I am facing an issue of exceptionally lower velocity than expected values in one of my simulation results. The expected velocities in my simulation should somewhere be in the range of 0.5 to 1 m/s for the timestamp but my outcomes of each individual momentum field variable at a given timestamp and vertical level are always in the order of ( 10^-3, 10^-4) when I try to visualise it in a pcolour MATLAB plot. I am not sure what is happening there. I tried to modify my quadratic bottom roughness coefficient by reducing it but that didn't help my cause as velocities tend to remain in the same order. This is a problem I am facing quite often. I am pretty sure I am doing something horribly wrong.
What might be the underlying reasons for this anomaly? I am using an external grid, tidal and wind forcing and my initial file is ana_initial. Rest all is pretty much standard ROMS provided dependencies.
My header file looks like this :
And my parameters in the .in executable look something like this:#define UV_ADV
#define UV_COR
#define UV_QDRAG
#define UV_VIS4
#define MIX_S_UV
#define DJ_GRADPS
#define SPLINES_VDIFF
#define SPLINES_VVISC
#define BULK_FLUXES
#define SOLVE3D
#define BODYFORCE
#define ANA_SMFLUX
#define ANA_STFLUX
#define ANA_INITIAL
#define ANA_SSFLUX
#define ANA_DRAG
#define ANA_BSFLUX
#define ANA_BTFLUX
#define MASKING
#define SSH_TIDES
#define UV_TIDES
#undef RAMP_TIDES
#define ADD_FSOBC
#define ADD_M2OBC
Are there any possible modifications that I could try in my .in file executable so as to improve my u,v,w momentum values? Or it's a fundamental error in my grid file and forcing files?Resolution, Grid 01: 98x48x15, Parallel Threads: 1, Tiling: 1x1
Physical Parameters, Grid: 01
=============================
6000 ntimes Number of timesteps for 3-D equations.
30.000 dt Timestep size (s) for 3-D equations.
20 ndtfast Number of timesteps for 2-D equations between
each 3D timestep.
1 ERstr Starting ensemble/perturbation run number.
1 ERend Ending ensemble/perturbation run number.
0 nrrec Number of restart records to read from disk.
T LcycleRST Switch to recycle time-records in restart file.
360 nRST Number of timesteps between the writing of data
into restart fields.
360 ninfo Number of timesteps between print of information
to standard output.
T ldefout Switch to create a new output NetCDF file(s).
60 nHIS Number of timesteps between the writing fields
into history file.
0 nQCK Number of timesteps between the writing fields
into quicksave file.
0.0000E+00 nl_visc4 NLM Horizontal, biharmonic mixing coefficient
(m4/s) for momentum.
F LuvSponge Turning OFF sponge on horizontal momentum.
F LtracerSponge(01) Turning OFF sponge on tracer 01: temp
1.0000E-06 Akt_bak(01) Background vertical mixing coefficient (m2/s)
for tracer 01: temp
1.0000E+00 Akv_bak Background vertical mixing coefficient (m2/s)
for momentum.
2.6500E-04 rdrg Linear bottom drag coefficient (m/s).
3.0000E-03 rdrg2 Quadratic bottom drag coefficient.
2.0000E-03 Zob Bottom roughness (m).
1.0000E+01 blk_ZQ Height (m) of surface air humidity measurement.
1.0000E+01 blk_ZT Height (m) of surface air temperature measurement.
1.0000E+01 blk_ZW Height (m) of surface winds measurement.
12 levsfrc Deepest level to apply surface stress as a
bodyforce.
1 levbfrc Shallowest level to apply bottom stress as a
bodyforce.
2 Vtransform S-coordinate transformation equation.
4 Vstretching S-coordinate stretching function.
8.0000E+00 theta_s S-coordinate surface control parameter.
4.0000E+00 theta_b S-coordinate bottom control parameter.
20.000 Tcline S-coordinate surface/bottom layer width (m) used
in vertical coordinate stretching.
1025.000 rho0 Mean density (kg/m3) for Boussinesq approximation.
2922.000 dstart Time-stamp assigned to model initialization (days).
2922.000 tide_start Reference time origin for tidal forcing (days).
20000101.00 time_ref Reference time for units attribute (yyyymmdd.dd)
5.0000E+01 Tnudg(01) Nudging/relaxation time scale (days)
for tracer 01: temp
0.0000E+00 Znudg Nudging/relaxation time scale (days)
for free-surface.
0.0000E+00 M2nudg Nudging/relaxation time scale (days)
for 2D momentum.
0.0000E+00 M3nudg Nudging/relaxation time scale (days)
for 3D momentum.
0.0000E+00 obcfac Factor between passive and active
open boundary conditions.
F VolCons(1) NLM western edge boundary volume conservation.
F VolCons(2) NLM southern edge boundary volume conservation.
F VolCons(3) NLM eastern edge boundary volume conservation.
F VolCons(4) NLM northern edge boundary volume conservation.
5.000 T0 Background potential temperature (C) constant.
35.000 S0 Background salinity (PSU) constant.
1028.000 R0 Background density (kg/m3) used in linear Equation
of State.
1.0000E-04 Tcoef Thermal expansion coefficient (1/Celsius).
0.0000E+00 Scoef Saline contraction coefficient (1/PSU).
1.000 gamma2 Slipperiness variable: free-slip (1.0) or
no-slip (-1.0).
F LuvSrc Turning OFF momentum point Sources/Sinks.
F LwSrc Turning OFF volume influx point Sources/Sinks.
F LtracerSrc(01) Turning OFF point Sources/Sinks on tracer 01: temp
F LsshCLM Turning OFF processing of SSH climatology.
F Lm2CLM Turning OFF processing of 2D momentum climatology.
F Lm3CLM Turning OFF processing of 3D momentum climatology.
F LtracerCLM(01) Turning OFF processing of climatology tracer 01: temp
F LnudgeM2CLM Turning OFF nudging of 2D momentum climatology.
F LnudgeM3CLM Turning OFF nudging of 3D momentum climatology.
F LnudgeTCLM(01) Turning OFF nudging of climatology tracer 01: temp
T Hout(idFsur) Write out free-surface.
T Hout(idUbar) Write out 2D U-momentum component.
T Hout(idVbar) Write out 2D V-momentum component.
T Hout(idUvel) Write out 3D U-momentum component.
T Hout(idVvel) Write out 3D V-momentum component.
T Hout(idWvel) Write out W-momentum component.
T Hout(idOvel) Write out omega vertical velocity.
T Hout(idTvar) Write out tracer 01: temp
T Hout(idUsms) Write out surface U-momentum stress.
T Hout(idVsms) Write out surface V-momentum stress.
T Hout(idUbms) Write out bottom U-momentum stress.
T Hout(idVbms) Write out bottom V-momentum stress.
T Hout(idPair) Write out surface air pressure.
T Hout(idTair) Write out surface air temperature.
T Hout(idUair) Write out surface U-wind component.
T Hout(idVair) Write out surface V-wind component.
T Hout(idDano) Write out density anomaly.
Output/Input Files:
Kind regards
-Neel
