Hello,
I have a tide simulation with FSOBC_REDUCED since SSH_TIDE and UV_TIDE underestimate the tide amplitude.It runs smoothly when I use ssh and uv,however blowup after 12 days at the open boundary use _reduced;it grows to very negtive gradually.I check the topography is not steep with rx0<0.2 except the land is 10m deep.I tried a short time step with no help.
I have tried
fschapman + m2flather / m2reduced ,they blowup at 9hour / 12days at different open boudary.fsclamped does no help.
I have tried SPONGE,only delay the blow time one day or so.
Any suggestion please?
I use Version 333.
CPP defined:
#define UV_ADV
#define UV_COR
#define UV_VIS2
#define UV_QDRAG
#define MIX_S_UV
#undef SOLVE3D
#define NONLIN_EOS
#undef SALINITY
/* Basic numerics options */
#define UV_U3HADVECTION
#define TS_U3HADVECTION
#define TS_C4VADVECTION
#define DJ_GRADPS
#define SPLINES
#define CURVGRID
#define MASKING
#define WESTERN_WALL
#define SPONGE
#define RAMP_TIDES
#define SSH_TIDES
#define ADD_FSOBC
#define FSOBC_REDUCED
#define EAST_FSCLAMPED
#define SOUTH_FSCLAMPED
#define NORTH_FSCLAMPED
/* #define UV_TIDES
#define ADD_M2OBC */
#define EAST_M2REDUCED
#define EAST_TRADIATION
#define SOUTH_M2REDUCED
#define SOUTH_TRADIATION
#define NORTH_M2REDUCED
#define NORTH_TRADIATION
Does FSOBC_REDUCED seem to blowup more easily
-
stone
Re: Does FSOBC_REDUCED seem to blowup more easily
I notice that the South Boundary is where tide propagate out,so I use the radiation BC,and it works only for 2D case;3D case(keep temp=28;salt=34) blowup（the 2nd step) at this boundary again where there is a slightly rough topography-however I used the LP_bathymetry program to smooth this,only find it seems OK
Maximum grid stiffness ratios: rx0 = 2.000000E-01 (Beckmann and Haidvogel)
rx1 = 6.530954E+00 (Haney)
It runs smoothly with non-FSOBC_REDUCED configuration,it seems that FSOBC_REDUCED is much more strick.But I really want this option.
I look through the momentum terms(where blowup happened),ubar_accel and ubar_prsgrd are ~ 1e-3 while other terms are ~ 1e-5or-6. ; And the temp/salt_adv here is also strange ~1e-3,temp/salt_rate ~ 1e-4;
u at bottom is ~7m/s and is ~1m/s at surface.
It seems the the topo still maybe the problem?
NOW I use:
ADD_FSOBC Adding tidal elevation to proccesed OBC data.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ANA_INITIAL Analytical initial conditions.
ANA_SMFLUX Analytical kinematic surface momentum flux.
ANA_STFLUX Analytical kinematic surface temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
CURVGRID Orthogonal curvilinear grid.
DJ_GRADPS Parabolic Splines density Jacobian (Shchepetkin, 2002).
DOUBLE_PRECISION Double precision arithmetic.
EAST_FSCHAPMAN Eastern edge, free-surface, Chapman condition.
EAST_M2REDUCED Eastern edge, 2D momentum, reduced-physics condition.
EAST_M3RADIATION Eastern edge, 3D momentum, radiation condition.
EAST_TRADIATION Eastern edge, tracers, radiation condition.
FSOBC_REDUCED Using free-surface data in reduced physics condtions
GLS_MIXING Generic Length-Scale turbulence closure.
KANTHA_CLAYSON Kantha and Clayson stability function formulation.
MASKING Land/Sea masking.
MIX_GEO_TS Mixing of tracers along geopotential surfaces.
MIX_GEO_UV Mixing of momentum along geopotential surfaces.
MPI MPI distributed-memory configuration.
NONLINEAR Nonlinear Model.
NONLIN_EOS Nonlinear Equation of State for seawater.
NORTH_FSCHAPMAN Northern edge, free-surface, Chapman condition.
NORTH_M2REDUCED Northern edge, 2D momentum, reduced-physics condition.
NORTH_M3RADIATION Northern edge, 3D momentum, radiation condition.
NORTH_TRADIATION Northern edge, tracers, radiation condition.
N2S2_HORAVG Horizontal smoothing of buoyancy and shear.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
K_GSCHEME Third-order upstream advection of TKE fields.
RADIATION_2D Use tangential phase speed in radiation conditions.
RAMP_TIDES Ramping tidal forcing for one day.
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SOLVE3D Solving 3D Primitive Equations.
SOUTH_FSCHAPMAN Southern edge, free-surface, Chapman condition.
SOUTH_M2RADIATION Southern edge, 2D momentum, radiation condition.
SOUTH_M3RADIATION Southern edge, 3D momentum, radiation condition.
SOUTH_TRADIATION Southern edge, tracers, radiation condition.
SPLINES Conservative parabolic spline reconstruction.
SPONGE Enhanced horizontal mixing in the sponge areas.
SSH_TIDES Add tidal elevation to SSH climatology.
STATIONS Writing out station data.
TS_U3HADVECTION Third-order upstream horizontal advection of tracers.
TS_C2VADVECTION Second-order centered 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_LOGDRAG Logarithmic bottom stress.
UV_VIS2 Harmonic mixing of momentum.
VAR_RHO_2D Variable density barotropic mode.
WESTERN_WALL
Can someone help me ?
