Configurations of Climatological simulation

[zhouwei]

Hello All!

I want to setup my first application by using climatological forcings(ECMWF wind and COADS heat flux) and boundary conditions(SODA). My physical and numerical settings are as follows:

Activated C-preprocessing Options:

SCS South China sea ERA wind
ANA_BSFLUX Analytical kinematic bottom salinity flux.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
AVERAGES Writing out time-averaged fields.
AVERAGES_FLUXES Writing out time-averaged surface fluxes.
CURVGRID Orthogonal curvilinear grid.
DIAGNOSTICS_TS Computing and writing tracer diagnostic terms.
DIAGNOSTICS_UV Computing and writing momentum diagnostic terms.
DJ_GRADPS Parabolic Splines density Jacobian (Shchepetkin, 2002).
DOUBLE_PRECISION Double precision arithmetic.
EAST_FSGRADIENT Eastern edge, free-surface, gradient condition.
EAST_M2NUDGING Eastern edge, 2D momentum, passive/active outflow/inflow.
EAST_M2RADIATION Eastern edge, 2D momentum, radiation condition.
EAST_M3NUDGING Eastern edge, 3D momentum, passive/active outflow/inflow.
EAST_M3RADIATION Eastern edge, 3D momentum, radiation condition.
EAST_TNUDGING Eastern edge, tracers, passive/active outflow/inflow.
EAST_TRADIATION Eastern edge, tracers, radiation condition.
EAST_VOLCONS Eastern edge, enforce mass conservation.
KANTHA_CLAYSON Kantha and Clayson stability function formulation.
MASKING Land/Sea masking.
MIX_GEO_TS Mixing of tracers along geopotential surfaces.
MIX_S_UV Mixing of momentum along constant S-surfaces.
MPI MPI distributed-memory configuration.
MY25_MIXING Mellor/Yamada Level-2.5 mixing closure.
NONLINEAR Nonlinear Model.
NONLIN_EOS Nonlinear Equation of State for seawater.
NORTHERN_WALL Wall boundary at Northern edge.
N2S2_HORAVG Horizontal smoothing of buoyancy and shear.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
QCORRECTION Surface net heat flux correction.
K_GSCHEME Third-order upstream advection of TKE fields.
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SCORRECTION Surface salinity flux correction.
SOLVE3D Solving 3D Primitive Equations.
SOUTH_FSGRADIENT Southern edge, free-surface, gradient condition.
SOUTH_M2NUDGING Southern edge, 2D momentum, passive/active outflow/inflow.
SOUTH_M2RADIATION Southern edge, 2D momentum, radiation condition.
SOUTH_M3NUDGING Southern edge, 3D momentum, passive/active outflow/inflow.
SOUTH_M3RADIATION Southern edge, 3D momentum, radiation condition.
SOUTH_TNUDGING Southern edge, tracers, passive/active outflow/inflow.
SOUTH_TRADIATION Southern edge, tracers, radiation condition.
SOUTH_VOLCONS Southern edge, enforce mass conservation.
SPLINES Conservative parabolic spline reconstruction.
TS_U3HADVECTION Third-order upstream horizontal advection of tracers.
TS_SVADVECTION Parabolic splines vertical advection of tracers.
TS_DIF2 Harmonic mixing of tracers.
UV_ADV Advection of momentum.
UV_COR Coriolis term.
UV_U3HADVECTION Third-order upstream horizontal advection of 3D momentum.
UV_C4VADVECTION Fourth-order centered vertical advection of momentum.
UV_QDRAG Quadratic bottom stress.
UV_VIS2 Harmonic mixing of momentum.
VAR_RHO_2D Variable density barotropic mode.
WESTERN_WALL Wall boundary at Western edge.

I spin up the model for ten years,but I find there are some problems of results. I present the 50m layer's summer-averaged temp and horizontal velocity in the picture.

1, There is obvious temperature gradient near the east and south open boundanry. But I don't know why. Is it caused by the inappropriate CPP settings ?
2, The circulation is not reasonable ,especially for Kuroshio current.

My questions : Are there popular CPP settings for climatological run?.Or there are unreasonable CPPs for my settings?
Is there something wrong with the the value of parameters in the file log1.txt

Thanks for your help.

[feroda]

Hi Wei,

Beautiful works!
I just looked through your log file. Personally, some parameters there are worthwhile to be double checked.

300.000 dt Timestep size (s) for 3-D equations.
10 ndtfast Number of timesteps for 2-D equations between
each 3D timestep.
7200 nHIS Number of timesteps between the writing fields
into history file.
8640 nAVG Number of timesteps between the writing of
time-averaged data into averages file.
That means you write your results every 25 and 30 days into history and average files, respectively. Even thought you just want to look at the climatological pattern, you will definitely miss a lot of stories from your history files.

2.5000E+00 theta_s S-coordinate surface control parameter.
8.0000E-01 theta_b S-coordinate bottom control parameter.
5.000 Tcline S-coordinate surface/bottom layer width (m) used
in vertical coordinate stretching.
To my knowledge, that means your minimum water depth is 5m(?), while theta_s is valued with 2.5 which doesn't seem reasonable to me. You know, the maximum water depth in your domain is around 10000m, and your vertical grid levels are mainly refined in the bottom. So, It is hard to capture the surface dynamics of the SCS. I think that's why you got much more warm water in the center basin than that in the SSCS. Please double check your vertical levels by plotting them out.

Furthermore, I do not think the GRADIENT option for east OB is the best choice. If you plot out the FS along east OB,you can see the HUGE SSH gradient there, which means it is necessary for the model to get this information from your boundary input file. However, that can not be done by using of GRADIENT.
Probably, that's why you can not get the strong west boundary currents both east coast of Vietnam and the SSCS, nor for the area close to your east OB. That may also the reason for T/S gradient along east and south OBs. Try FSCHAPMAN and M2FLATHER instead.

Good Luck.

Dakui

[yang]

I have two question about your configuration?
1. Can we use both M2RADIATION and M2NUDGING options together for 2D momentum in east open boundary??
#define EAST_M2RADIATION
#define EAST_M2NUDGING
I have not seen such configuratin in all of the *.h in "ROMS\Include\" .
2. How did you run the Climatology simulation ? Run the simulation ten year in only one time or ten times restarted from every year's *rst.nc?

[zhouwei]

Thank you so much for your help, Dakui. I will try it following your kindly suggestions and then present the new result as soon as possible.

Hi,yang. I can only answer your second question as I have few experience of modelling,especially of ROMS.

2. How did you run the Climatology simulation ? Run the simulation ten year in only one time or ten times restarted from every year's *rst.nc?

I run the model for ten years in one time by adding 'cycle_length' in the frc and bry nc files.