[MITgcm-support] 2D boundary conditions at the poles

Jean-Michel Campin jmc at ocean.mit.edu
Sat Nov 12 22:57:56 EST 2011


Hi Angela,

I would propose to try to use Shap_funct=2 (this is the default)
instead of Shap_funct=4.
In addition, you could try to specify a time-scale (the default
is to use the model time-step), the longer it is, the weaker
is the filtering. You could start for example with 10 times deltaT:
 Shap_Trtau=150.,
 Shap_uvtau=150.,
(since deltaT=15.)

Cheers,
Jean-Michel

On Sat, Nov 12, 2011 at 11:47:53AM -0500, Angela Marie Zalucha wrote:
> A figure of surface pressure (eta + Ro_SeaLevel) vs. latitude is
> attached. My data file is below.
> 
> # ====================
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
>  &PARM01
>  tref=48.2417,48.388,48.6109,48.9495,49.4687,50.2756,51.5217,53.239,
>       55.3375,57.8211,60.7092,64.0167,67.7569,71.9439,76.5962,81.74,
>       87.413,93.6712,100.6,108.332,117.086,127.225,139.377,154.64,
>       174.981,203.995,248.46,321.723,453.693,746.463,
>  sRef=30*0.,
> #viscAr=0.E1,
>  viscAh=0.E6,
>  viscA4=0.E17,
>  no_slip_sides=.FALSE.,
>  no_slip_bottom=.FALSE.,
>  diffKhT=0.E3,
>  diffKrT=0.,
>  diffK4T=0.E17,
>  diffKrS=0.E2,
>  diffKhS=0.E3,
>  diffK4S=0.E17,
>  buoyancyRelation='ATMOSPHERIC',
>  eosType='IDEALGAS',
>  omega=-1.13856E-5,
>  exactConserv=.TRUE.,
>  gravity=0.63,
>  rhonil=1.0,
>  rhoConst=1.0,
>  rigidLid=.FALSE.,
>  uniformLin_PhiSurf=.FALSE.,
>  nonlinFreeSurf=4,
>  select_rStar=2,
>  implicitFreeSurface=.TRUE.,
>  staggerTimeStep=.TRUE.,
>  readBinaryPrec=64,
>  writeBinaryPrec=64,
>  hFacMin=1.0,
> # vectorInvariantMomentum=.TRUE.,
> #- not safe to use globalFiles in multi-processors runs; set instead useSingleCpuIO
>  useSingleCpuIO=.TRUE.,
>  atm_Cp = 1043.,
>  atm_Po =  1.4,
>  atm_Cp = 1043.,
>  atm_Po =  1.4,
>  atm_kappa=0.2857142885714,
>  atm_L=253000.,
>  lengthOfDayInSeconds=551893.,
> # Buie, tholen, and wasserman 1997 albedo
> # albedoland = 0.5,
> # albedoice = 0.5,
>  albedoland=0.,
>  albedoice=0.,
>  radcode = 6,
>  lsIsConstant = 0,
>  lsperpetual = 3.141593,
>  eccentricity = 0.251,
>  semimajoraxis = 5.934632E12,
>  lsp = 3.24383404117,
>  axialTilt = 1.05434,
>  solarconstant = 0.864465,
>  tauoo = 2.,
> # radTimeStep = 21600.,
>  radTimeStep = 15.,
>  lsStart = 2.5688,
>  hstauawarm=22075.7,
>  hstauswarm=22075.7,
>  hstauacold=22075.7,
>  hstauscold=22075.7,
>  emissivityOfIce=1.0,
>  emissivityOfLand=1.0,
>  allowDiurnal=0,
>  betacab=0.05,
>  tauinfcab=0.1,
>  useCaballero=0,
>  referenceTempInFrostEqn=35.,
>  referencePresInFrostEqn=0.3,
>  initemp=110.,
>  gamma0=0.01,
>  &
> 
> # Elliptic solver parameters
>  &PARM02
>  cg2dMaxIters=600,
>  cg2dTargetResidual=1.E-13,
>  &
> 
> # Time stepping parameters
>  &PARM03
>  niter0=0,
> # nTimeSteps=31104000,
> # nTimeSteps=69465600,
>  nTimeSteps=71539200,
> #endTime=864000.0,
>  abEps=0.1,
>  deltaT=15.,
>  cAdjFreq=0.,
>  pChkptFreq=466560000.,
>  chkptFreq=0.0,
>  dumpFreq=7776000.,
> #  dumpFreq=2000.,
> # dumpFreq=518400.,
> #dumpFreqFast=39750.,
> #dumpFreqFastStart=5326500.,
>  monitorFreq=7776000.,
> # monitorFreq=2000.
> # monitorFreq=50.,
>  taveFreq=0.,
> #tave_lastiter=1.,
> #tave_lastiter=1.,
>  &
> 
> # Gridding parameters
>  &PARM04
>  usingSphericalPolarGrid=.TRUE.,
>  delX=1*2.8125,
>  delY=64*2.8125,
