Parameters Reference

Complete list of all input.txt parameters accepted by Tolosa-lct. Parameters shared with Tolosa-sw are documented in the Tolosa-sw Parameters; this page focuses on parameters that are new or differ in Tolosa-lct.

Mesh

Two exclusive modes: if mesh_name is set, the Gmsh file is read and all Cartesian parameters are ignored.

Parameter	Default	Description
mesh_name	null	Gmsh .msh file; if set, Cartesian parameters below are unused
nx, ny	101	Cartesian mesh cell counts
lx, ly	1.	Cartesian mesh physical dimensions (m)
bc_N/S/W/E	wall	Boundary condition per side (see Boundary Conditions)
mesh_type	basic	Cartesian mesh variant
part_strat	seq	Mesh partitioning strategy

Time

time_format controls how dates and durations are interpreted:

time_format	Behavior
classic (default)	No calendar. Duration set by simu_time or ts
julian	start_date and end_date are Julian Day Numbers
julian_cnes	start_date and end_date are CNES Julian Days (epoch: 1950-01-01)
gregorian	start_date and end_date are strings "YYYY-MM-DDThh:mm:ss"

Parameter	Default	Description
time_format	classic	See table above
simu_time	null	Duration: "N seconds/minutes/hours/days"
start_date	null	Start date (format depends on time_format)
end_date	null	End date (optional; overrides simu_time if set)
ts	0.	Fallback duration in seconds when simu_time = null
nt	0	Fixed number of time steps (alternative to simu_time)
cfl	0.5	CFL number (adaptive time step)
dt	-1.	Fixed time step in seconds (overrides CFL if > 0)
adapt_dt	1	Adaptive time step: 1=on, 0=off

Numerical Schemes

Parameter	Default	Description
temp_scheme	1	Temporal scheme: euler/1 (energy-dissipating splitting), 2 (second-order), euler_s2/s2, euler_s3/s3, imex_ssp/ssp (second-order IMEX SSP), imex_ars/ars (second-order IMEX ARS)
spatial_scheme	lm	Spatial scheme: low_mach/lm, low_mach_up/lmup, rusanov/r, pred-corr/pc
spatial_order	1	Order of accuracy: 1=first order, 2=second order (MUSCL)
nb_level	5	Cells used for flux interpolation near discontinuities (Low-Mach only)
bc_control	full	Low-order scheme at boundaries: no, wall, wave, full (wall + inflow)
limit_muscl	h	MUSCL limiter variable: no, h (depth), full (all variables)
gamma	0.5	Low-Mach stabilization constant (gamma*g)
alpha	0.5	Low-Mach stabilization constant (2*alpha*g)
hcut	0.1	Wet/dry threshold (m): dissipative scheme below this depth

Non-Hydrostatic / Acoustic

The NH extension uses an acoustic-like splitting for dispersive pressure terms (w, p). The acoustic speed is derived from the prescribed Mach number so that the acoustic CFL stays manageable.

Parameter	Default	Description
mach	0.2	Target Mach number:
a	1400.	Fixed acoustic speed (m/s), used only when fix_a > 0
alp	1.159	Green-Naghdi dispersive correction coefficient (active with DISP=yes)
fix_a	-1	>0=use constant a, ≤0=local Mach-based
beta	2.	Stability coefficient for the acoustic flux
cfl_ac	0.8	CFL number controlling the acoustic sub-step count
hcut_nh	0.	Depth (m) below which acoustic dispersion is switched off
nb_level_nh	3	Neighbor-cell levels to taper acoustic dispersion near dry cells
nb_step_a	1000	Smoothing iterations for the local acoustic speed field

Wave Breaking

Parameter	Default	Description
wave_break_model	0	0=none, 1=Symphonie-NH viscosity model, 2=enstrophy-based model

Model 1 — Symphonie-NH (wave_break_model=1):

Parameter	Default	Description
brk_crit_slope	0.6	Critical free-surface slope for breaking onset
brk_crit_vel	0.8	Critical velocity ratio for breaking onset
brk_mix_coef	0.1	Momentum mixing coefficient inside the breaker
brk_prod_coef	1.0	Enstrophy production coefficient
brk_ken_coef	5.0	Kinetic energy dissipation coefficient
reinforce_breaker	1.5	Reinforcement factor for the breaking zone
brk_orb_vel	0	Use orbital velocity in breaking criterion: 0=no, 1=yes
wavesetup_window	600.	Time window for wave-setup running average (s)

