[MITgcm-support] Underestimated ETA values for Global Ocean!

[Abhisek Chakraborty]

Dear MITgcmUsers,

I am working with global ocean simulation using MITgcm. The "data" file
configuration is

# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
 &PARM01
 tRef = 3*23.,3*22.,21.,2*20.,19.,2*18.,17.,2*16.,15.,14.,13.,
                      12.,11.,2*9.,8.,7.,2*6.,2*5.,3*4.,3*3.,4*2.,12*1.,
 sRef = 50*34.5,
#
 no_slip_sides=.FALSE.,
 no_slip_bottom=.TRUE.,
#
 viscAr= 1.77e-5,
 diffKhT=0.,
 diffK4T=0.,
 diffKrT=1.51e-5,
 diffKhS=0.,
 diffK4S=0.,
 diffKrS=1.51e-5,
#
 viscAh=0.,
 viscAhGrid=0.,
 viscC2Leith=0.,
 viscA4=0.,
 useFullLeith=.TRUE.,
 viscC4Leith=2.0,
 viscC4Leithd=2.0,
 useAnisotropicViscAGridMax=.TRUE.,
 bottomDragQuadratic = 0.002,
#
 tAlpha=2.E-4,
 sBeta =7.4E-4,
 rhonil=1035.,
 rhoConstFresh=1000.,
 gravity=9.81,
 eosType='JMD95Z',
 readBinaryPrec=32,
 writeBinaryPrec=32,
 useSingleCPUio=.TRUE.,
 globalFiles=.TRUE.,
 hFacMinDr=50.,
 hFacMin=0.3,
 implicitDiffusion=.true.,
 implicitViscosity=.true.,
 implicitFreeSurface=.TRUE.,
 useRealFreshWaterFlux=.true.,
 exactConserv=.TRUE.,
 allowFreezing=.TRUE.,
 useCDscheme=.TRUE.,
 useNHMTerms=.TRUE.,
#
 tempAdvScheme=33,
 saltAdvScheme=33,
 StaggerTimeStep=.true.,
 multiDimAdvection=.true.,
 vectorInvariantMomentum=.TRUE.,
 rigidLid=.FALSE.,
 debuglevel=-1
&

# Elliptic solver parameters
 &PARM02
 cg2dMaxIters=500,
 cg2dTargetResidual=1.E-13,
 &

# Time stepping parameters
 &PARM03
# nIter0 =     420,
# nTimeSteps = 3180,
# 100 years of integration will yield a reasonable flow field
 startTime  = 0.,
 endTime    = 15552000000.,
 deltaTmom  = 600.0,
 deltaTtracer= 600.0,
 deltaTClock = 86400.,
 deltaTfreesurf= 600.,
 tauCD =     321428.,
 abEps = 0.1,
 pChkptFreq= 3110400000.,
 dumpFreq=   3110400000.,
 taveFreq=   3110400000.,
 monitorFreq=2592000.,
 &

# Gridding parameters
 &PARM04
 usingSphericalPolarGrid=.TRUE.,
 delR=10.00, 10.00, 10.00, 10.00, 10.00, 10.00, 10.00, 10.01,
 10.03, 10.11, 10.32, 10.80, 11.76, 13.42, 16.04 , 19.82, 24.85,
 31.10, 38.42, 46.50, 55.00, 63.50, 71.58, 78.90, 85.15, 90.18,
 93.96, 96.58, 98.25, 99.25,100.01,101.33,104.56,111.33,122.83,
 139.09,158.94,180.83,203.55,226.50,249.50,272.50,295.50,318.50,
 341.50,364.50,387.50,410.50,433.50,456.50,
 ygOrigin=-80.0,
 dySpacing=1.,
 dxSpacing=1.,
 &

# Input datasets
 &PARM05
 bathyFile=      '../input/bathymetry.bin',
 hydrogThetaFile='../input/lev_t.bin',
 hydrogSaltFile= '../input/lev_s.bin',
 &

and the atmospheric forcings
(atemp,aqh,uwind,vwind,swdown,lwdown,precip,runof,climsst,climsss) are
specified through EXF package. Apart from these I am using GMRedi and KPP
parametrisation schemes. After spinning up the model for 500 years and then
running the model with monthly NCEP fields, I found that temperature,
salinity, currents are matching well with GODAS (NCEP), but surface
elevation (ETA) is underestimated (though the patterns are matching with
GODAS). I have attached one simulation result ( you can see negative
elevation in most of the places). Can anybody please guide me how to
correct this?

Thanking in advance,
Abhisek
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Untitled_eta.gif
Type: image/gif
Size: 317395 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0001.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data.pkg
Type: application/octet-stream
Size: 108 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0004.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data.gmredi
Type: application/octet-stream
Size: 1208 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0005.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data.kpp
Type: application/octet-stream
Size: 182 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0006.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data.exf
Type: application/octet-stream
Size: 9916 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20130316/a46d9916/attachment-0007.obj>