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SWAN. N = wave action density (energy density / relative frequency). cx, cy = propagation velocities ( x- and y- directions) s = relative frequency = wave direction S = source/sink term for: - wind-wave generation - wave breaking - bottom dissipation
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SWAN N = wave action density (energy density / relative frequency) • cx, cy = propagation velocities (x- and y- directions) • s = 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. 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.
SWAN User's manual http://swanmodel.sourceforge.net/online_doc/swanuse/swanuse.html
Input file - to run SWAN by itself SWAN is driven by a series of 'KEYWORDS' in the input file. 'PROJECT' 'MODE' 'SET' 'CGRID' 'READGRID' etc etc Projects/Inlet_Test/Swanonly/swan_inlet_test.in
Input file - control commands PROJECT - 4 text lines SET - DEPMIN to be same as Dcrit - INRHOG 1 !!!!!! - NAUTICAL !!!! COORDINATES - SPHERICAL or CARTESIAN MODE NONSTAT TWOD
Input file - computational grid CGRID and READGRID: Defines the computational grid in x, y, freq, and theta space.
Input file - input grids INPGRID and READINP: Input grid for variables of bottom, waterlevel, currents, winds, etc. This is for the BOTTOM (bathymetry)
Input file - to run SWAN by itself INPGRID 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 inputs BOUND SHAPE BOUND SIDE or BOUND SEGMENT
Input file - Boundary inputs BOUND SHAPE BOUND SIDE or BOUND SEGMENT THIS command uses I J indices along a segment
Input file - Boundary inputs BOUND SHAPE BOUND SIDE or BOUND SEGMENT THIS command uses X Y indices along a segment with input files
TPAR file Lists the date, Hsig, Period, Direction, and Spreading factor
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:end to 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
1) cppdefs.h just do SWAN MODEL for now will ad refined grid later
2) grids create_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 run roms2swan(x, y, depth, mask) for example, the bottom of the create_roms_xy_grid calls to roms2swan. This creates 2 files: grid_coord.grd (goes with READGRID COORDS) swan_bathy.bot (goes with READINP BOTTOM)
3) wind forcing Can use Tools\mfiles\mtools\narr2romsnc.m At 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.m To read WW3 model output and create SWAN TPAR boundary forcing files.
5) INPUT Projects/Inlet_Test/Swanonly/swan_inlet_test.in
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 ATM Uwind, Vwind WAV 1) Generation – wind speed forcing is modified by ocean currents: S(w) = f( Uwind – us ; Vwind – vs ) us, vs, h, bath, Z0 OCN 2) Propagation – wave celerity in geographic space is modified by ocean currents cx = cgx + us ; cy = cgy + vs – change of wave direction (refraction) due to h, bathy, and currents:
To activate these processes in SWAN Need to activate CURRENT WLEV FRIC to get data from ROMS Need to activate WIND to get data from WRF No READINP since this data is coming from ROMS Grid dims don’t really matter. It gets the data from the other model thru MCT.
OCN interactions Hwave, Lmwave, Lpwave, Dwave, Tpsurf, Tmbott, Qb, Dissbot, Disssurf, Disswcap, Ubot OCN WAVE #define CRAIG_BANNER #define CHARNOK or #define ZOS_HSIG #define TKE_WAVEDISS #define COARE_OOST #define COARE_TAYLOR_YELLAND #define DRENNAN CRAIG_BANNER (default) #define WEC_VF #define SSW_BBL Water column Surface stress Bottom stress t Stokes + VF Surface tke flux s= f ( Zos ) Zoa t b = f ( Zob ) Hwave, Lmwave, Dwave, Tpsurf, Qb, Dissbot, Disssurf, Disswcap, Hwave, Lpwave, Dwave, Tpsurf, Hwave, Lpwave, Dwave, Tpsurf, Hwave, Lmwave, Dwave, Tmbott, Ubot
ATM interactions ATM Hwave, Lpwave, Tpsurf, SST OCN WAV OCN SST Momentum Heat Surface fluxes Moisture = f ( Hwave, Lpwave, Tpsurf ) WAV
SURFACE ROUGHNESS CLOSURE MODELS Currently only in MYJSFC and MYNN CHARNOCK 1955 (default) TAYLOR & YELLAND 2001: TY2001 (#define COARE_TAYLOR_YELLAND) - Wave steepness based parameterization. - Based on three datasets representing sea-state conditions ranging from strongly forced to shoaling. DRENNAN 2003: DGQH (#define DRENNAN) • 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. OOST 2002: OOST (#define COARE_OOST) - Wave age dependent formula but it also considers the effect of the wave steepness.