>  delR=0.0244849394,0.0364268333,0.0525751970,0.0746640152,0.1034712424,
>       0.1382839394,0.1679554545,0.1557584848,0.1340775758,0.1112777273,
>       0.0898157273,0.0711273182,0.0555934697,0.0431052576,0.0332630455,
>       0.0256038788,0.0196925909,0.0151563788,0.0116906364,0.0090528773,
>       0.0070505591,0.0055292258,0.0043596742,0.0034272000,0.0026279697,
>       0.0018837212,0.0011799030,0.0005905985,0.0002190777,0.0000554814,
>  Ro_SeaLevel=1.4,
> # don't change rSphere, because tiles are calculated using this number
>  rSphere=1180.E3,
>  ygOrigin=-90.,
>  &
> 
> # Input datasets
>  &PARM05
>  topoFile='topo.cs.bin',
> # topoTextFile='plutotopo.txt',
>  &
> 
> 
> 
> 
> 
> On Sat, 12 Nov 2011, Jean-Michel Campin wrote:
> 
> >Hi Angela,
> >
> >Could you send the complete parameter file "data" ? might be useful
> >to figure out what is the problem. Also, a plot of Eta function
> >of latitude would be nice.
> >
> >Cheers,
> >Jean-Michel
> >
> >On Thu, Nov 10, 2011 at 06:34:34PM -0500, Angela Marie Zalucha wrote:
> >>Hi,
> >>
> >>I am running the MIT GCM in 2D for the atmosphere (latitue and r*
> >>coordinates).  When I look at eta vs. latitue, I get a very huge
> >>spike in the second to last gridpoint from the poles.  I believe it
> >>is numerical and not physical.  I was wondering what the boundary
> >>conditions are at the poles and how to explain it.
> >>
> >>Here's what I have for the horizontal grid:
> >>usingSphericalPolarGrid=.TRUE.,
> >> delX=1*2.8125,
> >> delY=64*2.8125,
> >> ygOrigin=-90.,
> >>
> >>The pressure is extremely low because this is Pluto!
> >>Ro_SeaLevel=1.6,
> >>rSphere=1180.E3,
> >>
> >>I have seen that the Shapiro filter can affect numerical spikes in
> >>eta in other 2D planets, but haven't been able to modify it
> >>successfully here. Here's my data.shap :
> >> &SHAP_PARM01
> >> shap_filt_uvStar=.FALSE.,
> >> shap_filt_TrStagg=.TRUE.,
> >> Shap_funct=4,
> >> nShapT=4,
> >> nShapUV=4,
> >>
> >>Does anybody have any ideas?
> >>
> >>   Angela
> >>
> >>
> >>
> >>_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> >>Angela Zalucha, Ph.D.
> >>Postdoctoral Associate
> >>Department of Earth, Atmospheric,
> >>  and Planetary Sciences
> >>Massachusetts Institute of Technology
> >>
> >>Office located at Southwest Research Institute
> >>1050 Walnut Street, Suite 300
> >>Boulder, CO 80302
> >>USA
> >>(720) 208-7211
> >>
> >>
> >>http://web.mit.edu/azalucha/www/index.html
> >>_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> >>
> >>
> >>
> >>
> >>_______________________________________________
> >>MITgcm-support mailing list
> >>MITgcm-support at mitgcm.org
> >>http://mitgcm.org/mailman/listinfo/mitgcm-support
> >
> >_______________________________________________
> >MITgcm-support mailing list
> >MITgcm-support at mitgcm.org
> >http://mitgcm.org/mailman/listinfo/mitgcm-support
> >
> 
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> Angela Zalucha, Ph.D.
> Postdoctoral Associate
> Department of Earth, Atmospheric,
>   and Planetary Sciences
> Massachusetts Institute of Technology
> 
> Office located at Southwest Research Institute
> 1050 Walnut Street, Suite 300
> Boulder, CO 80302
> USA
> (720) 208-7211
> 
> 
> http://web.mit.edu/azalucha/www/index.html
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> 
> 


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