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Parameter Reference

This document maps XBeach parameters to their location in rompy-xbeach components.

The structure follows the rompy-xbeach component hierarchy, with references to the corresponding XBeach manual tables. This ensures consistency between the documentation and the actual code structure.

Finding Parameters

  • By rompy-xbeach component: Use the sections below (Physics, Sediment, Output, etc.)
  • By XBeach table: Look for the table reference in each section header (e.g., "Table 36")
  • By XBeach parameter name: Use your browser's search (Ctrl+F / Cmd+F)

Physics Component

The Physics component controls wave models, flow computation, friction, viscosity, and related numerical settings.

Process Switches

XBeach Parameter Rompy Location Description
wavemodel physics.wavemodel Wave model type (stationary/surfbeat/nonh)
swave physics.swave Enable short wave action balance
lwave physics.lwave Enable long wave propagation
flow physics.flow Enable flow computation
avalanching physics.avalanching Enable avalanching
gwflow physics.gwflow Enable groundwater flow
wind physics.wind Enable wind forcing
vegetation physics.vegetation Enable vegetation effects
ships physics.ships Enable ship-induced waves
roller physics.roller Enable roller model
wci physics.wci Wave-current interaction

Wave Model Parameters

XBeach Parameter Rompy Location Description
break physics.wavemodel.breaktype Breaker formulation
gamma physics.wavemodel.breaktype.gamma Breaker parameter
alpha physics.wavemodel.breaktype.alpha Wave dissipation coefficient
n physics.wavemodel.breaktype.n Power in breaker formulation
gammax physics.wavemodel.breaktype.gammax Maximum ratio Hb/hb
single_dir physics.wavemodel.single_dir Single directional bin (Surfbeat)
nhbreaker physics.wavemodel.nhbreaker Non-hydrostatic breaker (Nonh)
solver physics.wavemodel.solver Pressure solver (Nonh)
Topt physics.wavemodel.Topt Optimal timestep (Nonh)
kdmin physics.wavemodel.kdmin Minimum kd for dispersion (Nonh)

Bed Friction Parameters

XBeach Parameter Rompy Location Description
bedfriction physics.bedfriction Bed friction formulation
bedfriccoef physics.bedfriction.bedfriccoef Friction coefficient
bedfricfile physics.bedfriction.bedfricfile Spatially varying friction file

Viscosity Parameters

XBeach Parameter Rompy Location Description
nuh physics.viscosity.nuh Horizontal viscosity coefficient
nuhfac physics.viscosity.nuhfac Viscosity calibration factor
smag physics.viscosity.smag Enable Smagorinsky model

Wave Numerics

XBeach Parameter Rompy Location Description
scheme physics.wave_numerics.scheme Numerical scheme
wavint physics.wave_numerics.wavint Wave integration interval
maxerror physics.wave_numerics.maxerror Maximum wave convergence error
maxiter physics.wave_numerics.maxiter Maximum wave iterations

Flow Numerics

XBeach Parameter Rompy Location Description
cfl physics.flow_numerics.cfl CFL criterion
eps physics.flow_numerics.eps Threshold depth
hmin physics.flow_numerics.hmin Minimum water depth
umin physics.flow_numerics.umin Minimum velocity
secorder physics.flow_numerics.secorder Second-order advection
oldhu physics.flow_numerics.oldhu Old hu/hv formulation

Physical Constants

XBeach Parameter Rompy Location Description
rho physics.constants.rho Water density
rhoa physics.constants.rhoa Air density
g physics.constants.g Gravitational acceleration
lat physics.constants.lat Latitude for Coriolis
wearth physics.constants.wearth Earth angular velocity

Vegetation Parameters

XBeach Parameter Rompy Location Description
vegetation physics.vegetation Enable vegetation
nsec physics.vegetation.nsec Number of vegetation sections
ah physics.vegetation.ah Vegetation height
bv physics.vegetation.bv Stem diameter
Nv physics.vegetation.Nv Stem density
Cd physics.vegetation.Cd Drag coefficient

Sediment Component

The Sediment component controls sediment transport, morphology, bed composition, and groundwater flow. This corresponds to XBeach Tables 36-41.

Process Switches

The main switches sedtrans and morphology are fields on the Sediment component, not Physics. Set sediment.sedtrans=True or provide a SedimentTransport object to enable sediment transport.

