[MITgcm-support] Potentially unstable time-stepping

Daniel Iván Garduño Ruíz dan_y at ciencias.unam.mx
Tue Oct 6 22:37:36 EDT 2015 

Hi,

in order to make a simulation of a gravity current and compare it with a
laboratory experiment I've been trying to run the plume on a slope
experiment with a scale one thousand times smaller than the original
(Lx=6.4, H=0.2). I've made the necessary changes in the parameters of the
topography in the gendata.m file with the purpose of adjust it to the new
domain and I reduced the cooling function by a factor of 1000 (Qo=0.2) .
I've also reduced one thousand times the time step (deltaT=2.E-2) in the
data file to meet the CLF condition. However, when I run the code during
20s (nTimeSteps=1000) obtaining data each second ( dumpFreq=1) the output
is always zero except for the initial condition. Below I copied one section
of the output in the terminal. It says that the time step is potentially
unstable.

Should I reduce even more the time steep or how could I solve this problem?

Thanks,

Daniel.


** WARNING ** GAD_CHECK: potentially unstable time-stepping (Internal Wave)

** WARNING ** GAD_CHECK: need "staggerTimeStep=.TRUE." in "data", nml
PARM01

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // Check Model config. (CONFIG_CHECK):

(PID.TID 0000.0001) // CONFIG_CHECK : Normal End

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001)

(PID.TID 0000.0001) MDS_READ_FIELD: opening global file: T.init

(PID.TID 0000.0001) Start initial hydrostatic pressure computation

(PID.TID 0000.0001) Pressure is predetermined for buoyancyRelation OCEANIC

(PID.TID 0000.0001)

(PID.TID 0000.0001) MDS_READ_FIELD: opening global file: Qnet.forcing

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // Model current state

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001)

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // Begin MONITOR dynamic field statistics

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) %MON time_tsnumber = 0

(PID.TID 0000.0001) %MON time_secondsf = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_eta_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_eta_min = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_eta_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_eta_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_eta_del2 = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_uvel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_uvel_min = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_uvel_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_uvel_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_uvel_del2 = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_vvel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_vvel_min = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_vvel_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_vvel_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_vvel_del2 = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_wvel_max = -0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_wvel_min = -0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_wvel_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_wvel_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_wvel_del2 = 0.0000000000000E+00

(PID.TID 0000.0001) %MON dynstat_theta_max = 9.9997277179370E-03

(PID.TID 0000.0001) %MON dynstat_theta_min = 1.1007341536251E-07

(PID.TID 0000.0001) %MON dynstat_theta_mean = 4.9748238137022E-03

(PID.TID 0000.0001) %MON dynstat_theta_sd = 2.8914366758962E-03

(PID.TID 0000.0001) %MON dynstat_theta_del2 = 6.1778061612085E-05

(PID.TID 0000.0001) %MON dynstat_salt_max = 3.5000000000000E+01

(PID.TID 0000.0001) %MON dynstat_salt_min = 3.5000000000000E+01

(PID.TID 0000.0001) %MON dynstat_salt_mean = 3.5000000000000E+01

(PID.TID 0000.0001) %MON dynstat_salt_sd = 1.4210854715202E-14

(PID.TID 0000.0001) %MON dynstat_salt_del2 = 0.0000000000000E+00

(PID.TID 0000.0001) %MON advcfl_uvel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON advcfl_vvel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON advcfl_wvel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON advcfl_W_hf_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON pe_b_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON ke_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON ke_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON ke_vol = 2.0102767852146E-01

(PID.TID 0000.0001) %MON vort_r_min = 0.0000000000000E+00

(PID.TID 0000.0001) %MON vort_r_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON vort_a_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON vort_a_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON vort_p_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON vort_p_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON surfExpan_theta_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON surfExpan_salt_mean = 0.0000000000000E+00

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // End MONITOR dynamic field statistics

