looks like some problems at the coastline corners

[ocean011]

Hi,i am running a project about north atalantic,and the model is blowing up,i checked the result and found that it's looks like some problems at the coastline corners ,grid size is 1/12degree * 1/12degree,time steps is 180seconds,here is the surface u velocity component at each time step and the cpp options,could anyone help me?Thanks you all in advance.
cpp options:
ANA_BSFLUX Analytical kinematic bottom salinity flux.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ANA_SSFLUX Analytical kinematic surface salinity flux.
ANA_STFLUX Analytical kinematic surface temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
AVERAGES Writing out time-averaged fields.
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.
LMD_CONVEC LMD convective mixing due to shear instability.
LMD_MIXING Large/McWilliams/Doney interior mixing.
LMD_NONLOCAL LMD convective nonlocal transport.
LMD_RIMIX LMD diffusivity due to shear instability.
LMD_SKPP KPP surface boundary layer mixing.
MASKING Land/Sea masking.
MIX_S_TS Mixing of tracers along constant S-surfaces.
MPI MPI distributed-memory configuration.
NONLINEAR Nonlinear Model.
NONLIN_EOS Nonlinear Equation of State for seawater.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SOLVE3D Solving 3D Primitive Equations.
SPLINES Conservative parabolic spline reconstruction.
TS_U3HADVECTION Third-order upstream horizontal advection of tracers.
TS_C4VADVECTION Fourth-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_QDRAG Quadratic bottom stress.
VAR_RHO_2D Variable density barotropic mode.
WET_DRY Wetting and drying activated.

[kate]

Which way is your u-velocity? If positive u is to the east, then you have strong downwelling flow in a very narrow band. It doesn't really make sense, oceanographically. What is driving that flow? Where does the water go? You have massive divergent flow so there must be some powerful forces causing it.

[tony1230]

hi kate, why would you say"If positive u is to the east, then you have strong downwelling flow in a very narrow band." i wanna know how you identified the "downwelling flow"! thank you !

[kate]

It just means you have surface flow towards the coast. It can't go into the coast so must go down. But yours doesn't make it to the coast - if it is indeed what that plot represents.

[ocean011]

Which way is your u-velocity? If positive u is to the east, then you have strong downwelling flow in a very narrow band. It doesn't really make sense, oceanographically. What is driving that flow? Where does the water go? You have massive divergent flow so there must be some powerful forces causing it.

Hi,Kate.The postive u is the eastward velocity component.I checked the initial field,and calculated the du/dx+dv/dy to vertify the convergency and divergency.They are likely to result in the unstable state. Thank you very much for your help.