I am running a nested simulation. It have 3 child grids for 3 channels with a resolution about 10 meters. The channels are quite narrow (50/70 m width) and shallow (5 meters). I have used different vertical mixing schemes: MY25, GLS and LMD. If I use GLS or LMD my model is very stable but I get low current velocities compared to the one measured by the ADCP deployed in the area but if I use MY25 my velocities are more realistic but my model get unstable. I have been doing different test but I always get the same results (MY25 more realistic but unstable). I will really appreciated any help or suggestion.

Thanks a lot.

My configuration used are :

*#define STATIONS*

#undef FLOATS

#undef DIAGNOSTICS_UV

#define MASKING

#define SOLVE3D

#undef ONE_WAY

#define UV_ADV

#define UV_COR

#define UV_VIS2

#define UV_QDRAG

#define DJ_GRADPS

#define CURVGRID

#define MIX_S_UV

#define TS_U3HADVECTION

#define TS_C4VADVECTION

#define SALINITY

#define NONLIN_EOS

#define MY25_MIXING

# ifdef MY25_MIXING

# undef N2S2_HORAVG

# define KANTHA_CLAYSON

# undef UV_LOGDRAG

# define K_C2ADVECTION

# undef K_C4ADVECTION

# endif

#undef GLS_MIXING

#if defined GLS_MIXING

# define KANTHA_CLAYSON

# define N2S2_HORAVG

# define CRAIG_BANNER

# define CHARNOK

# undef ZOS_HSIG

# undef TKE_WAVEDISS

#endif

#undef LMD_MIXING

#ifdef LMD_MIXING

# define LMD_CONVEC

#define LMD_DDMIX

# define LMD_SKPP

# define LMD_BKPP

# define LMD_NONLOCAL

# define LMD_RIMIX

#endif

#define ANA_BTFLUX

#define ANA_BSFLUX

#define SSH_TIDES

#define UV_TIDES

#define ADD_FSOBC

#define ADD_M2OBC

#define BULK_FLUXES

#ifdef BULK_FLUXES

# define CLOUDS

# define ALBEDO

# define DIURNAL_SRFLUX

# define LONGWAVE

# define ANA_RAIN

# undef ANA_PAIR

# define ANA_CLOUD

# define ANA_SST

# undef ANA_TAIR

# undef ANA_HUMID

# define EMINUSP

#endif

# undef ANA_DRAG

# define UV_DRAG_GRID

#undef FLOATS

#undef DIAGNOSTICS_UV

#define MASKING

#define SOLVE3D

#undef ONE_WAY

#define UV_ADV

#define UV_COR

#define UV_VIS2

#define UV_QDRAG

#define DJ_GRADPS

#define CURVGRID

#define MIX_S_UV

#define TS_U3HADVECTION

#define TS_C4VADVECTION

#define SALINITY

#define NONLIN_EOS

#define MY25_MIXING

# ifdef MY25_MIXING

# undef N2S2_HORAVG

# define KANTHA_CLAYSON

# undef UV_LOGDRAG

# define K_C2ADVECTION

# undef K_C4ADVECTION

# endif

#undef GLS_MIXING

#if defined GLS_MIXING

# define KANTHA_CLAYSON

# define N2S2_HORAVG

# define CRAIG_BANNER

# define CHARNOK

# undef ZOS_HSIG

# undef TKE_WAVEDISS

#endif

#undef LMD_MIXING

#ifdef LMD_MIXING

# define LMD_CONVEC

#define LMD_DDMIX

# define LMD_SKPP

# define LMD_BKPP

# define LMD_NONLOCAL

# define LMD_RIMIX

#endif

#define ANA_BTFLUX

#define ANA_BSFLUX

#define SSH_TIDES

#define UV_TIDES

#define ADD_FSOBC

#define ADD_M2OBC

#define BULK_FLUXES

#ifdef BULK_FLUXES

# define CLOUDS

# define ALBEDO

# define DIURNAL_SRFLUX

# define LONGWAVE

# define ANA_RAIN

# undef ANA_PAIR

# define ANA_CLOUD

# define ANA_SST

# undef ANA_TAIR

# undef ANA_HUMID

# define EMINUSP

#endif

# undef ANA_DRAG

# define UV_DRAG_GRID

Initial file:

! Model iteration loops parameters.

