CMS-Flow Wind Forcing
Wind Curve
Temporally varying, spatially constant winds are input in CMS in the Wind Section of the CMS-Flow Model Control Window. To add wind forcing to a current CMS-Flow project click on CMS-Flow | Model Control and then on the Wind/Wave tab. Activate wind forcing by clicking on the Include Wind check box. Winds may be imported using an *.m2w file or by specifying a curve for wind speed and direction. To specify a curve for each click on the respective box which says Curve undefined which will open the XY Series Editor. The time series may be manually entered, copied or imported from an *.xys file in the XY Series Editor.
Spatially Variable Wind and Atmospheric Pressure
CMS-Flow V4.0 and higher have the option to use spatially variable wind and atmospheric pressure forcing. Currently, this feature is specified in the advanced card section.
- Notes:
- Interpolation File: When using spatially variable winds CMS V4.0 will output a file named Intpcoef_wndfl.bin. This file contains the coefficients used to interpolate the winds and atmospheric pressure to the CMS-Flow grid. If the same flow and wind grids are run, the model will automatically detect the interpolation file and read in the coefficients instead of calculating them. If the either grid is changed in size, the model will automatically detect this and recalculate the coefficients. However, if the grids are changed but stay the same size, the model will not be able to detect that they have changed. Therefore, whenever any changes are made to the flow or wind grids, it is best to delete the interpolation file.
- Ramp Period: During the ramp period, the ramp is applied to both the wind shear stresses and spatial variations of the atmospheric pressure.
Oceanweather Format
CMS-Flow cards related to wind
| Card | Arguments | Type |
|---|---|---|
| WIND_OUT_TIMES_LIST | Id number of output times list | integer |
| WIND_DRAG_COEFFICIENT | kappa in Hsu (1988) (default 0.4) | real |
| WIND_INPUT_CURVE | Name of model parameter file followed wind curve path | character |
| ANEMOMETER_HEIGHT | Height of wind speeds | meter |
| OCEANWEATHER_WIND_FILE | Name of Oceanweather, Inc. wind file (*.win) | character |
| OCEANWEATHER_PRES_FILE | Name of Oceanweather, Inc. pressure file (*.pre) | character |
| OCEANWEATHER_XY_FILE | Name of Oceanweather, Inc. coordinate file (*.xy) | character |
Oceanweather Wind File Format
The file format for the Oceanweather wind file (*.win) is best described with an example:
Oceanweather WIN/PRE Format 2008090912 2008091406
iLat= 118iLong= 201DX=0.0150DY=0.0150SWLat=28.50000SWLon=-96.0000DT=200809091200
-4.8891 -4.8873 -4.8855 -4.8838 -4.8821 -4.8805 -4.8789 -4.8774
-4.8759 -4.8744 -4.8730 -4.8717 -4.8704 -4.8692 -4.8680 -4.8669
...
-2.1530 -2.1382 -2.1233 -2.1085 -2.0937 -2.0788 -2.0637 -2.0486
-2.0335 -2.0184 -2.0035 -1.9887 -1.9741 -1.9598 -1.9458 -1.9322
-1.9190 -1.9062 -1.8938 -1.8820 -1.8707 -1.8600
iLat= 118iLong= 201DX=0.0150DY=0.0150SWLat=28.50000SWLon=-96.0000DT=200809091215
-4.9107 -4.9090 -4.9074 -4.9058 -4.9043 -4.9028 -4.9014 -4.9001
-4.8988 -4.8975 -4.8963 -4.8952 -4.8942 -4.8932 -4.8923 -4.8914
-4.8906 -4.8898 -4.8889 -4.8881 -4.8873 -4.8866 -4.8860 -4.8854
...
The last two arguments of the header is are the starting and end times in yyyymmddhh. The wind data is preceded by a header line with the grid information. iLat and iLong are latitude North and longitude West. DX and DY are the grid spacing in units of degrees. SWLat and SWLon are the coordinates of the south-west grid point. DT is the actual time in yyyymmddhhMM. First the wind velocities in the x-direction are read than the velocities in the y-direction. The wind speeds are written in m/s.
FORTRAN CODE
An excerpt of the FORTRAN code used to read the file is shown below:
open(nunit,file=windfile,status='old') read(nunit,*) !skip header 11 format(t6,i4,t16,i4) read(nunit,11) nwindi, nwindj backspace(nunit) !... 13 format(68x,I4,4(I2)) read(nunit,13,end=333,err=333) iyear,imonth,iday,ihour,imin !... 12 format(8f10.0) read(nunit,12,end=333,err=333) ((wndspdx(i,j),j=1,nwindj),i=1,nwindi) read(nunit,12,end=333,err=333) ((wndspdy(i,j),j=1,nwindj),i=1,nwindi) !... 333 close(nunit)
Single ASCII File
This file format is equivalent to the ADCIRC fort.22 format with NWS=6. The winds and atmospheric pressure are specified on a rectangular grid in the same coordinate system and projection as the CMS. The grid is assumed to vary from north to south and west to east so that north-west corner is the grid origin. The spatial extents of the wind/pressure grid must be consistent with the flow grid.
CMS-Flow cards related to wind
| Card | Arguments | Type |
|---|---|---|
| WIND_OUT_TIMES_LIST | Id number of output times list | integer |
| WIND_DRAG_COEFFICIENT | kappa in Hsu (1988) (default 0.4) | real |
| WIND_INPUT_CURVE | Name of model parameter file followed wind curve path | character |
| ANEMOMETER_HEIGHT | Height of wind speeds | meter |
| WIND_PRESSURE_SINGLE_FILE | Name of fleet wind and pressure file | character |
| WIND_PRESSURE_GRID_PARAM | Nwlat,Nwlon,wLatMax,wLonMin,wLatInc,wLonInc | integer and real |
| WIND_PRESSURE_TIME_INCREMENT | wTimeInc | real |