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // Begin OBCS MONITOR field statistics

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) %MON obc_time_tsnumber = 0

(PID.TID 0000.0001) %MON obc_time_secondsf = 0.0000000000000E+00

(PID.TID 0000.0001) %MON obc_E_uVel_max = 0.0000000000000E+00

(PID.TID 0000.0001) %MON obc_E_uVel_min = 0.0000000000000E+00

(PID.TID 0000.0001) %MON obc_E_uVel_mean = 0.0000000000000E+00

(PID.TID 0000.0001) %MON obc_E_uVel_sd = 0.0000000000000E+00

(PID.TID 0000.0001) %MON obc_E_uVel_Int = 0.0000000000000E+00

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) // End OBCS MONITOR field statistics

(PID.TID 0000.0001) //
=======================================================

(PID.TID 0000.0001) SOLVE_FOR_PRESSURE: putPmEinXvector = F

(PID.TID 0000.0001) SOLVE_FOR_PRESSURE: zeroPsNH= F , zeroMeanPnh= F

(PID.TID 0000.0001) SOLVE_FOR_PRESSURE: oldFreeSurfTerm = T

cg2d: Sum(rhs),rhsMax = -1.11022302462516E-15 4.16208189655871E-07

cg3d: Sum(rhs),rhsMax = 1.13880909910491E-13 6.48786798521496E-08

cg2d: Sum(rhs),rhsMax = 1.43684958260337E-04 4.09672560404331E-07

cg3d: Sum(rhs),rhsMax = 5.64151156345893E-13 6.58423611597169E-08

cg2d: Sum(rhs),rhsMax = -4.02391724786677E-06 8.32099177935017E-07

cg3d: Sum(rhs),rhsMax = 2.16649614914743E-14 9.86155752812277E-07

cg2d: Sum(rhs),rhsMax = 7.15636038950301E-05 1.04243044253794E-04

cg3d: Sum(rhs),rhsMax = 3.28719256675880E-14 1.54873177128291E-04

cg2d: Sum(rhs),rhsMax = -5.99399655902970E-05 1.90388017625743E-02

cg3d: Sum(rhs),rhsMax = -3.79868798092500E-14 2.82514076588151E-02

cg2d: Sum(rhs),rhsMax = 5.05327454504265E-05 3.94687573206943E+00

cg3d: Sum(rhs),rhsMax = 1.07722613618686E-14 5.65801409291792E+00

cg2d: Sum(rhs),rhsMax = -1.78674737723434E-06 1.43411501340701E+04

cg3d: Sum(rhs),rhsMax = -2.07628867749730E-14 1.54961559371665E+04

cg2d: Sum(rhs),rhsMax = 1.13194488982581E-08 3.32174372472093E+10

cg3d: Sum(rhs),rhsMax = 5.54231974962240E-15 2.85084780469162E+10

cg2d: Sum(rhs),rhsMax = -1.13410996449112E-15 8.23101580641206E+22

cg3d: Sum(rhs),rhsMax = -5.40324792602136E-14 1.27380228128126E+23

cg2d: Sum(rhs),rhsMax = -6.12539551846340E-16 2.15786321285662E+47

cg3d: Sum(rhs),rhsMax = -2.10556433944292E-14 4.51157439515894E+47

cg2d: Sum(rhs),rhsMax = -8.05295438826218E-16 4.33667236140372E+95

cg3d: Sum(rhs),rhsMax = -1.74479175477926E-14 2.35281615543187E+96

cg2d: Sum(rhs),rhsMax = -3.36390730847025E-16 1.75635788606602+193

cg3d: Sum(rhs),rhsMax = -5.57545801979570E-14 2.19009354157428+193

cg2d: Sum(rhs),rhsMax = NaN Infinity

cg3d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00

cg2d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00

cg3d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00

cg2d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00

cg3d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00

cg2d: Sum(rhs),rhsMax = NaN 0.00000000000000E+00
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