[MITgcm-support] how to balance the flow flux during preprocessing

[liutongya13 at mails.ucas.ac.cn]

Hi Dustin and David,

Thank you very much for your reply!

I have modified the velocity of N,E,S boundary by multiplying factors that approximately equal to 1 during preprocessing. Thus the net flow flux approach to zero. But a new problem appears.

I use the MITgcm moel to study the effect of Kuroshio on the circulation of South China Sea. The model domain is 0-30N&99-135E, and the resolution is 0.1 degree. The force field contains climatology monthly wind, SST and SSS. The eastern, northern and southern boundary are OBs and the boundary velocity originate from the u and v of HYCOM. The case run for 10 years. The model result can reflect the major features of circulation in this region,such as, NEC, NECC and Kuroshio can be easily recognized. But the details of circulation is different from the real circulation. There are many strange eddies, especially in the interior of SCS. I have no idea what is the problem. Is the setting of OBCS or viscosity parameters inappropriate?

Thanks for any advice!

Tongya Liu

data file:

# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
 &PARM01
 viscAr=1.77E-3,
 viscAh=0,
 diffKhT=0,
 diffKrT=1.51E-5,
 diffKhS=0,
 diffKrS=1.51E-5,
 useFullLeith=.TRUE.,
 viscC4Leith=1.0,
 viscC4Leithd=1.0,
 viscA4GridMax=1.0,

 tempAdvScheme=33,
 saltAdvScheme=33,
 eosType = 'JMD95Z',

 no_slip_sides=.FALSE.,
 no_slip_bottom=.TRUE.,
 bottomDragQuadratic=0.0025,
 implicitDiffusion=.TRUE.,
 implicitFreeSurface=.TRUE.,
 implicitViscosity=.TRUE.,

 staggerTimeStep=.TRUE.,
 implicitFreeSurface=.TRUE.,
 exactConserv=.TRUE.,
 hFacMin=0.1,
 readBinaryPrec=64,
#- not safe to use globalFiles in multi-processors runs
 globalFiles=.TRUE.,
 useSingleCpuIO=.TRUE.,
 &

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

# Time stepping parameters
 &PARM03
 nIter0=       0,
#nIter0=       34560,
 nTimeSteps = 2592000,
#startTime=0.,
#endTime=311040000.,
 basetime=0,
 deltaT=1200.0,
 abEps=0.1,
 momDissip_In_AB=.FALSE.,
 dumpFreq=864000.0,
 pChkptFreq=31104000.,
 chkptFreq=2592000.,
 monitorSelect=2,
 monitorFreq=1200.,

 &

# Gridding parameters
 &PARM04
 usingSphericalPolarGrid=.TRUE.,
 ygOrigin=0.0,
 xgOrigin=99.,
 dxSpacing=0.1,
 dySpacing=0.1,
 delR=30.,30.,30.,30.,30.,30.,
       30.,30.,30.,30.,30.,30.,
       30.,30.,30.,30.,30.,30.,
       30.,30.,50.,50.,100.,200.,
       300.,500.,600.,800.,800.,1000.,
 &
# Input datasets
 &PARM05
 bathyFile='topog.bin',
 hydrogThetaFile='Temp.bin',
 hydrogSaltFile='Salt.bin',
 &





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