Applications • Nor Ida (Nov 2009) • (waves) http://www.hpc.ncep.noaa.gov/dailywxmap/
Nor’Ida Nov 2009 wind speed 23 m/s (50 mph) H Wave heights (m) Bodie Island, NC 13thNov L L 11thNov 10thNov Wallops Island, VA Before 9th Nov 8th Nov Before wind speed 40 m/s (90 mph) After http://coastal.er.usgs.gov/hurricanes/norida/ After
MCT MCT COAWST (Coupled Ocean – Atmosphere – Wave – Sediment Transport) Modeling System ATMOSPHERE Hsig, Lwave, , Twave, Uwind, Vwind, Patm, RH, Tair, cloud, rain, SWrad, LWrad, LHeat, SHeat Latitude SST WRF wind speed Uwind, Vwind Longitude WAVE SWAN Hsig OCEAN ROMS SST Hsig, Lwave, Dwave, Tsurf, Tbott,Qb, Wdissip, Ub MCT us, vs, h, bath
SST WRF + ROMS + SWAN WRF GOES WRF + ROMS
WINDS WRF + ROMS WRF DATA WRF WRF+ROMS WRF+ROMS+SWAN WRF + ROMS + SWAN Reduced wind speed with waves coupling. m/s S 0.85 0.78 0.89
WAVES WRF WRF + SST WRF + SST +OOST m WRF + ROMS + SWAN WRF WRF + ROMS DATA WRF WRF+ROMS WRF+ROMS+SWAN Reduced waves with waves coupling. S 0.80 0.74 0.88
WINDS WRF + ROMS + SWAN( ) (OOST) (DGQH) (TY) WRF + SST + TY2001 WRF + SST + DGQH SST + WRF WRF + ROMS Reduced wind speed with waves coupling. OOST best. DATA WRF WRF+ROMS W+R+S (DGQH) W+R+S (TY2001) W+R+S (OOST) NAM WRF +SST + OOST m/s
WAVES WRF + ROMS + SWAN( ) (OOST) (DGQH) (TY) WRF + SST + TY2001 WRF + SST + DGQH WRF + ROMS Reduced wave heights with waves coupling. OOST best. DATA WRF WRF+ROMS W+R+S (DGQH) W+R+S (TY2001) W+R+S (OOST) NAM WRF + SST +OOST m
WRF + SST + TY2001 SURFACE CURRENTS WRF + ROMS + SWAN( ) WRF + SST + DGQH (OOST) (DGQH) (TY) m/s WRF + SST + OOST Increased current speed with waves coupling. TY / DGQH best. CODAR WRF + ROMS (charnock) m/s
SURFACE CURRENTS WRF + ROMS + SWAN( ) WRF + SST + DGQH (OOST) (DGQH) (TY) Model currents (m/s) RMSE (m/s) 0.14 RMSE (m/s) 0.13 RMSE (m/s) 0.26 CODAR currents (m/s) CODAR currents (m/s) CODAR currents (m/s) Increased current speed with waves coupling. TY / DGQH best. CODAR WRF + ROMS (charnock) m/s RMSE (m/s) 0.24
STORM SURGE WRF WRF + ROMS + SWAN( ) (OOST) (DGQH) (TY) WRF+ SST + OOST m WRF + ROMS DATA WRF WRF+ROMS W+R+S (DGQH) W+R+S (TY2001) W+R+S (OOST) Increased surge with waves coupling. TY / DGQH best?