[MITgcm-devel] recent changes in model/scr

[Martin Losch]

Hi Jean-Michel,

I have a simple channel configuration with ice, where I start from some initial velocity field and  basically turn off the ocean dynamics (mom/temp/saltStepping = .false.), and let the ice evolve. This configuration is used in a manuscript (Losch+Danilov, I told you about it, it will appear soon in Ocean Modelling, finally). 
Ironically, now that this manuscript is finally accepted, I cannot reproduce the results with the latest code (the model blows up very quickly). I think I have isolated the change that did it. With checkpoint63e things still work, but after changing integr_continuity (I updated starting from checkpoint63e, timestep.F calc_g[s,t,w].F thermodynamics.F adams_bashforth?.F the_main_loop.F, then diags_rho.F do_oceanic_phys.F set_parms.F config_summary.F (and PARMS.h), no problem, but then momentum_correction_step.F initialise_varia.F integr_continuity.F, forward.F), the problem starts.

Where does my configuration (with mom/temp/saltStepping = .false.) care about changes in the ocean? I have no clue, do you?

Martin

# ====================
# | Model parameters |
# ====================
#
# Continuous equation parameters
 &PARM01
 tRef = 3*-1.9,
 sRef = 3*34.,
 viscAr=1.E-3,
 viscAh=0.E4,
 diffKhT=0.0,
 diffKrT=3.E-5,
 diffKhS=0.0,
 diffKrS=3.E-5,
 rhonil=1035.,
 gravity=9.81,
 eosType = 'MDJWF',
 f0 = 0.0e-4,
 beta = 0.,
 implicitDiffusion=.TRUE.,
 implicitViscosity=.TRUE.,
#useOldFreezing=.TRUE.,
 exactConserv = .true.,
#useRealFreshWaterFlux=.true.,
 useRealFreshWaterFlux=.false.,
#convertFW2salt = -1.,
#useCDscheme=.TRUE.,
 useNHMTerms=.TRUE.,
# turn on looped cells
 hFacMin=.1,
 hFacMindr=20.,
# set precision of data files
 readBinaryPrec=64,
 momStepping = .false.,
 tempStepping= .false.,
 saltStepping= .false.,
# use a flux-limiting advection scheme to avoid overshoots
#tempAdvScheme = 77,
#saltAdvScheme = 77,
 useSingleCPUio = .true.,
 debuglevel=-1,
 &

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

# Time stepping parameters
 &PARM03
 niter0 = 0,
#niter0 = 864000,
#niter0 = 36000,
#ntimeSteps = 864000,
 ntimeSteps = 10,
# 100 years of integration will yield a reasonable flow field
#startTime  =          0.,
#endTime    = 31104000.E1,
#endTime    = 62208000.E2,
#deltaT    = 600.,
 deltaT = 3600.0,
 abEps = 0.1,
 forcing_In_AB  = .false.,
 pChkptFreq= 311040000.,
 dumpFreq=   864000.,
 dumpFreq=   0.,
 dumpInitAndLast = .false.,
 monitorFreq=0.,
 dumpFreq=   1.,
 monitorFreq=1.,
# restoring time scale of only 12 days = 60/5, because surface
# layer is only 10m as opposed to 50m in the 4x4 deg-run.
#tauThetaClimRelax = 1036800.,
# restoring time scale of only 36 days = 30*6 days/5
#tauSaltClimRelax = 3110400.,
 periodicExternalForcing=.TRUE.,
# these should not have any effect, when exf is used
# still I am not allowed to set them to zero
 externForcingPeriod=2592000.,
 externForcingCycle=31104000.,
 &

# Gridding parameters
 &PARM04
 usingCartesianGrid=.TRUE.,
 usingSphericalPolarGrid=.FALSE.,
 delR= 3*1000.,
 dySpacing=5.e3,
 dxSpacing=5.e3,
 &

# Input datasets
 &PARM05
 bathyFile=      'topog.strait8',
#hydrogThetaFile='lev_t.bin',
#hydrogSaltFile= 'lev_s.bin',
 uVelInitFile= 'u10.init',
 &