Model 2 — Enstrophy (wave_break_model=2):

Parameter	Default	Description
Cr	0.48	Iribarren-based breaking criterion
Re_1	2.65	Reynolds parameter 1 (controls onset threshold)
Re_2	64.9	Reynolds parameter 2 (controls saturation)
psi_0_1	0.0205	Lower enstrophy threshold
psi_0_2	1.125	Upper enstrophy threshold
nb_level_surge	6	Neighbor-cell levels for enstrophy diffusion stencil

Bathymetry

Parameter	Default	Description
bathy_in	1	0=flat bottom, 1=from m_user_data.f90, 2=from external file regional.depth-ele.a
bathy_sgn	-1.	Sign convention: -1 means depth is positive downward

Initial State

Parameter	Default	Description
ssh_init	0.	Uniform SSH offset added on top of h0_user at (m); ignored on restart
init_flood	0	Initial flooding algorithm: 0=off, 1=on
init_flood_vtk	0	Write flooded initial state to VTK before time-stepping
cst_phi	1e-12	Isotropic initial enstrophy seed value
cst_phi_x	1e-12	Initial enstrophy seed, x-component
cst_phi_y	1e-12	Initial enstrophy seed, y-component

Friction

Linear (cl) and quadratic (cb) friction can be combined with any model. Spatially variable coefficients are loaded from optional binary files; if absent, the uniform values below are used.

Parameter	Default	Description
friction_model	0	0=none, 1=oceanic quadratic cb, 2=oceanic with z0 (cb from log law), 3=Manning/Strickler
friction_scheme	0	0=explicit, 1=implicit, 2=semi-implicit
cb / cb_min / cb_max	2.5e-3 / 1e-4 / 0.1	Quadratic friction coefficient
cl / cl_min / cl_max	0. / 0. / 1e-2	Linear friction coefficient
cl_relax	0.1	Linear friction in relaxation/sponge zones at walls
hfric	0.1	Minimum water depth used in friction computation (m)
z0	1e-3	Roughness length (m), used by model 2
n / n_min / n_max	0.02 / 1e-3 / 0.1	Manning coefficient, used by model 3
karman	0.41	Von Kármán constant

Coriolis

Parameter	Default	Description
coriolis	0	0=none, 1=spatially variable f from regional.grid-node.a, 2=beta-plane
f0	9.0541e-5	Coriolis parameter f₀ (s⁻¹), used by model 2
beta	1.7876e-11	Beta-plane gradient β (m⁻¹s⁻¹), used by model 2

Atmospheric Pressure

Parameter	Default	Description
patm_forcing	0	0=off, 1=pressure gradient applied to velocity, 2=same + inverse barometer correction at open boundaries
patm_ref_var	0	Reference pressure: 0=constant patm_ref_mean, 1=spatially variable from prmsl_ref.a
patm_ref_mean	101325.	Constant reference atmospheric pressure (Pa)
endian_forcing	little	Endianness of forcing binary files

Wind Stress

Parameter	Default	Description
wind_forcing	0	0=off, >0=on (reads forcing.usst and forcing.vsst)
endian_forcing	little	Endianness of forcing binary files

Tides

Parameter	Default	Description
tbf_forcing	0	Tidal body force: 0=off, >0=on (from tide.list)
dt_tbf	600.	Update interval for tidal body force (s)
tide_is_ramp	0	Tidal ramp-up: 1=on, 0=off
tide_time_ramp	3600.	Duration of tidal ramp-up (s)
endian_ssht	little	Endianness of ssht_edge_at_bc.a

Wave Maker / Relaxation Boundaries

Parameter	Default	Description
frelax	exp6	Shape of the relaxation function for wave generation/absorption zones
frwall	sin	Shape of the relaxation function at reflective wall boundaries
nb_pt_sampling_wbc	80	Quadrature points for wave BC flux integration
nb_period_ramp_wbc	10	Wave periods over which the wave BC is ramped up

MPI

Parameter	Default	Description
mpi_choice	2	Communication strategy: 0=library default, 1=local non-blocking, 2=persistent (MPI_SSend_Init), 3=persistent with additional optimizations

Physical Constants and Profiling

Parameter	Default	Description
g	9.81	Gravitational acceleration (m/s²)
heps	1e-13	Minimum water depth threshold
profile	-1	Profiling level: -1=off, 1=MPI wait timer, 2=write to file, 3=both

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For external file formats (binary forcing files, tide.list, wave spectrum, etc.), see External Input Files.