[MITgcm-support] The way to accelerate the calculation speed or to expand deltaT of MITgcm

[姊佹湅]

Dear Sir:
        I'm trying to use the MITgcm to run an experiment.To simulate this experiment 
successfully it is necessary to set the grid interval to be very small.Now the number of the horizontal grids is 114*104,and the number of the vertical grids is 139.The minimum interval of the horizontal grids is 5 km ,and the minimum interval of the vertical grids is 10m.And now I find that the maximum deltaT in the data file to keep the model steady is 60s. The minimum time that is needed is 30 years,so the minimum number of timesteps (nTimeSteps in the data file)is 16000000.Now I have used 48 cpu to run the model,and it needs 210 days to finish the calculation.The time is too long!! So can you tell me how to  set the model parameters or modify the model code to  accelerate the calculation speed or to expand deltaT.
Thank You,
With Regards,
Liang 
    Some of the parameters I set are as follow:
    The grids of x and y  are as follow:
    nx=104;
    ny=114;
    dx(1:20)=50;
    dx(21:27)=[40:-5:10];
    dx(28:67)=5;
    dx(68:74)=[10:5:40];
    dx(75:nx)=50;
    dx=dx*1000;
    dy(1:38)=25;
    dy(39:42)=[21:-4:9];
    dy(43:92)=5;
    dy(93:96)=[9:4:21];
    dy(97:ny)=25;
    dy=dy*1000;
    The settings of the data file are as follow:
      &PARM01
  tRef=139*20.,
 sRef=139*35.,
 viscAh=0.,
 viscAhGrid=0.,
 viscC2Leith=0.,
 viscA4=0.,
 useFullLeith=.TRUE.,
 viscC4Leith=2.0,
 viscC4Leithd=2.0,
 viscAz=1.E-3,
 bottomDragLinear=0.E-4,
 bottomDragQuadratic=0.003,
 no_slip_sides=.TRUE.,
 no_slip_bottom=.TRUE.,
 diffK4T=0.E4,
 diffKhT=0.E-2,
 diffKzT=0.E-3,
 diffK4S=0.E4,
 diffKhS=0.E-2,
 diffKzS=0.E-5,
 f0=4.97e-5,
 beta=2.30e-11,
 rhonil=1035.,
 rhoConstFresh=1000.,
 eosType = 'JMD95Z',
 rigidLid=.FALSE.,
 implicitFreeSurface=.TRUE.,
 hFacMin=0.05,
 nonHydrostatic=.TRUE.,
 readBinaryPrec=64,
#- not safe to use globalFiles in multi-processors runs
#globalFiles=.TRUE.,
 tempAdvScheme=33,
 &
# Elliptic solver parameters
 &PARM02
 cg2dMaxIters=300,
 cg2dTargetResidual=1.E-13,
 cg3dMaxIters=20,
 cg3dTargetResidual=1.E-8,
 &
# Time stepping parameters
 &PARM03
 nIter0=0,
 nTimeSteps=16000000,
 deltaT=60.0,
 abEps=0.01,
 pChkptFreq=600000.0,
 chkptFreq=600000.0,
 dumpFreq=6000000.0,
 tauThetaClimRelax=100000.0,
 monitorFreq=60000.,
 &
# Gridding parameters
 &PARM04
 usingCartesianGrid=.TRUE.,
 delXfile='dx.bin',
 delYfile='dy.bin',
 delZ=100,100,100,100,100,100,100,100,100,100,90,80,70,60,50,40,30,20,102*10,20,30,40,50,60,70,80,90,100,100,100,100,100,100,100,100,100,100,100,
 &
# Input datasets
 &PARM05
 bathyFile='topog.slope',
 hydrogThetaFile='T.init',
 surfQfile='Qnet.forcing',
 thetaClimFile='SST.bin',
 diffKrFile='diffK.bin',
 &


      
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