Sediment Transport (XBeach Table 36)

XBeach Parameter Rompy Location Description
form sediment.sedtrans.form Transport formulation
waveform sediment.sedtrans.waveform Wave shape formulation
turb sediment.sedtrans.turb Turbulence formulation
sws sediment.sedtrans.sws Short wave stirring
lws sediment.sedtrans.lws Long wave stirring
lwt sediment.sedtrans.lwt Long wave turbulence
BRfac sediment.sedtrans.BRfac Bore runup factor
facua sediment.sedtrans.facua Onshore transport factor
facAs sediment.sedtrans.facAs Skewness factor
facSk sediment.sedtrans.facSk Asymmetry factor

Morphology (XBeach Table 39)

XBeach Parameter Rompy Location Description
morfac sediment.morphology.morfac Morphological acceleration
morstart sediment.morphology.morstart Morphology start time
morstop sediment.morphology.morstop Morphology stop time
wetslp sediment.morphology.wetslp Critical wet slope
dryslp sediment.morphology.dryslp Critical dry slope
struct sediment.morphology.struct Enable structures
ne_layer sediment.morphology.ne_layer Non-erodible layer file

Bed Update (XBeach Table 40)

XBeach Parameter Rompy Location Description
fwfile sediment.bed_update.fwfile Wave friction file
fwcutoff sediment.bed_update.fwcutoff Wave friction cutoff

Bed Composition

XBeach Parameter Rompy Location Description
D50 sediment.bed_composition.D50 Median grain size
D90 sediment.bed_composition.D90 90th percentile grain size
D15 sediment.bed_composition.D15 15th percentile grain size
ngd sediment.bed_composition.ngd Number of grain classes
nd sediment.bed_composition.nd Number of bed layers
rhos sediment.bed_composition.rhos Sediment density
por sediment.bed_composition.por Porosity
dzg1 sediment.bed_composition.dzg1 Layer 1 thickness
dzg2 sediment.bed_composition.dzg2 Layer 2 thickness
dzg3 sediment.bed_composition.dzg3 Layer 3 thickness
sedcal sediment.bed_composition.sedcal Sediment calibration factor
ucrcal sediment.bed_composition.ucrcal Critical velocity calibration

Groundwater Flow (XBeach Table 41)

Groundwater Switch

The main switch gwflow is on the Physics component (physics.gwflow), but the detailed groundwater parameters are on Sediment.groundwater.

XBeach Parameter Rompy Location Description
gwflow physics.gwflow Enable groundwater flow (on Physics)
gwnonh sediment.groundwater.gwnonh Non-hydrostatic groundwater
kx sediment.groundwater.kx Horizontal permeability
ky sediment.groundwater.ky Vertical permeability
gwheadmodel sediment.groundwater.gwheadmodel Head boundary model

Boundary Conditions

Boundary conditions are configured at the Config level, not within Physics or Sediment components.

Flow Boundary Parameters

XBeach Parameter Rompy Location Description
front flow_boundary.front Front boundary type
back flow_boundary.back Back boundary type
left flow_boundary.left Left boundary type
right flow_boundary.right Right boundary type
lateralwave flow_boundary.lateralwave Lateral wave boundary

Tide Boundary Parameters

XBeach Parameter Rompy Location Description
tideloc tide_boundary.tideloc Number of tide locations
tidetype tide_boundary.tidetype Tide boundary type
zs0 tide_boundary.zs0 Initial water level
paulrevere tide_boundary.paulrevere Sea/land boundary

Wave Boundary Parameters

XBeach Parameter Rompy Location Description
wbctype wave_boundary.wbc.wbctype Wave boundary type
bcfile wave_boundary.wbc.bcfile Boundary condition file
dtbc wave_boundary.wbc.dtbc Boundary update interval
thetamin wave_boundary.wbc.thetamin Minimum wave direction
thetamax wave_boundary.wbc.thetamax Maximum wave direction
dtheta wave_boundary.wbc.dtheta Directional resolution
thetanaut wave_boundary.wbc.thetanaut Nautical convention
ARC wave_boundary.wbc.ARC Active reflection compensation
freewave wave_boundary.wbc.freewave Free wave boundary

Hotstart Component

The Hotstart component enables initialization from a previous simulation state.

Hotstart Parameters

XBeach Parameter Rompy Location Description
hotstart hotstart Enable hotstart
hotstartfileno hotstart.hotstartfileno Hotstart file number
writehotstart output.writehotstart Write hotstart files
tinth output.tinth Hotstart output interval

Output Component

The Output component controls what variables are written and at what intervals.

Output Parameters

XBeach Parameter Rompy Location Description
outputformat output.outputformat Output file format
tintg output.tintg Global output interval
tintm output.tintm Mean output interval
tintp output.tintp Point output interval
tstart output.tstart Output start time
nglobalvar output.globalvars Computed from globalvars list length
nmeanvar output.meanvars Computed from meanvars list length
npointvar output.pointvars Computed from pointvars list length
nrugauge output.rugauges Computed from rugauges list length
nrugdepth output.nrugdepth Number of runup depths
rugdepth output.rugdepth Runup depth thresholds

MPI Component

The Mpi component controls domain decomposition for parallel execution.

