[MITgcm-support] MITgcm-support Digest, Vol 244, Issue 6
赖燕红
yhlai at pku.edu.cn
Tue Oct 17 02:37:46 EDT 2023
Hi Martin,
Thank you very much for your helpful suggestions!
The asymmetry in my results has been removed after I average the theta before the criterion according to your advice.
Yanhong
> -----原始邮件-----
> 发件人: mitgcm-support-request at mitgcm.org
> 发送时间: 2023-10-17 00:00:07 (星期二)
> 收件人: mitgcm-support at mitgcm.org
> 抄送:
> 主题: MITgcm-support Digest, Vol 244, Issue 6
>
> Send MITgcm-support mailing list submissions to
> mitgcm-support at mitgcm.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> or, via email, send a message with subject or body 'help' to
> mitgcm-support-request at mitgcm.org
>
> You can reach the person managing the list at
> mitgcm-support-owner at mitgcm.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of MITgcm-support digest..."
>
>
> Today's Topics:
>
> 1. Re: Asymmetric surface temperature under symmetric forcing
> when rbcs package is used (Martin Losch)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 16 Oct 2023 17:41:57 +0200
> From: Martin Losch <Martin.Losch at awi.de>
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] Asymmetric surface temperature under
> symmetric forcing when rbcs package is used
> Message-ID: <AD5B8961-4568-45D3-8D6F-A41ADE78C8AA at awi.de>
> Content-Type: text/plain; charset="utf-8"
>
> Just a guess:
>
> The MITgcm uses a C-grid, so that the velocities are staggered, i.e. the vVel-points are 1/2 grid cell ?south? of the theta points. If you want to preserve symmetry, you could try to average the theat first to velocity points before evaluating your criterion, e.g.
>
> IF (0.5*(theta(i,j,k,bi,bj)+theta(i,j-1,k,bi,bj)) .LE. 1700.) THEN
> gTendency(i,j) = gTendency(i,j)
> & - RBC_maskV(i,j,k,bi,bj)*rec_tauRlx
> & *( vVel(i,j,k,bi,bj)- RBCvVel(i,j,k,bi,bj) )
> ENDIF
>
> Martin
>
> > On 16. Oct 2023, at 08:05, ??? <yhlai at pku.edu.cn> wrote:
> >
> > Hello everyone!
> >
> > I'm trying to simulate the ocean circulation under a zonally-symmetric surface temperature forcing in a 2D domain (x-z).
> > Surface temperature is relaxed to a prescribed distribution with a timescale of 20000 s, and Ts ranges from 50 K at the east/west boundaries (?120?) to 3000 K at the substellar point (0?).
> > But not sure why, the snapshot temperature and other fields (u, SSH, w) always show asymmetric pattern around the substellar point (Figure 1 attached).
> > I checked the codes and results, and find that the asymmetric results occur after the rbcs package is included and a condition is added in the rbcs_add_tendency.F,this condition is added to reduce the velocity to zero when T<1700 K.
> > IF ( tracerNum.EQ.-2 .AND. useRBCvVel ) THEN
> > rec_tauRlx = rbcsVanishingFac/tauRelaxV
> > DO j=0,sNy+1
> > DO i=0,sNx+1
> > IF (theta(i,j,k,bi,bj) .LE. 1700) THEN
> > gTendency(i,j) = gTendency(i,j)
> > & - RBC_maskV(i,j,k,bi,bj)*rec_tauRlx
> > & *( vVel(i,j,k,bi,bj)- RBCvVel(i,j,k,bi,bj) )
> > ENDIF
> > ENDDO
> > ENDDO
> > ENDIF
> > And there is no asymmetry when rbcs is Off or rbcs is On and the condition is not included under the same thermal forcing.
> >
> > Actually I can't understand the asymmetry in surface temperature, because it should be the same to the prescribed surface forcing, which should not be affected even by the rbcs package?
> >
> > Do you know how to solve this problem? Any suggestions are welcomed!
> > By the way, there are large negative vertical velocity in the west and east boundaries (top right panel; w; Figure 1), I guess it might be induced by numerical problem.If you know the reason please tell me.
> > Thanks very much in advance!
> > And the data.rbcs and data files I used are listed as below:
> >
> > %%%%%%%%%%%%%%%%%%%% data.rbcs # RBCS package parameters:
> > &RBCS_PARM01
> > useRBCuVel=.TRUE.,
> > useRBCvVel=.TRUE.,
> > tauRelaxU=4000.,
> > tauRelaxV=4000.,
> > relaxMaskUFile='U_relax_mask.bin'
> > relaxMaskVFile='V_relax_mask.bin'
> > relaxUFile='U_relax.bin',
> > relaxVFile='V_relax.bin'
> >
> > # Note that U/V_relax_mask = 1.0 everywhere, and U/V_relax = 0.0 everywhere.
> >
> > %%%%%%%%%%%%%%%% some codes in data &PARM01
> > tRef=43*50.,
> > sRef= 43*34.7,
> > cosPower=1.,
> > viscAr=1.E-3,
> > viscAh=12.E5,
> > no_slip_sides=.TRUE.,
> > no_slip_bottom=.TRUE.,
> > bottomDragLinear=1.E-3,
> > diffKhT=1.E3,
> > diffKrNrT=43*1.E-3,
> > ivdc_kappa=100.,
> > implicitDiffusion=.TRUE.,
> > &PARM04
> > usingSphericalPolarGrid=.TRUE.,
> > delRc = 40, 40, 40, 40, 40, 40, 40, 50, 50, 50, 50, 50, 50, 50, 50, 50, 60, 60, 60, 80, 80, 80, 100, 100,
> > 100, 100, 100, 100, 100, 100, 150, 150, 150, 200, 200, 200, 200, 200, 300, 300, 300, 300, 400, 400,
> > rSphere=9E6,
> > xgOrigin=-120.,
> > delY=1*2.5,
> > delX=96*2.5,
> > &
> >
> > # Input datasets
> > &PARM05
> > bathyFile='topo_nx96ny1_5km.bin',
> > thetaClimFile='sst_Tm3000K.bin',
> > &
> >
> >
> > Best regards, Yanhong
> >
> >
> > <Figure 1.png>_______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>
>
> ------------------------------
>
> End of MITgcm-support Digest, Vol 244, Issue 6
> **********************************************
More information about the MITgcm-support
mailing list