Boundary Zeta Instability

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kehinson
Posts: 5
Joined: Fri Dec 08, 2017 6:35 pm
Location: PNNL

Boundary Zeta Instability

#1 Unread post by kehinson »

Hi all. I'm working on setting up a ROMS application using a lambert conformal grid projection that I created with pygridgen, but am finding some strange behavior at the open boundaries with respect to sea surface height (below). Using essentially the same setup, I don't run into this error when using a grid with a regular lat/lon projection. My input files (boundary, initial, climatology) are based on HYCOM data interpolated to the ROMS grid.
zeta boundary v2.jpg
Essentially, a wave immediately (within a minute or less) begins to propagate and expand from the boundaries to the coastline over time. I can still run ROMS for a good amount of time despite this behavior, but I'm also trying to run it within the COAWST system. There I find that it causes the coupled system to crash at the first time step when information is exchanged between WRF and ROMS.

One place where I thought that there may be an error was in the angle values of the grid file. But, as shown below, they are relatively small and now I'm not so sure that they're the cause of this zeta boundary error. Thanks for any tips about where I might have gone wrong with my model setup, I appreciate the help!
angle plot v2.jpg
angle plot v2.jpg (146.32 KiB) Viewed 6280 times
__________________________________________________________________________
I've also included below the output from my header file if it's useful.

/*
** svn $Id: estuary_test.h 429 2009-12-20 17:30:26Z arango $
*******************************************************************************
** Copyright (c) 2002-2010 The ROMS/TOMS Group **
** Licensed under a MIT/X style license **
** See License_ROMS.txt **
*******************************************************************************
**
** Options for Estuary test.
**
** Application flag: ESTUARY_TEST2
** Input script: ocean_estuary_test2.in
*/

#define ROMS_MODEL

/* ROMS OPTIONS */
#define SALINITY
#define NONLIN_EOS
#define SOLVE3D
#define SPLINES_VVISC
#define SPLINES_VDIFF

#define DJ_GRADPS
#define CURVGRID

#define UV_ADV
#define UV_COR
#define UV_VIS2
#define MIX_S_UV
#define MIX_S_TS
#define TS_DIF2 /* Harmoic horizontal mixing of tracers */

/* Bottom Boundary Conditions */
#define UV_QDRAG

/* Turbulence Closure */
#define GLS_MIXING
#define LIMIT_VDIFF
#define LIMIT_VVISC
#if defined GLS_MIXING
# define KANTHA_CLAYSON
# define N2S2_HORAVG
# define RI_SPLINES
#endif

#define MASKING

/* Undefine if starting from a file */
#undef ANA_INITIAL

/* Surface Forcing */
#define BULK_FLUXES /* Adapatation of COARE Fairall et al. 1996) */
#ifdef BULK_FLUXES
# define EMINUSP /* Evaporation and Precipitation */
# define ATM_PRESS /* Sea level pressure (inverse barometer) */
# define LONGWAVE_OUT /* Compute upward lwrad from SST (needs lwrad_down) */
# undef LONGWAVE /* Needs cloud */
# define SOLAR_SOURCE /* Activate if the net shortwave radiation needs to penetrate layers */
# undef COOL_SKIN /* Correction if you input downward (not net) short wave radiation */
# undef DIURNAL_SRFLUX /* use to impose shortwave radiation local diurnal cycle */
#else
# define ANA_SMFLUX
# define ANA_STFLUX
# define ANA_SSFLUX
# define ANA_SPFLUX
# define ANA_SRFLUX /* Analytical surface shortwave radiation flux */
#endif

/* Bottom Layer*/
#define ANA_BTFLUX
#define ANA_BSFLUX
#define ANA_BPFLUX

/* Open Boundary Conditions*/
#undef ANA_FSOBC /* Free surface Open Boundary Condition */
#undef ANA_M2OBC /* 2D Momentum Open Boundary Condition */
#undef ANA_TOBC /* Analytical tracer open boundary conditions */

/* Tides */
#undef ADD_FSOBC /* use to add tidal elevations to procssed OBC data */
#undef ADD_M2OBC /* use to add tidal currents to processed OBC data */
#undef SSH_TIDES /* use if imposing tidal elevation */
#undef UV_TIDES /* use if imposing tidal currents */
#undef RAMP_TIDES /* use if ramping tidal forcing */

/* Output */
#undef STATIONS /* Extract station output */

jcwarner
Posts: 1200
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: Boundary Zeta Instability

#2 Unread post by jcwarner »

look at the temp and salt, they might be contributing.
what did you set for the bc's in the ocean.in file.

kehinson
Posts: 5
Joined: Fri Dec 08, 2017 6:35 pm
Location: PNNL

Re: Boundary Zeta Instability

#3 Unread post by kehinson »

Thanks John. Temperature and salinity look okay to me, below are surface plots and western boundary profile views of both at the starting time step. The next time step is also basically identical.
surface plots v2.jpg
w bry plots v2.jpg
The boundary conditions that I've set are below. I also tried running a bathtub case by closing all of the BCs but ran into the same issue.

! W S E N
! e o a o
! s u s r
! t t t t
! h h
!
! 1 2 3 4

LBC(isFsur) == Cha Cha Clo Cha ! free-surface
LBC(isUbar) == Fla Fla Clo Fla ! 2D U-momentum
LBC(isVbar) == Fla Fla Clo Fla ! 2D V-momentum
LBC(isUvel) == RadNud RadNud Clo RadNud ! 3D U-momentum
LBC(isVvel) == RadNud RadNud Clo RadNud ! 3D V-momentum
LBC(isMtke) == Gra Gra Clo Gra ! mixing TKE

LBC(isTvar) == RadNud RadNud Clo RadNud \ ! temperature
RadNud RadNud Clo RadNud ! salinity

! Wec boundary conditions

LBC(isU2Sd) == Gra Gra Clo Gra ! 2D U-stokes
LBC(isV2Sd) == Gra Gra Clo Gra ! 2D V-stokes
LBC(isU3Sd) == Gra Gra Clo Gra ! 3D U-stokes
LBC(isV3Sd) == Gra Gra Clo Gra ! 3D V-stokes

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