MPI Parameters

XBeach Parameter Rompy Location Description
mpiboundary mpi.mpiboundary MPI boundary type
mmpi mpi.mmpi MPI partitions in m
nmpi mpi.nmpi MPI partitions in n

Data-Driven Parameters

These parameters are generated automatically by data interface classes. They should not be set manually - instead, configure the appropriate data source and the parameters will be computed during model generation.

Grid Parameters

Generated by RegularGrid from grid.py:

XBeach Parameter Source Description
nx grid.nx - 1 Number of computational cells in x-direction
ny grid.ny - 1 Number of computational cells in y-direction
dx grid.dx Grid spacing in x-direction
dy grid.dy Grid spacing in y-direction
xori grid.x0 X-coordinate of grid origin
yori grid.y0 Y-coordinate of grid origin
alfa grid.alfa Angle of x-axis from east (degrees)
projection grid.proj4 PROJ4 projection string

Bathymetry Parameters

Generated by bathymetry data classes:

XBeach Parameter Source Description
depfile bathy.get() Bathymetry file name
posdwn bathy.get() Positive down convention (1 or -1)
vardx bathy.get() Variable grid spacing flag

Water Level / Tide Parameters

Generated by WaterLevelGrid, TideConsGrid, etc. from data/waterlevel.py:

XBeach Parameter Source Description
zs0file input.tide.get() Tide/water level time series file
tideloc input.tide.tideloc Number of tide boundary locations (1, 2, or 4)
tidelen input.tide.get() Number of time steps in tide series

Wind Parameters

Generated by WindGrid, WindStation, WindPoint from data/wind.py:

XBeach Parameter Source Description
windfile input.wind.get() Wind forcing file (contains windv, windth time series)

Wave Boundary Parameters

Generated by boundary classes in data/boundary.py. These return a SpectralWaveBoundary specification:

XBeach Parameter Source Description
wbctype input.wave.id Wave boundary type (jons, jonstable, swan, etc.)
bcfile input.wave.get() Wave boundary condition file or FILELIST

JONS/Parametric boundaries (BoundaryStationParamJons, BoundaryGridParamJons, etc.):

XBeach Parameter Source Description
Hm0 Data-derived Significant wave height
Tp Data-derived Peak period
mainang Data-derived Main wave direction
gammajsp Data-derived JONSWAP peak enhancement factor
s Data-derived Directional spreading coefficient
fnyq input.wave.fnyq Nyquist frequency for spectrum
dfj input.wave.dfj Frequency step for spectrum

JONSTABLE boundaries (BoundaryStationParamJonstable, BoundaryGridParamJonstable, etc.):

XBeach Parameter Source Description
Hm0 Data-derived (time series) Significant wave height
Tp Data-derived (time series) Peak period
mainang Data-derived (time series) Main wave direction
gammajsp Data-derived (time series) JONSWAP gamma
s Data-derived (time series) Spreading coefficient
duration Computed from times Duration of each condition
dtbc input.wave.wbc.dtbc Boundary update timestep

SWAN spectral boundaries (BoundaryStationSpectraSwan):

XBeach Parameter Source Description
freq Data-derived Frequency array
dir Data-derived Direction array
efth Data-derived 2D energy density spectrum

Wave Boundary Condition Parameters

These can be set via input.wave.wbc (a SpectralWaveBoundaryConditions object):

XBeach Parameter Source Description
dtbc input.wave.wbc.dtbc Boundary condition timestep
nmax input.wave.wbc.nmax Maximum ratio cg/c for long waves
rt input.wave.wbc.rt Duration of wave spectrum
taper input.wave.wbc.taper Spin-up time for boundary
fcutoff input.wave.wbc.fcutoff Low-frequency cutoff
sprdthr input.wave.wbc.sprdthr Spreading threshold
trepfac input.wave.wbc.trepfac Representative period factor
correcthm0 input.wave.wbc.correcthm0 Correct Hm0 for directional spreading
random input.wave.wbc.random Random seed for boundary generation
nspr input.wave.wbc.nspr Long wave direction switch
wbcversion input.wave.wbc.wbcversion Wave boundary version
wbcRemoveStokes input.wave.wbc.wbcRemoveStokes Remove Stokes drift
wbcScaleEnergy input.wave.wbc.wbcScaleEnergy Scale energy to match Hm0

Data Interface Pattern

The data interfaces follow a consistent pattern: configure the source data and variable mappings, then call get(destdir, grid, time) which writes the necessary files and returns a dict or object with the XBeach parameters to include in params.txt.