[MITgcm-support] abnormal with extreme temperature value

Martin Losch Martin.Losch at awi.de
Fri Mar 7 03:32:59 EST 2014


Running the (or any) model at high resolution is always a little tricky because of stability. There is the cfl stabilitly for advection and then there are numerical stability criteria for viscosity and diffusion. Please have a look at one of the tutorials, where these numbers a discussed (briefly, e.g. here: <http://mitgcm.org/public/r2_manual/latest/online_documents/node129.html>), or at any numerical modelling textbook, e.g. Steve Griffies’ book on Ocean Climate Modeling.

I think that this
>  viscAh=4.E2,
>  diffKhT=4.E2,
>  diffKhS=4.E2,
is the problem. I suggest to use a different set of parameters:
 viscAhGrid = 0.1,
# you’ll have to play a little with this parameter, but see pkg/mom_common/mom_calc_visc.F for more explanation, or the documentation <http://mitgcm.org/public/r2_manual/latest/online_documents/node85.html> for more options. Using the Leigth scheme is usually a good choice, which will allow you to run with probably the largest time steps possible
 diffKhT = 0.,
 diffKhS = 0., 
# that’s right, no explicit diffusion but then use a stable advection scheme with numerical diffusion to stabilize the run:
 tempAdvScheme = 33,
 saltAdvScheme = 33,
 staggerTimeStep = .TRUE.
# this is the DST3 scheme with flux limiting, see documentation. 

with these parameters, I am guess that you should be able to run with time steps timeStep = 600., or even more. (don’t use deltaTmom/deltaTtracer).

Martin

On Mar 7, 2014, at 8:56 AM, 李志远 <oceanlizy at 163.com> wrote:

> From: Li zhiyuan <oceanlizy at 163.com
> >
> To: MITgcm <
> mitgcm-support at mitgcm.org
> >
> 
> Subject:"abnormal with extreme temperature value "
> 
> Hi,all;
>      I am running a model of semi-enclosed domain with 134x165x16 grid points . the model is driven by surface wind and heat flux .when I run my mitgcm model for some steps , very large temperature values occur ,then the model blows up .
>     the STDOUT file is as below :
> (PID.TID 0005.0001) %MON time_tsnumber                =                   163
> (PID.TID 0005.0001) %MON time_secondsf                =   7.0416000000000E+06
> (PID.TID 0005.0001) %MON dynstat_eta_max              =   7.4690610491135E-01
> (PID.TID 0005.0001) %MON dynstat_eta_min              =  -4.1593172249303E+00
> (PID.TID 0005.0001) %MON dynstat_eta_mean             =   2.0772424301492E-02
> (PID.TID 0005.0001) %MON dynstat_eta_sd               =   4.9627339137015E-01
> (PID.TID 0005.0001) %MON dynstat_eta_del2             =   7.4943932050348E-04
> (PID.TID 0005.0001) %MON dynstat_uvel_max             =   3.5280025421360E+00
> (PID.TID 0005.0001) %MON dynstat_uvel_min             =  -1.4035655480410E+00
> (PID.TID 0005.0001) %MON dynstat_uvel_mean            =  -1.8326591842827E-02
> (PID.TID 0005.0001) %MON dynstat_uvel_sd              =   4.5870513051871E-02
> (PID.TID 0005.0001) %MON dynstat_uvel_del2            =   9.8327354406657E-05
> (PID.TID 0005.0001) %MON dynstat_vvel_max             =   2.4380767316715E+00
> (PID.TID 0005.0001) %MON dynstat_vvel_min             =  -2.3087621147168E+00
> (PID.TID 0005.0001) %MON dynstat_vvel_mean            =   3.4329723926579E-02
> (PID.TID 0005.0001) %MON dynstat_vvel_sd              =   9.0964738317473E-02
> (PID.TID 0005.0001) %MON dynstat_vvel_del2            =   1.9834779107181E-04
> (PID.TID 0005.0001) %MON dynstat_wvel_max             =   2.6286782112003E-02
> (PID.TID 0005.0001) %MON dynstat_wvel_min             =  -9.6061814986124E-02
> (PID.TID 0005.0001) %MON dynstat_wvel_mean            =   3.6700902646170E-05
> (PID.TID 0005.0001) %MON dynstat_wvel_sd              =   3.4462742242225E-03
> (PID.TID 0005.0001) %MON dynstat_wvel_del2            =   7.4810854960120E-06
> (PID.TID 0005.0001) %MON dynstat_theta_max            =   5.7517891007917E+01
> (PID.TID 0005.0001) %MON dynstat_theta_min            =  -1.0228097331456E+03
> (PID.TID 0005.0001) %MON dynstat_theta_mean           =   7.8087020365565E+00
> (PID.TID 0005.0001) %MON dynstat_theta_sd             =   6.2079576234231E+00
> (PID.TID 0005.0001) %MON dynstat_theta_del2           =   1.3811582622522E-02
> (PID.TID 0005.0001) %MON dynstat_salt_max             =   3.5000000000152E+01
> (PID.TID 0005.0001) %MON dynstat_salt_min             =   3.4999999953140E+01
> (PID.TID 0005.0001) %MON dynstat_salt_mean            =   3.4999999999999E+01
>  
> my data file :
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
>  &PARM01
>  tRef = 16*20.,
>  sRef = 16*35.,
>  viscAz=1.E-4,
>  viscAh=4.E2,
>  diffKhT=4.E2,
>  diffKzT=3.E-5,
>  diffKhS=4.E2,
>  diffKzS=3.E-5,
>  rhoConst=1035.,
>  rhoConstFresh=1000.,
>  eosType = 'LINEAR',
>  ivdc_kappa=10.,
>  implicitDiffusion=.TRUE.,
>  allowFreezing=.FALSE.,
>  exactConserv=.TRUE.,
>  hFacMin=.3,
>  readBinaryPrec=32,
>  &
> 
> # Elliptic solver parameters
>  &PARM02
>  cg2dMaxIters=500,
>  cg2dTargetResidual=1.E-13,
>  &
> 
> # Time stepping parameters
>  &PARM03
>  nIter0 =      0,
>  nTimeSteps = 200,
>  deltaTmom = 30.,
>  deltaTtracer = 1200.,
>  deltaTClock  = 43200.,
>  abEps = 0.1,
>  dumpFreq=   864000.,
>  monitorFreq=1.,
>  &
> 
> # Gridding parameters
>  &PARM04
>  usingSphericalPolarGrid=.TRUE.,
>  delz= 10,20,25,30,50,100,100,
>         200,300,400,500,500,500,
>         500,500,500,
>  ygOrigin=24.500,
>  xgOrigin=117.525,
>  delX=134*0.1,
>  delY=165*0.1,
>  &
> 
> # Input datasets
>  &PARM05
>  bathyFile=      'topo.bin',
>  hydrogThetaFile='t16.bin',
> # hydrogSaltFile= 'Lev_clim_salt.bin',
> # zonalWindFile=  'Taux.bin',
> # meridWindFile=  'Tauy.bin',
> #thetaClimFile=  'SST.bin',
> # saltClimFile=   'SSS.bin',
>  &
> 
> I guess it  blow up because  mixing coefficients or advection scheme in my model  is incorrect , how I can avoid such problems ?
> 
> any quick reply is great appreciated !
> lizhi
> 
> 
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