working on a coupled simulation by modifying the cpl_aim+ocn case from the verification directory. I would like to use solar radiation data as a boundary condition instead of SST or LST.
> >
> > However, I am unsure about the correct approach. I tried enabling shortwave heating by #define SHORTWAVE_HEATING for the atmosphere, but this does not seem appropriate, as the surfQsw file appears to represent the net shortwave flux at the sea surface.
> >
> > Could you please advise me on the proper way to use solar radiation data as a boundary condition?
> >
> > Thank you very much for your time and assistance.
> >
> > Best regards,
> > Fisher
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