Thanks
Maximum grid stiffness ratios: rx0 = 2.000000E-01 (Beckmann and Haidvogel)
rx1 = 6.530954E+00 (Haney)
It runs smoothly with non-FSOBC_REDUCED configuration,it seems that FSOBC_REDUCED is much more strick.But I really want this option.
I look through the momentum terms(where blowup happened),ubar_accel and ubar_prsgrd are ~ 1e-3 while other terms are ~ 1e-5or-6. ; And the temp/salt_adv here is also strange ~1e-3,temp/salt_rate ~ 1e-4;
u at bottom is ~7m/s and is ~1m/s at surface.
It seems the the topo still maybe the problem?
NOW I use:
ADD_FSOBC Adding tidal elevation to proccesed OBC data.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ANA_INITIAL Analytical initial conditions.
ANA_SMFLUX Analytical kinematic surface momentum flux.
ANA_STFLUX Analytical kinematic surface temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
CURVGRID Orthogonal curvilinear grid.
DJ_GRADPS Parabolic Splines density Jacobian (Shchepetkin, 2002).
DOUBLE_PRECISION Double precision arithmetic.
EAST_FSCHAPMAN Eastern edge, free-surface, Chapman condition.
EAST_M2REDUCED Eastern edge, 2D momentum, reduced-physics condition.
EAST_M3RADIATION Eastern edge, 3D momentum, radiation condition.
EAST_TRADIATION Eastern edge, tracers, radiation condition.
FSOBC_REDUCED Using free-surface data in reduced physics condtions
GLS_MIXING Generic Length-Scale turbulence closure.
KANTHA_CLAYSON Kantha and Clayson stability function formulation.
MASKING Land/Sea masking.
MIX_GEO_TS Mixing of tracers along geopotential surfaces.
MIX_GEO_UV Mixing of momentum along geopotential surfaces.
MPI MPI distributed-memory configuration.
NONLINEAR Nonlinear Model.
NONLIN_EOS Nonlinear Equation of State for seawater.
NORTH_FSCHAPMAN Northern edge, free-surface, Chapman condition.
NORTH_M2REDUCED Northern edge, 2D momentum, reduced-physics condition.
NORTH_M3RADIATION Northern edge, 3D momentum, radiation condition.
NORTH_TRADIATION Northern edge, tracers, radiation condition.
N2S2_HORAVG Horizontal smoothing of buoyancy and shear.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
K_GSCHEME Third-order upstream advection of TKE fields.
RADIATION_2D Use tangential phase speed in radiation conditions.
RAMP_TIDES Ramping tidal forcing for one day.
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SOLVE3D Solving 3D Primitive Equations.
SOUTH_FSCHAPMAN Southern edge, free-surface, Chapman condition.
SOUTH_M2RADIATION Southern edge, 2D momentum, radiation condition.
SOUTH_M3RADIATION Southern edge, 3D momentum, radiation condition.
SOUTH_TRADIATION Southern edge, tracers, radiation condition.
SPLINES Conservative parabolic spline reconstruction.
SPONGE Enhanced horizontal mixing in the sponge areas.
SSH_TIDES Add tidal elevation to SSH climatology.
STATIONS Writing out station data.
TS_U3HADVECTION Third-order upstream horizontal advection of tracers.
TS_C2VADVECTION Second-order centered 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_LOGDRAG Logarithmic bottom stress.
UV_VIS2 Harmonic mixing of momentum.
VAR_RHO_2D Variable density barotropic mode.
WESTERN_WALL
Can someone help me ?
Thanks
-
stone
Re: Does FSOBC_REDUCED seem to blowup more easily
1)Finally,I find out what makes it blowup(and makes me crazy) is UV_VIS2.
Without this cpp, it runs longer( at least 9 days).I can't understand why?!
2)And it blowup when I use M2reduced at Southern OB, it can run with South_M2radiation just as I mentioned.
I also wonder is it just be fine enough with Open Boundary bathymetry ratio rx0<0.2, Or I need more flat OB bathymetry? And would this affect the interior point's instability?
3)The baroclinic step also affect, I only use constant Tempreture and Salinity.
How would this affect the instability in this case.
Please forgive my ignorance, and give me some guide.
Thanks.
Without this cpp, it runs longer( at least 9 days).I can't understand why?!
2)And it blowup when I use M2reduced at Southern OB, it can run with South_M2radiation just as I mentioned.
I also wonder is it just be fine enough with Open Boundary bathymetry ratio rx0<0.2, Or I need more flat OB bathymetry? And would this affect the interior point's instability?
3)The baroclinic step also affect, I only use constant Tempreture and Salinity.
How would this affect the instability in this case.
Please forgive my ignorance, and give me some guide.
Thanks.
Re: Does FSOBC_REDUCED seem to blowup more easily
If your temperature and salinity are uniform, then you shouldn't be getting pressure gradient errors. Therefore, the bottom steepness should be fine.
Since you are using the U3HADVECTION, you will likely be able to get away without explicit horizontal smoothing - some small amount is built into that advection scheme.
Bathymetric steepness at the boundary: what we usually look for is to have the boundary come into the coast at right angles so that the flow isn't hitting the boundary obliquely.
I have very, very little experience with the reduced boundary conditions, so can't help you there.
Since you are using the U3HADVECTION, you will likely be able to get away without explicit horizontal smoothing - some small amount is built into that advection scheme.
Bathymetric steepness at the boundary: what we usually look for is to have the boundary come into the coast at right angles so that the flow isn't hitting the boundary obliquely.
I have very, very little experience with the reduced boundary conditions, so can't help you there.