ERstr = 1

ERend = 1

Nouter = 1

Ninner = 1

Nintervals = 1

! Number of eigenvalues (NEV) and eigenvectors (NCV) to compute for the

! Lanczos/Arnoldi problem in the Generalized Stability Theory (GST)

! analysis. NCV must be greater than NEV (see documentation below).

NEV = 2 ! Number of eigenvalues

NCV = 10 ! Number of eigenvectors

LcycleTLM == F

NTLM == 72

NDEFTLM == 0

LcycleADJ == F

NADJ == 72

NDEFADJ == 0

LrstGST = F ! GST restart switch

MaxIterGST = 500 ! maximun number of iterations

NGST = 10 ! check pointing interval

Ritz_tol = 1.0d-15

TNU2 == 2*0.0d0 2*0.0d0 2*0.0d0 2*0.0d0 ! m2/s

TNU4 == 2*0.0d0 2*0.0d0 2*0.0d0 2*0.0d0 ! m4/s

VISC2 == 4*0.001d0 ! m2/s

VISC4 == 4*0.0d0 ! m4/s

AKT_BAK == 4*1.0d-6 4*5.0d-6 ! m2/s

AKV_BAK == 4*1.0d-2 4*1.0d-2 ! m2/s

AKK_BAK == 4*5.0d-6 ! m2/s

AKP_BAK == 4*5.0d-6 ! m2/s

TKENU2 == 4*0.0d0 ! m2/s

TKENU4 == 4*0.0d0 ! m4/s

GLS_P == 4*3.0d0 ! K-epsilon

GLS_M == 4*1.5d0

GLS_N == 4*-1.0d0

GLS_Kmin == 4*7.6d-6

GLS_Pmin == 4*1.0d-12

GLS_CMU0 == 4*0.5477d0

GLS_C1 == 4*1.44d0

GLS_C2 == 4*1.92d0

GLS_C3M == 4*-0.4d0

GLS_C3P == 4*1.0d0

GLS_SIGK == 4*1.0d0

GLS_SIGP == 4*1.30d0

RDRG == 4*3.0d-04 ! m/s

RDRG2 == 4*0.003d0 ! nondimensional

Zob == 4*0.0d0 ! m

Zos == 4*00.0d0 ! m

BLK_ZQ == 4*10.0d0 ! air humidity

BLK_ZT == 4*10.0d0 ! air temperature

BLK_ZW == 4*5.0d0 ! winds

DCRIT == 4*0.10d0 ! m

WTYPE == 4*1

LEVSFRC == 4*15

LEVBFRC == 4*1

Vtransform == 4*2 ! transformation equation

Vstretching == 4*3 ! stretching function

THETA_S == 4*7.0d0 ! surface stretching parameter

THETA_B == 4*0.8d0 ! bottom stretching parameter

TCLINE == 4*4.0d0 ! critical depth (m)

