[MITgcm-support] using RBCS to generate flow

Jean-Michel Campin jmc at ocean.mit.edu
Mon Jan 6 21:25:34 EST 2014


Hi Caroline,

I took a look at your parameter files, but did not find anything
strange.

May be you could send the exact set-up (and indicate the version of the 
MITgcm code you are using) that corresponds to this:
>>A test that really makes me think there is a bug in the rbcs package
>>rather than me doing something stupid is that when I only restore T
>>with a gradient in x, I expect to see a purely baroclinic V develop
>>in geostrophic balance with that. In stead, nothing happens (I can
>>run it for a month, no flow develops at all).
This looks simple enough, and will try to reproduce the problem.

Cheers,
Jean-Michel

On Mon, Jan 06, 2014 at 03:55:36PM +0100, katsman wrote:
> Dear Jean-Michel,
> 
> The files are attached.
> 
> Caroline
> 
> 
> 
> 
> On 12/24/2013 06:00 PM, mitgcm-support-request at mitgcm.org wrote:
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> >    1. Re: using RBCS to generate flow (Jean-Michel Campin)
> >
> >
> >----------------------------------------------------------------------
> >
> >Message: 1
> >Date: Tue, 24 Dec 2013 09:26:52 -0500
> >From: Jean-Michel Campin <jmc at ocean.mit.edu>
> >To: mitgcm-support at mitgcm.org
> >Subject: Re: [MITgcm-support] using RBCS to generate flow
> >Message-ID: <20131224142652.GB19034 at ocean.mit.edu>
> >Content-Type: text/plain; charset=us-ascii
> >
> >Hi Caroline,
> >
> >Could you send few parameter files that you are using when trying to
> >work with checkpoint64 code ?
> >it would be "data", "data.pkg" and "data.rbcs".
> >
> >Cheers,
> >Jean-Michel
> >
> >On Tue, Dec 24, 2013 at 01:54:37PM +0100, katsman wrote:
> >>Dear MITgcm developers,
> >>
> >>Over the past years, I used the RBCS package to generate a flow in
> >>an (otherwise unforced) basin representing the Labrador Sea, by
> >>restoring the flow to a prescibed 3D-temperature and velocity field
> >>in a corner of the basin (T and velocity in geostrophic balance).
> >>This worked excellent in a (admittedly old) checkpoint58-version in
> >>which we manually added a restoring term on U and V analogous to the
> >>programmed T, S part.
> >>
> >>When I got a new workstation I thought it time to upgrade to the
> >>most recent MITgcm version, but I cannot get the package to work in
> >>the same way (and I tried many things over the past months, so I am
> >>getting a bit desperate...).
> >>
> >>The new checkpoint64 is supposed to be able to restore T,U and V,
> >>but I find that - when I prescribe my T,V fields again as before -
> >>in the sponge region defined by the mask, T is restored fine, while
> >>V is restored fine only during the first few timesteps of the
> >>simulation. Then a purely baroclinic U develops as well, while V
> >>becomes barotropic (despite RBCS acting on it). Intriguing, but not
> >>what I wanted.
> >>
> >>A test that really makes me think there is a bug in the rbcs package
> >>rather than me doing something stupid is that when I only restore T
> >>with a gradient in x, I expect to see a purely baroclinic V develop
> >>in geostrophic balance with that. In stead, nothing happens (I can
> >>run it for a month, no flow develops at all).
> >>
> >>One of the earlier versions (c62) has yet another version of the
> >>RBCS package. When I do a test with T-restore only (U,V is not
> >>standard in that one), a baroclinic flow does develop obeying
> >>geostrophy.
> >>
> >>Any ideas what is wrong here? I checked - the  model does frequent
> >>the appropriate lines of code  in rbcs_add_tendency in the c64
> >>version  to change the gV parameter - I suspect somewhere in the
> >>code U and V are mixed up. Notably, the baroclinic flow that
> >>develops in the sponge region is roughly the same strength as the V
> >>I prescribe
> >>
> >>Any ideas?? (if the description is unclear I can send pictures)
> >>
> >>Thanks in advance & happy holidays
> >>Caroline
> >>
> >>
> >>
> >>
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> >
> >
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> >End of MITgcm-support Digest, Vol 126, Issue 44
> >***********************************************
> 

