[MITgcm-support] Issue with surface ocean currents

[kunal madkaiker]

Dear All,

I am using MITgcm for regional modelling (660x480 gridpoints, 5km
resolution, delZ=5m), over NIO. I simulated the model for 1 year (warm
start), with 3-sided BC and daily EXF forcing.

I am observing more turbulence, and it increases as the simulation
progresses, especially in the latter half of the year. I am also turning
KPP on, and using Leith and Smagorinsky viscosities.

I am attaching a comparison plot of model surface currents with
observation. Can anyone suggest to me why this is happening?

Here is my data file:
# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
 &PARM01
 viscAh=100.,
 viscAz=1.E-5,
 viscA4=0.,
 diffKhT=0.1,
 diffKzT=1.E-5,
 diffK4T=0.,
 diffKhS=0.1,
 diffKzS=1.E-5,
 diffK4S=0.,
#
 useFullLeith=.TRUE.,
 useStrainTensionVisc=.TRUE.,
#
 viscC2leith=0.5,
 viscC4leith=0.05,
#
 viscC2smag=0.5,
 viscC4Smag=0.05,
#
 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.,
 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,

 &

# Time stepping parameters
 &PARM03
 startTime=0.,
 endTime=31536000.,
 deltaTmom=180.0,
 pChkptFreq=31536000.,
 dumpFreq=432000.,
# taveFreq=864000.,
 &

# Gridding parameters
 &PARM04
 usingCurvilinearGrid=.FALSE.,
 usingCartesianGrid=.TRUE.,
 usingSphericalPolarGrid=.FALSE.,
 dxSpacing=5055.960,
 dySpacing=5100.408,
 delZ=  5.0 , 5.0 , 5.0 , 5.0 , 5.0, 5.0 , 5.0 , 5.0 , 5.0 , 5.0,
        5.0 , 5.0 , 5.0 , 5.0 , 5.0, 5.0 , 5.0 , 5.0 , 5.0 , 5.0,
        5.0 , 5.0 , 5.0 , 5.0 , 5.0, 5.0 , 5.0 , 5.0 , 5.0 , 5.0,
        10.0 , 10.0 , 10.0 , 10.0 , 10.0 , 10.0 , 10.0 , 10.0 , 10.0 , 10.0,
        50.0 , 100.0 , 100.0 , 500.0 , 500.0 , 500.0 , 1000.0 , 1000.0 ,
1000.0,

 radius_fromHorizGrid=6370.E3,
 &

# Input datasets
 &PARM05
 hydrogThetaFile='temp_dec_init_5km.bin',
 hydrogSaltFile='salt_dec_init_5km.bin',
 uVelInitFile='U_dec_init_5km.bin',
 vVelInitFile='V_dec_init_5km.bin',
 bathyFile='bathy_BoCo_5km_UPD.bin',
 checkIniTemp=.false.,
 checkIniSalt=.false.,
 &

Thanks,
Kunal
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