RHO0 = 1026.0d0 ! kg/m3

BVF_BAK = 1.0d-5 ! 1/s2

DSTART = 15622 ! days

TIDE_START = 0.0d0 ! days

TIME_REF = 19680523.00 ! yyyymmdd.dd

! TIME_REF = 00010101.00 ! yyyymmdd.dd

! TNUDG == 4*0.0d0 ! days

! ZNUDG == 4*0.01d0 ! days

! M2NUDG == 4*0.01d0 ! days

! M3NUDG == 4*0.01d0 ! days

! OBCFAC == 1.0d0 ! nondimensional

LBC(isFsur) == Clo Gra RadNud RadNud \ ! free-surface, Grid 1

Nes Nes Nes Nes \ ! free-surface, Grid 2

Nes Nes Nes Nes \ ! free-surface, Grid 3

Nes Nes Nes Nes ! free-surface, Grid 4

LBC(isUbar) == Clo FLa Fla Fla \ ! 2D U-momentum, Grid 1

Nes Nes Nes Nes \ ! 2D U-momentum, Grid 2

Nes Nes Nes Nes \ ! 2D U-momentum, Grid 3

Nes Nes Nes Nes ! 2D U-momentum, Grid 4

LBC(isVbar) == Clo FLa Fla Fla \ ! 2D V-momentum, Grid 1

Nes Nes Nes Nes \ ! 2D V-momentum, Grid 2

Nes Nes Nes Nes \ ! 2D V-momentum, Grid 3

Nes Nes Nes Nes ! 2D V-momentum, Grid 4

LBC(isUvel) == Clo Rad Rad Rad \ ! 3D U-momentum, Grid 1

Nes Nes Nes Nes \ ! 3D U-momentum, Grid 2

Nes Nes Nes Nes \ ! 3D U-momentum, Grid 3

Nes Nes Nes Nes ! 3D U-momentum, Grid 4

LBC(isVvel) == Clo Rad Rad Rad \ ! 3D V-momentum, Grid 1

Nes Nes Nes Nes \ ! 3D V-momentum, Grid 2

Nes Nes Nes Nes \ ! 3D V-momentum, Grid 3

Nes Nes Nes Nes ! 3D V-momentum, Grid 4

LBC(isMtke) == Clo Rad Rad Rad \ ! mixing TKE, Grid 1

Nes Nes Nes Nes \ ! mixing TKE, Grid 2

Nes Nes Nes Nes \ ! mixing TKE, Grid 3

Nes Nes Nes Nes ! mixing TKE, Grid 4

LBC(isTvar) == Clo Gra Gra Gra \ ! temperature, Grid 1

Clo Gra Gra Gra \ ! salinity, Grid 1

Nes Nes Nes Nes \ ! temperature, Grid 2

Nes Nes Nes Nes \ ! salinity, Grid 2

Nes Nes Nes Nes \ ! temperature, Grid 3

Nes Nes Nes Nes \ ! salinity, Grid 3

Nes Nes Nes Nes \ ! temperature, Grid 4

Nes Nes Nes Nes ! salinity, Grid 4

! Linear equation of State parameters:

R0 == 4*1026.0d0 ! kg/m3

T0 == 4*17.0d0 ! Celsius

S0 == 4*37.0d0 ! nondimensional

TCOEF == 4*1.7d-4 ! 1/Celsius

SCOEF == 4*7.6d-4

! Slipperiness parameter: 1.0 (free slip) or -1.0 (no slip)

GAMMA2 == 4*1.0d0

! Starting (DstrS) and ending (DendS) day for adjoint sensitivity forcing.

! DstrS must be less or equal to DendS. If both values are zero, their

! values are reset internally to the full range of the adjoint integration.

DstrS == 0.0d0 ! starting day

DendS == 0.0d0

! Model iteration loops parameters.

ERstr = 1

ERend = 1

Nouter = 1

Ninner = 1

Nintervals = 1

! Number of eigenvalues (NEV) and eigenvectors (NCV) to compute for the

! Lanczos/Arnoldi problem in the Generalized Stability Theory (GST)

! analysis. NCV must be greater than NEV (see documentation below).

NEV = 2 ! Number of eigenvalues

NCV = 10 ! Number of eigenvectors

LcycleTLM == F

NTLM == 72

NDEFTLM == 0

LcycleADJ == F

NADJ == 72

NDEFADJ == 0

LrstGST = F ! GST restart switch

MaxIterGST = 500 ! maximun number of iterations

NGST = 10 ! check pointing interval

Ritz_tol = 1.0d-15

TNU2 == 2*0.0d0 2*0.0d0 2*0.0d0 2*0.0d0 ! m2/s

TNU4 == 2*0.0d0 2*0.0d0 2*0.0d0 2*0.0d0 ! m4/s

VISC2 == 4*0.001d0 ! m2/s

VISC4 == 4*0.0d0 ! m4/s

AKT_BAK == 4*1.0d-6 4*5.0d-6 ! m2/s

AKV_BAK == 4*1.0d-2 4*1.0d-2 ! m2/s

AKK_BAK == 4*5.0d-6 ! m2/s

AKP_BAK == 4*5.0d-6 ! m2/s

TKENU2 == 4*0.0d0 ! m2/s

TKENU4 == 4*0.0d0 ! m4/s

GLS_P == 4*3.0d0 ! K-epsilon

GLS_M == 4*1.5d0

GLS_N == 4*-1.0d0

GLS_Kmin == 4*7.6d-6

GLS_Pmin == 4*1.0d-12

GLS_CMU0 == 4*0.5477d0

GLS_C1 == 4*1.44d0

GLS_C2 == 4*1.92d0

GLS_C3M == 4*-0.4d0

GLS_C3P == 4*1.0d0

GLS_SIGK == 4*1.0d0

GLS_SIGP == 4*1.30d0

RDRG == 4*3.0d-04 ! m/s

RDRG2 == 4*0.003d0 ! nondimensional

Zob == 4*0.0d0 ! m

Zos == 4*00.0d0 ! m

BLK_ZQ == 4*10.0d0 ! air humidity

BLK_ZT == 4*10.0d0 ! air temperature

BLK_ZW == 4*5.0d0 ! winds

DCRIT == 4*0.10d0 ! m

WTYPE == 4*1

LEVSFRC == 4*15

LEVBFRC == 4*1

Vtransform == 4*2 ! transformation equation

Vstretching == 4*3 ! stretching function

THETA_S == 4*7.0d0 ! surface stretching parameter

THETA_B == 4*0.8d0 ! bottom stretching parameter

TCLINE == 4*4.0d0 ! critical depth (m)

