[MITgcm-support] Model based on exp4 experiment - stability problems

[MASSIMO NOVELLO (Yahoo)]

> Please, I will really appreciate if someone can help on what is wrong related to the stability of this model. It is based on exp4 experiment, and I made some changes to reflect a small Lagoon in Rio de Janeiro. If I change delX and delY to 198*1.E2 the model works fine. Also if I only change deltat to 1.E-4, the model also works, but I need more than  5 days to model a 5 days experiment. I tried to apply all the analytics formulas for stability (3.24, 3.25, 3.26, 3.27 and 3.28) and did not found wrong values.
> 
> I’m only looking at the flow when we have a constant wind of 2m/s
> 
> Many thanks,
> Massimo
> 
> # ====================
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
> ################# ARQUIVO PTRACERS_SIZE.h POSSUI VALORES DEFAULT ##############
> 
> &PARM01
> tempStepping=.FALSE., 
> tempAdvection=.FALSE.,
> tempForcing=.FALSE.
> saltStepping=.FALSE.
> saltAdvection=.FALSE.
> saltForcing=.FALSE.
> Tref = 20., 20., 20., 20., 20., 20.,
> sRef = 14., 14., 14., 14., 14., 14.,
> viscAr=1.E-4,
> viscAh=5.E2,
> viscA4=1.E6,
> no_slip_sides=.FALSE.,
> no_slip_bottom=.FALSE.,
> diffKhT=1.E3,
> diffKrT=1.E-5,
> diffKhS=1.E3,
> diffKrS=1.E-5,
> saltAdvScheme=4,
> eosType='LINEAR',
> tAlpha=2.E-4,
> sBeta =0.E-4,
> gravity=9.81,
> f0=1.E-4,
> beta=0.E-11,
> nonHydrostatic=.FALSE.,
> rigidLid=.FALSE.,
> implicitFreeSurface=.TRUE.,
> exactConserv=.TRUE.,
> hFacMin=0.2,
> readBinaryPrec=64,
> globalFiles=.FALSE.,
> useSingleCpuIO=.TRUE.,
> &
> 
> &PARM02
> cg2dMaxIters=1000,
> cg2dTargetResidual=1.E-13,
> cg3dMaxIters=400,
> cg3dTargetResidual=1.E-13,
> &
> 
> &PARM03
> nIter0=0,
> nTimeSteps=432000,
> baseTime=0.,
> deltaT=1,
> startTime=0,
> abEps=0.1,
> momDissip_In_AB=.FALSE.,
> pChkptFreq = 600,
> chkptFreq = 0.0,
> dumpFreq = 20.0,
> monitorSelect = 3,
> monitorFreq = 300000.1,
> 
> periodicExternalForcing=.TRUE.,
> externForcingPeriod=3600.,
> externForcingCycle = 432000.,
> &
> 
> &PARM04
> usingCartesianGrid=.TRUE.,
> delX=198*1.E1,
> delY=210*1.E1,
> delR= 1, 1, 1, 2, 2, 2,
> &
> 
> # Input datasets
> &PARM05
> bathyFile='topog.bump',
> zonalWindFile='wind_x.bin',
> meridWindFile='wind_y.bin',
> &
>