> #; ====================
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
>  &PARM01
> # tRef= 5.367, 4.102, 3.628, 3.447, 3.341, 
> #       3.270, 3.197, 3.156, 3.133, 3.115,
> #       3.096, 3.050, 2.947, 2.781, 2.655,
> # sRef= 15*0.0,
> # normal
>  tRef = 5.36700,4.10200,3.62800,3.44700,3.34100,
>         3.27710,3.21525,3.17308,3.14642,3.12914,
>         3.11629,3.10382,3.08450,3.05690,3.00880,
>         2.95112,2.87507,2.79207,2.72171,2.63647,
> # thick upper layer  - changed  T2+T3
> # tRef = 5.36700,3.92425,3.60538,3.44700,3.34100,
> #        3.27710,3.21525,3.17308,3.14642,3.12914,
> #        3.11629,3.10382,3.08450,3.05690,3.00880,
> #        2.95112,2.87507,2.79207,2.72171,2.63647,
>  sRef= 20*35.0,
>  viscAz=1.E-5,
> # viscAh=40.,
>  viscA4=1.5e09,
>  no_slip_sides=.TRUE.,
>  no_slip_bottom=.TRUE.,
> # diffKhT=20.,
>  diffK4T=0.75e09,
>  diffKzT=1.0e-05,
>  diffKhS=0.0,
>  diffKzS=0.0,
>  f0=1.16e-4,
>  beta=1.4e-11,
>  tAlpha=1.7e-4,
>  sBeta =0.0,
> #gravity=9.81,
>  rigidLid=.FALSE.,
>  implicitFreeSurface=.TRUE.,
> #useCDscheme=.TRUE.,
> #useNHMTerms=.TRUE.,
>  eosType='LINEAR',
>  rhoNil=1028.,
>  hFacMin=0.05,
>  hFacMinDz=50,
> #nonHydrostatic=.TRUE.,
>  readBinaryPrec=64,
>  bottomDragLinear=0.E-4,
>  exactConserv=.TRUE.,
>  &
> 
> # Elliptic solver parameters
>  &PARM02
>  cg2dMaxIters=300,
>  cg2dTargetResidual=1.E-13,
>  cg3dMaxIters=20,
>  cg3dTargetResidual=1.E-8,
>  &
> 
> # Time stepping parameters
>  &PARM03
>  startTime=0,
> # 24 hrs
>  endTime=86400,
> # 3 days
> # endTime=259200,
>  deltaT=600,
>  deltaTtracer=600,
> #deltaTClock =86400.0,
>  abEps=0.01,
> # pChkptFreq=000,
>  chkptFreq=2592000,
> # 1 day
>  dumpFreq=600,
> # 3 day
> #  dumpFreq=259200,
> # dumpFreq=3600,
>  cadjFreq=600,
>  monitorFreq=1.,
>  periodicExternalForcing=.FALSE.,
> # periodicExternalForcing=.TRUE.,
> # 1 / 12 months
> # externForcingPeriod=2592000.,
> # externForcingCycle=31104000.,
>  &
> # Gridding parameters
>  &PARM04
>  usingCartesianGrid=.TRUE.,
> # delZ= 100, 100, 100, 100, 100, 
> #       150, 150, 150, 150, 200, 
> #       225, 275, 350, 400, 450,
> #       
> #       # normal
>  delZ= 100,100,100,100,100,
>        125,125,125,125,125,
>        125,150,150,150,175,
>        175,175,200,250,325,
> # thick upper layer
> # delZ= 150,75,75,100,100,
> #       125,125,125,125,125,
> #       125,150,150,150,175,
> #       175,175,200,250,325,
>  delX=162*7.5e03,
>  delY=210*7.5e03,
>  &
> # Input datasets
>  &PARM05
> # bathyFile = '../INPUT_OCT/topogLS_rbcs_narrow_dijk_steep_7500_64.bin',
>  bathyFile = '../INPUT_OCT/topogLS_rbcs_narrow_dijk_steep_7500_64.bin',
> # surfQfile = '../INPUT_OCT/Qfile_100_7.5km.bin',
> #
> # bathyFile = '../INPUT_IDL/topogLS_rbcs_09_dijk_64.bin',
> # surfQfile = '../INPUT_IDL/Qfile_107_7.5km_64.bin',
>  &
> 

> # RBCS package parameters:
>  &RBCS_PARM01
> #------------------------------------------------------------------------------
> # switches
> #------------------------------------------------------------------------------
>    useRBCtemp=.TRUE.,
>    useRBCvVel=.TRUE.,
>    useRBCuVel=.TRUE.,
> #   useRBCsalt=.TRUE.,
> #------------------------------------------------------------------------------
> #- relaxation times
> #------------------------------------------------------------------------------
>     tauRelaxU=600.,
>     tauRelaxV=600.,
>     tauRelaxT=600.,
> #------------------------------------------------------------------------------
> # masks - #1 and #2 = T,S , #3 = tracers ;
> # masks  U,V have explicit name - if left out then TMask = used
> #------------------------------------------------------------------------------
> # -----OCTAVE VERSION----------------------------
>    relaxMaskFile='../INPUT_OCT/TempMask_7500_north_64_z20.bin','../INPUT_OCT/SaltMask_7500_north_64_z20.bin',
>    relaxMaskUFile='../INPUT_OCT/UvelMask_7500_north_64_z20.bin',
>    relaxMaskVFile='../INPUT_OCT/VvelMask_7500_northeast_64_z20.bin',
> #   
> # -----IDL VERSION
> #   relaxMaskFile='../INPUT_IDL/TempMask_75_east_64_z20.bin','../INPUT_IDL/SaltMask_75_east_64_z20.bin',
> #   relaxMaskVFile='../INPUT_IDL/VMask_75_east_64_z20.bin',
> #------------------------------------------------------------------------------
> # files containing relaxation flds  have explicit name
> #------------------------------------------------------------------------------
> # -----OCTAVE VERSION
>    relaxTFile='../INPUT_OCT/TempFile_7500_drho26_seas055_north_64_z20.bin',
>    relaxUFile='../INPUT_OCT/UvelFile_7500_drho26_seas055_north_64_z20.bin',
>    relaxVFile='../INPUT_OCT/VvelFile_7500_drho26_seas055_north_64_z20.bin',
> #   relaxTFile='../INPUT_OCT/TempFile_7500_drho26_fix_northeast_64_z20.bin',
> #   relaxVFile='../INPUT_OCT/VvelFile_7500_drho26_fix_northeast_64_z20.bin',
> # -----IDL VERSION
> #   relaxTFile='../INPUT_IDL/TempFile_75_drho26_seas100_east_64_z20.bin',
> #   relaxVFile='../INPUT_IDL/VFile_75_drho26_seas100_east_64_z20.bin',
> #------------------------------------------------------------------------------
>    rbcsIniter=0,
> # 1 / 12 months
> #   rbcsForcingPeriod=2592000.,
> #   rbcsForcingCycle=31104000.,
> # 5 / 60 days
>    rbcsForcingPeriod=432000.,
>    rbcsForcingCycle=5184000.,
>  &
> 


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