RHO0 = 1026.0d0 ! kg/m3

BVF_BAK = 1.0d-5 ! 1/s2

DSTART = 15622 ! days

TIDE_START = 0.0d0 ! days

TIME_REF = 19680523.00 ! yyyymmdd.dd

! TIME_REF = 00010101.00 ! yyyymmdd.dd

! TNUDG == 4*0.0d0 ! days

! ZNUDG == 4*0.01d0 ! days

! M2NUDG == 4*0.01d0 ! days

! M3NUDG == 4*0.01d0 ! days

! OBCFAC == 1.0d0 ! nondimensional

LBC(isFsur) == Clo Gra RadNud RadNud \ ! free-surface, Grid 1

Nes Nes Nes Nes \ ! free-surface, Grid 2

Nes Nes Nes Nes \ ! free-surface, Grid 3

Nes Nes Nes Nes ! free-surface, Grid 4

LBC(isUbar) == Clo FLa Fla Fla \ ! 2D U-momentum, Grid 1

Nes Nes Nes Nes \ ! 2D U-momentum, Grid 2

Nes Nes Nes Nes \ ! 2D U-momentum, Grid 3

Nes Nes Nes Nes ! 2D U-momentum, Grid 4

LBC(isVbar) == Clo FLa Fla Fla \ ! 2D V-momentum, Grid 1

Nes Nes Nes Nes \ ! 2D V-momentum, Grid 2

Nes Nes Nes Nes \ ! 2D V-momentum, Grid 3

Nes Nes Nes Nes ! 2D V-momentum, Grid 4

LBC(isUvel) == Clo Rad Rad Rad \ ! 3D U-momentum, Grid 1

Nes Nes Nes Nes \ ! 3D U-momentum, Grid 2

Nes Nes Nes Nes \ ! 3D U-momentum, Grid 3

Nes Nes Nes Nes ! 3D U-momentum, Grid 4

LBC(isVvel) == Clo Rad Rad Rad \ ! 3D V-momentum, Grid 1

Nes Nes Nes Nes \ ! 3D V-momentum, Grid 2

Nes Nes Nes Nes \ ! 3D V-momentum, Grid 3

Nes Nes Nes Nes ! 3D V-momentum, Grid 4

LBC(isMtke) == Clo Rad Rad Rad \ ! mixing TKE, Grid 1

Nes Nes Nes Nes \ ! mixing TKE, Grid 2

Nes Nes Nes Nes \ ! mixing TKE, Grid 3

Nes Nes Nes Nes ! mixing TKE, Grid 4

LBC(isTvar) == Clo Gra Gra Gra \ ! temperature, Grid 1

Clo Gra Gra Gra \ ! salinity, Grid 1

Nes Nes Nes Nes \ ! temperature, Grid 2

Nes Nes Nes Nes \ ! salinity, Grid 2

Nes Nes Nes Nes \ ! temperature, Grid 3

Nes Nes Nes Nes \ ! salinity, Grid 3

Nes Nes Nes Nes \ ! temperature, Grid 4

Nes Nes Nes Nes ! salinity, Grid 4

! Linear equation of State parameters:

R0 == 4*1026.0d0 ! kg/m3

T0 == 4*17.0d0 ! Celsius

S0 == 4*37.0d0 ! nondimensional

TCOEF == 4*1.7d-4 ! 1/Celsius

SCOEF == 4*7.6d-4

! Slipperiness parameter: 1.0 (free slip) or -1.0 (no slip)

GAMMA2 == 4*1.0d0

! Starting (DstrS) and ending (DendS) day for adjoint sensitivity forcing.

! DstrS must be less or equal to DendS. If both values are zero, their

! values are reset internally to the full range of the adjoint integration.

DstrS == 0.0d0 ! starting day

DendS == 0.0d0