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SWANyx w
c Nc N c N c N SN
t x y
cx, cy = propagation velocities (x- and y- directions) = relative frequency = wave direction
S = source/sink term for: - wind-wave generation - wave breaking - bottom dissipation - nonlinear wave-wave interactions
SWAN accounts for shoaling, diffraction, partial transmission, and reflection.
N = wave action density (energy density / relative frequency)
Booij, N., R.C. Ris and L.H. Holthuijsen, 1999, A third-generation wave model for coastal regions, Part I, Model description and validation, J.Geoph.Research, 104, C4, 7649-7666.Booij, N., R.C. Ris and L.H. Holthuijsen, 1999, A third-generation wave model for coastal regions, Part II, Model description and validation, J.Geoph.Research, 104, C4, 7649-7666.Booij, N., Haagsma, IJ.G., Holthuijsen, L.H., Kieftenburg, A.T.M.M., Ris, R.C., van der Westhuysen, A.J., and Zijlema, M. (2004). SWAN Cycle III version 40.41 User Manual, Delft University of Technology.
Input file - to run SWAN by itselfSWAN is driven by a
series of 'KEYWORDS' in the
input file.
'PROJECT''MODE'
'SET''CGRID'
'READGRID'
etcetc
Projects/Inlet_Test/Swanonly/swan_inlet_test.in
Input file - control commandsPROJECT - 4 text lines
SET - DEPMIN to be same as Dcrit - INRHOG 1 !!!!!! - NAUTICAL !!!!
COORDINATES - SPHERICAL or CARTESIAN
MODE NONSTAT TWOD
Input file - computational gridCGRID and READGRID: Defines the computational grid in x, y, freq, and theta space.
Input file - input gridsINPGRID and READINP: Input grid for variables of bottom, waterlevel, currents, winds, etc.
This is for the BOTTOM (bathymetry)
Input file - to run SWAN by itselfINPGRID and READINP: Input grid for variables of bottom, waterlevel, currents, winds, etc.
This is an example for WIND
We typically use IDLA = 4
Input file - Boundary inputsBOUND SHAPEBOUND SIDE or BOUND SEGMENT
THIS command uses I J indices along a segment
Input file - Boundary inputsBOUND SHAPEBOUND SIDE or BOUND SEGMENT
THIS command uses X Y indices along a segmentwith input files
Input file - Init files
Can start SWAN with data from an init file.This file can be created from a STATIONARY run.
Input file - Output and run
start dt end
Can make this as STATIONARY, then don’t need start:dt:endto get init conditions files.
How to create a SWAN application
1) cppdefs.h 2) grids 3) wind forcing 4) boundary conditions 5) INPUT 6) coawst.bash 7) run it
2) gridscreate_roms_xy_grid
1) you can use the CGRID Regular command
or
2) create a ROMS grid using any of the tools mentioned before, then runroms2swan(x, y, depth, mask)
for example, the bottom of the create_roms_xy_gridcalls to roms2swan. This creates 2 files:
grid_coord.grd (goes with READGRID COORDS)swan_bathy.bot (goes with READINP BOTTOM)
3) wind forcingCan use Tools\mfiles\mtools\narr2romsnc.mAt the end of this file, it creates the wind forcing file for SWAN.Need to add this wind file name to READINP WIND.
4) boundary conditions - TPAR
Can use Tools\mfiles\swan_forc\ww3_swan_input.mTo read WW3 model output and create SWAN TPAR boundary forcing files.
6) coawst.bash7) run it
Build it by setting the Project name and paths in the coawst.bash.
Run it by call to coawstM, but now need to explicitly state input file name
mpiexec -np 4 ./coawstM Projects/Inlet_test/Swanonly/swan_inlet_test.in
SWAN with grid refinement
#define SWAN_MODEL #define REFINED_GRID comile with nested_grids = 2 (or however
many) need 2 (or more) INPUT files. mpirun -np X ./coawstM
Projects/Inlet_test/Swanonly/swan_inlet_test.in
Projects/Inlet_test/Swanonly/swan_inlet_test_ref5.in
SWAN Coupling
Interactions to ocean and atm models.
This will happen in you
#define SWAN_MODEL
and one more of:
#define ROMS_MODEL
#define WRF_MODEL
WAV interactions
1) Generation – wind speed forcingis modified by ocean currents:
S(w) = f( Uwind – us ; Vwind – vs )
us, vs, , bath, Z0
Uwind , V
wind
WAV
OCN
ATM
2) Propagation
yx wc Nc N c N c N SN
t x y
– wave celerity in geographic space is modified by ocean currents cx = cgx + us ; cy = cgy + vs
, sin cos cos sin cos sin sin cossinh 2g
h h U U V VC
kh x y x y x y
– change of wave direction (refraction) due to , bathy, and currents:
To activate these processes in SWAN
Need to activate CURRENT
WLEVFRIC
to get data from ROMS
No READINP since this datais coming from ROMS
Need to activate WIND
to get data from WRF
Grid dims don’t really matter. It gets the data from the other model
thru MCT.
