[MITgcm-support] Model blowing due to extreme values

[kunal madkaiker]

Hi All,

I have a model domain at 7km resolution in north Indian ocean with a
southern open boundary. I get an error when the simulation begins.
Error: 'MOM_IMPLICIT_R: error when solving 3-Diag problem.'
Upon further investigation, the error message changes to: 'STOP ABNORMAL
END: S/R MON_SOLUTION, stops due to EXTREME Pot.Temp' ( I did check and
found extreme +ve and -ve values for temperature and salinity at deeper
depths)

>From previous support resolutions, I know it has to do with CFL criteria,
and I have tried changing deltaT, viscAh/viscAhgrid, viscAz, initial
conditions files and even delZ levels. Somehow I am not able to figure it
out.

I have a second question. In calc_oce_mxlayer.F, if I am not mistaken,
model will calc 'hMixCriteria' first and based on its value, will decide to
go for method 1 or 2. If so, how can I set the 2nd method for MLD
calculation?


# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
 &PARM01

## viscAhgrid=9.8E-7,
 viscAh=10.E3,
 viscAz=1.E-4,
## viscAz=1.E-7,
## viscA4=0.,
 diffKhT=1.,
 diffKzT=1.E-5,
## diffK4T=0.,
 diffKhS=1.,
 diffKzS=1.E-5,
## diffK4S=0.,

## useFullLeith=.TRUE.,
## This uses the Strain-Tension form for calculating viscous terms
## useStrainTensionVisc=.TRUE.,

## This is the standard Leith Viscosity coefficient,
## visc=(visc2leith/pi)**3 grad(curl v_h)
## viscC2leith=2.0,

## This is an additional Leith Viscosity, prop to grad(div.v_h)
## It traps instabilities that have no signal in grad(curl v_h)
## viscC2leithD=2.0,

## This is the max Viscosity used, be it Smag or Leith, and it scales
## with grid size and timestep
## viscAhGridMax=1.E-2,
## viscA4GridMax=1.E-9,
##
 no_slip_sides=.FALSE.,
 no_slip_bottom=.TRUE.,
 tempAdvScheme=33,
 saltAdvScheme=33,
 staggerTimeStep=.TRUE.,
#
 tAlpha=2.E-4,
 sBeta =7.E-4,
 gravity=9.81,
 f0=0.0000101456,
 beta=2.2209E-11,
 rigidLid=.FALSE.,
 implicitFreeSurface=.TRUE.,
 implicitDiffusion=.TRUE.,
 implicitViscosity=.TRUE.,
 nonHydrostatic=.FALSE.,
 bottomDragLinear=0.0002,
 eosType='MDJWF',
 useRealFreshWaterFlux=.TRUE.,
 exactConserv=.TRUE.,
## nonlinFreeSurf=4,
## select_rStar=2,
 hFacMin=0.5,
# hFacMinDz=5.,
 hFacInf=0.2,
 hFacSup=2.0,
 useSingleCpuIO=.TRUE
 readBinaryPrec=64,
 writeBinaryPrec=64,
 &

# Elliptic solver parameters
 &PARM02
 cg2dMaxIters=1000,
 cg2dTargetResidual=1.E-13,
 cg3dMaxIters=400,
 cg3dTargetResidual=1.E-13,
## cg2dUseMinResSol=1,
 &

# Time stepping parameters
 &PARM03
 startTime= 0.,
 endTime= 86400.,
 deltaTmom= 180.0,
 deltaTtracer   = 3600.0,
 deltaTClock    = 3600.0,
 deltaTfreesurf = 3600.0,
 pChkptFreq= 86400.,
 dumpFreq= 7200.,
# monitorFreq= 180.0,
 &

# Gridding parameters
 &PARM04
 usingCurvilinearGrid=.FALSE.,
 usingCartesianGrid=.TRUE.,
 usingSphericalPolarGrid=.FALSE.,
 dxSpacing=7695.06,
 dySpacing=7045.008,
 delZ= 5.034 , 10.067 , 10.118 , 10.139 , 10.218 , 10.277 , 10.409 , 10.541
, 10.774 , 11.046,
11.473 , 12.010 , 12.802 , 13.838 , 15.307 , 17.259 , 19.951 , 23.514 ,
28.291 , 34.483,
42.457 , 52.357 , 64.361 , 78.256 , 93.721 , 109.99 , 126.30 , 141.72 ,
155.66 , 167.62,
177.57 , 185.50 , 191.73 , 196.46 , 200.07 , 202.72 , 204.71 , 206.14 ,
207.22 , 207.97,
208.55 , 208.93 , 209.25 , 209.44 , 209.61 , 209.70 , 209.80 , 209.84 ,
209.9,

 radius_fromHorizGrid=6370.E3,
 &

# Input datasets
 &PARM05
 hydrogThetaFile='Twoa_dec_init_UPD_7km.bin',
 hydrogSaltFile='Swoa_dec_init_UPD_7km.bin',
 uVelInitFile='Usoda_dec_init_UPD_7km.bin',
 vVelInitFile='Vsoda_dec_init_UPD_7km.bin',
 bathyFile='bathy_NIO_7km_UPD.bin',
 checkIniTemp=.false.,
 checkIniSalt=.false.,
 &

Kindly advise. Thanks
Kunal
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