OCN interactionsWAVE
Hwave, Lmwave, Lpwave, Dwave,Tpsurf, Tmbott, Qb, Dissbot, Disssurf, Disswcap, Ubot
OCN
Hwave, Lmwave, Dwave,Tpsurf, Qb, Dissbot, Disssurf, Disswcap,
Water column
Stokes + VF
Hwave, Lpwave, Dwave, Tpsurf,
Hwave, Lmwave, Dwave,Tmbott, Ubot
Surface stress Bottom stress
s= f ( Zos ) Zoa
b = f ( Zob )
#define WEC_VF
#define CRAIG_BANNER#define CHARNOKor#define ZOS_HSIG#define TKE_WAVEDISS #define SSW_BBL
Hwave, Lpwave, Dwave, Tpsurf,
Surface tke flux
#define COARE_OOST#define COARE_TAYLOR_YELLAND#define DRENNANCRAIG_BANNER (default)
ATM interactions
OCN
ATM
WAV
SST
Hwave , L
pwave ,
Tpsurf ,
Sur
face
flu
xes
Momentum
Heat
Moisture
= f ( Hwave, Lpwave, Tpsurf )
SST OCN
WAV
SURFACE ROUGHNESS CLOSURE MODELSCurrently only in MYJSFC and MYNN
TAYLOR & YELLAND 2001: TY2001 (#define COARE_TAYLOR_YELLAND)
DRENNAN 2003: DGQH (#define DRENNAN)
OOST 2002: OOST (#define COARE_OOST)
4.50 1200ms p
s
zH L
H
- Wave steepness based parameterization.- Based on three datasets representing sea-state conditions ranging from strongly forced to shoaling.
3.40*3.35m
ps
zu C
H
4.50*
25.0mp
p
zu C
L
- Wave age dependent formula but it also considers the effect of the wave steepness.
- Wave age based formula to characterize the ocean roughness. - They combined data from many field experiments representing a variety of condition and grouped the data as a function of the wind friction velocity.
0
*
*
significant wave height
ocean surface roughness
wind friction velocity
peak wave celerity
peak wave length
wave age
s
p
p
p
H
z
u
C
L
u
C
CHARNOCK 1955 (default)
2*0
0.011m
uz
g
Nor’Ida Nov 2009
Bodie Island, NC
Wallops Island, VA
LL
LL
HH
8th Nov8th Nov
9th Nov9th Nov
10thNov10thNov
11thNov11thNov
13thNov13thNov
wind speed23 m/s (50 mph)
wind speed23 m/s (50 mph)
Before
Before
After
Afterhttp://
coastal.er.usgs.gov/hurricanes/norida/
Wav
e h
eigh
ts (m
)
wind speed40 m/s (90 mph)
wind speed40 m/s (90 mph)
OCEAN
ATMOSPHERE
WAVE
us, vs, , bath
Hsig, Lwave, Dwave,Tsurf, Tbott,Qb, Wdissip, Ub
MCT
Uwind, Vwind, P
atm, R
H, Tair,
cloud, ra
in, SW
rad, LW
rad, LHeat,
SHeat
SST
MCT
Uwind,
Vwind
MCT
WRF wind speed
LongitudeLa
titud
e
ROMS SSTSWAN Hsig
COAWST (Coupled Ocean – Atmosphere – Wave – Sediment Transport) Modeling System
Hsig, L
wave , ,
Twave ,
WRF
WINDSWRF + ROMS + SWAN m/sWRF + ROMS
S
0.850.780.89
DATAWRF
WRF+ROMSWRF+ROMS+SWAN
Reduced wind speed with waves coupling.
WAVESWRF
WRF + SST +OOST WRF + SST
DATAWRF
WRF+ROMSWRF+ROMS+SWAN
WRF + ROMS + SWANWRF + ROMSWRF
S
0.800.740.88
m
Reduced waves with waves coupling.
WRF +SST + OOST m/s
SST + WRF
WINDSWRF + SST + TY2001 WRF + SST + DGQH
DATAWRF
WRF+ROMS W+R+S (DGQH)W+R+S (TY2001)W+R+S (OOST)
NAM
(TY)WRF + ROMS + SWAN( )
(OOST)
WRF + ROMS
(DGQH)
Reduced wind speed with waves coupling.OOST best.
WRF + SST +OOST m
WAVES
DATAWRF
WRF+ROMS W+R+S (DGQH)W+R+S (TY2001)W+R+S (OOST)
NAM
WRF + ROMS
WRF + SST + TY2001 WRF + SST + DGQH(TY)
WRF + ROMS + SWAN( )(OOST) (DGQH)
Reduced wave heights with waves coupling.OOST best.
WRF + SST + DGQH
SURFACE CURRENTS
WRF + ROMS (charnock)
m/s
m/s
WRF + SST + TY2001WRF + SST + OOST (TY)WRF + ROMS + SWAN( )
(OOST) (DGQH)
CODARIncreased current speed with waves coupling.
TY / DGQH best.
WRF + SST + DGQH
SURFACE CURRENTS
WRF + ROMS (charnock)
m/s
(TY)WRF + ROMS + SWAN( )
(OOST) (DGQH)
CODAR
RMSE (m/s) 0.24
RMSE (m/s) 0.14RMSE (m/s) 0.13RMSE (m/s) 0.26
Mod
el c
urre
nts
(m/s
)
CODAR currents (m/s) CODAR currents (m/s) CODAR currents (m/s)Increased current speed with waves coupling.
TY / DGQH best.