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input files containing meteorological time series such as wind velocity, air pressure, air temperature. |
Space varying wind and pressure input files (meteofiles)
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At present, for different wind meteo input files, different headers are used, which are read in different ways in the sourcecodesource code. Some effeort effort has been put to in making the files more self-descriptive, readible readable and to make the input of the different files more consistent. For three four wind-input options, a suggestion to standardise the headers is shown below. The suggestion is conform the a possible transition to NetCDF format in the future. See NetCDF standard names for more information on the used standard NetCDF names. Further below (in section: Integrated standardisation), an integrated file format is proposed which can be used for all wind input options. For meteo on the FLOW grid, meteo on an equidistant (rectilinear or spherical) grid, meteo on a separate curvilinear grid and meteo on a Spiderweb grid, examples of input files are shown below.
- Keywords are case INsensitive.
- Comments are indicated by a #
...
- .
- The keyword FileVersion (= 1.02) must be the first keyword, the order of the other keywords is free to choose.
- The pressure correction on boundaries using Paver and Pcorr, which used to be prescribed in the air pressure meteo file, has been moved to the MD-File. The correction is specified using the keyword:
PavBnd (P average on Boundaries). This average pressure is applied on all boundaries to reduce pressure gradients there. The average pressure needs to be specified in Pascals.
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- Meteo on the FLOW grid:
For meteo on the FLOW grid, the wind velocities and air pressure are specified in 1 file, using the keyword:
Filwnd
| Code Block |
|---|
### START OF HEADER
### This file is created by Deltares
FileVersion = 1.02 |
- The Pseudo ArcInfo wind input file, with keyword in MD-file Filwp
| Code Block |
|---|
# START OF HEADER # This file is created by Deltares n_cols = 201 n_rows = 173 x0 = -12.000 y0 = 48.000 value_pos = centre #value_pos = corner cellsize = 0.12500 0.083333333 x_unit = degree #x_unit = m t_ref = 20080312.000000 t_ref_unit = ModifiedJulianDate t_unit = hrs #t_unit = # Version ModifiedJulianDate n_quantityof meteo input file, to =check if the newest 3 quantityfile format is used filetype = x_wind= y_windmeteo_on_flow_grid air_pressure unit = m s-1 m s-1 Pa missing_value = # Type -999.000 # END OF HEADER TIMEof meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value = -9.9900000E+02 = 0.0 1000.776001 1000.687927 1000.599976 1000.512024 1000.423950 1000.334961 1000.245911 1000.156921 1000.067932 TIME = 120.0 1000.786001 1000.637927 1000.579976 1000.582024 1000.424950 1000.324961 1000.265911 1000.159921 1000.060932 |
- The wind on a curvi-linear grid input file, with keyword in MD-file Fwndgp
| Code Block |
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# START OF HEADER # This file is created by Deltares grid_file = hirlam.grd first_row # Value used for undefined or missing data n_quantity = 3 = nmax last_row = 1 first_col = 1 last_col = mmax t_ref # Number of quantities prescribed in the =file quantity1 20080312.000000 t_ref_unit = ModifiedJulianDate tx_unitwind = hrs n_quantity = 1 quantity = air_pressure unit = # Name Pa missing_valueof quantity1 quantity2 = -999.0 # END OF HEADER TIME = y_wind = 2130 101894.125 101880.625 101867.125 101853.625 101840.625 101827.125 101813.125 101798.625 101784.625 101769.625 101754.125 101739.125 101723.625 TIME = 2273.0 100038.75 100037.25 100035.75 100035.25 100035.25 100035.25 100036.5 100038.0 100039.75 100042.25 100045.0 100048.0 100052.0 100056.0 100060.0 |
- The Spiderweb wind input file, with keyword in MD-file Filweb
| Code Block |
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# START OF HEADER # This file is created by Deltares # Spiders web derived from TRACK file: 19991026_0000.imd # Wind direction winddir = where it blows from, degrees from true north n_cols # Name of quantity2 quantity3 = air_pressure = # Name of 400quantity3 n_rowsunit1 = = 16 radius m s-1 = 600000.00 rad_unit = m x_unit = degree #x_unit = m t_ref# Unit of quantity1 unit2 = 19991026.000000 t_ref_unit= =m s-1 ModifiedJulianDate t_unit = min #t_unit = hrs n_quantity = 3 quantity # Unit of quantity2 unit3 = wind_speed wind_from_direction= mbar p_drop unit = m s-1 degree Pa missing_value = # Unit of -999.000 #quantity3 ### END OF HEADER TIME = 0 minutes since = 0.0000000E+00 x02008-01-08 00:00:00 +00:00 = 115.4 y0 # Fixed format: <time> <time unit> "since" <date> <time> =<time zone> 18.9 p_drop_eye 0.0000000E+00 = 0.0000000E+00 -5300 1.3889990.0000000E+00 0.0000000E+00 1.3889990.0000000E+00 0.0000000E+00 -9.9900000E+02 1.388999-9.9900000E+02 -8.6049000E+00 -1.3889990240000E+01 -5.4150000E+00 -1.3889998900000E+00 -2.9040000E+00 -9.9900000E+02 1.388999-9.9900000E+02 -9.9900000E+02 -1.3889990000000E+01 -1.0000000E+01 -1.0000000E+01 -1.3889990000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.3889990000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.3889990000000E+01 -1.0000000E+01 155.0000 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 3461.25000000000E+03 1.0000000E+03 357.50001.0000000E+03 1.0000000E+03 8.7500001.0000000E+03 1.0000000E+03 20.000001.0000000E+03 1.0000000E+03 311.250000000000E+03 1.0000000E+03 42.500001.0000000E+03 1.0000000E+03 53.750001.0000000E+03 1.0000000E+03 65.000001.0000000E+03 76.250001.0000000E+03 TIME = 5300.000660 minutes since 2008-01-08 00:00:00 +00:00 5300.000 5300.000 5300.000 # Fixed format: <time> 5300.000<time unit> "since" <date> <time> <time 5300.000zone> 0.0000000E+00 53000.0000000000E+00 0.0000000E+00 5300.0000.0000000E+00 0.0000000E+00 5300.0000.0000000E+00 -9.9900000E+02 5300.000-9.9900000E+02 TIME -2.3290000E+00 -9.0440000E+00 -1.3230000E+01 -8.3310000E+00 -6.9210000E+00 = -9.9900000E+02 1440 x0 = 114.4000 y0 = 18.90000 p_drop_eye = -5300.000 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 65.01978 75.11859 85.25320 95.45370 105.7529 116.1833 126.7762 137.5612 148.5649 159.8090 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 |
Integrated standardisation
An integrated file format, suitable for all wind input, might look as follows:
-9.9900000E+02 -9.9900000E+02
-1.0000000E+01 -1.1000000E+01 -1.2000000E+01 -1.5000000E+01 -1.8000000E+01 -1.4000000E+01 -1.2000000E+01 -0.8000000E+01
-1.2000000E+01 -1.6000000E+01 -1.2000000E+01 -1.0000000E+01 -0.7000000E+01 -0.4000000E+01 0.0000000E+00 -0.3000000E+01
1.0130000E+03 1.0140000E+03 1.0140000E+03 1.0160000E+03 1.0120000E+03 1.0120000E+03 1.0180000E+03 1.0200000E+03
1.0160000E+03 1.0140000E+03 1.0110000E+03 1.0130000E+03 1.0110000E+03 1.0180000E+03 1.0150000E+03 1.0130000E+03
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- Meteo on an equidistant grid:
For meteo on an equidistant grid, the wind velocities and air pressure are specified in 3 separate files using the keywords:
Filwu
Filwv
Filwp
and Filwr, Filwt, Filwc for relative humidity, air temperature and cloudiness respectively.
| Code Block |
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### START OF HEADER
### This file is created by Deltares
### All text on a line behind the first # is parsed as commentary
### Additional commments
FileVersion = 1.02 # Version of meteo input file, to check if the newest file format is used
filetype = meteo_on_equidistant_grid # Type of meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid
NODATA_value = -9999.000 |
| Code Block |
# START OF HEADER # This file is created by Deltares # Additional commments # General part: t_ref = 19991026.000000 # Value used for undefined #or Referencemissing timedata tn_ref_unitcols = ModifiedJulianDate = 400 # Unit used for reference time t_unit = min # Number of columns used for wind datafield n_rows = 16 # Time unit (sec, min, hrs, etc.) #t_unit = hrs # Number of rows used for wind datafield grid_unit = degree missing_value = -999.000 # Unit of distances on the grid in #both Valuex- used for undefinedand y-direction: m or missing data # For Pseudo ArcInfo or Spiderweb wind: n_colsdegree x_llcorner = 400-12.000 # Xcoordinate of lower #left Numbercorner of columnsgrid used(in forunits wind datafield n_rows specified in grid_unit) y_llcorner = 16 48.000 # Ycoordinate of lower #left Numbercorner of grid rows(in usedunits forspecified wind datafield x_unitin grid_unit) value_pos = degreecentre # UnitCoordinates ofgiven distancesin oncentre the grid #x_unit or corner of lower left cell? dx = m = # Only for Pseudo0.12500 ArcInfo wind: x0 = -12.000 # XcoordinateGrid ofdimensions: startingdx pointand ofdy grid (in units specified in xgrid_unit) y0dy = 480.000083333333 n_quantity # Ycoordinate of starting= point of grid (in1 units specified in x_unit) value_pos = centre # Number of quantities prescribed in the file quantity1 # Location where the data is specified in a= cell (centre or corner) #value_posx_wind = corner cell_size = 0.12500# Name of quantity1 (x_wind, y_wind 0.083333333or air_pressure) unit1 = m s-1 # Grid dimensions: dx and dy (in units specified in x_unit) n_quantity = 3 # Unit of quantity1 (m s-1 for velocities or Pa/mbar for air_pressure) ### END OF HEADER TIME = 0 minutes # Number of quantities prescribed in the file quantitysince 2007-10-08 15:24:00 -02:00 # =Fixed format: <time> <time x_wind y_windunit> "since" <date> <time> <time zone> 1.388999 1.388999 air_pressure 1.388999 # Names1.388999 of the quantities unit 1.388999 1.388999 = m s-1.388999 1.388999 m s-1 1.388999 Pa1.388999 2.388999 2.388999 #2.388999 Units of the quantities # Only for Spiderweb2.388999 wind: radius 2.388999 = 6000002.00388999 2.388999 2.388999 2.388999 2.388999 3.388999 3.388999 # Radius of spiderweb (in units3.388999 specified in rad_unit) rad_unit 3.388999 = m3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 TIME #= Unit of radius n_quantity =1440 minutes since 2007-10-08 15:24:00 -02:00 3 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 2.435253 2.435253 5.435253 1.435253 3.435253 4.435253 # Number of quantities prescribed in the file quantity2.435253 2.557653 = wind_speed wind_from_direction2.412253 p_drop 2.435255 1.435253 # Names of the quantities unit 2.435253 1.435253 = m s-12.435253 1.435253 degree 2.435253 1.435253 Pa 1.435253 2.435253 # Units of1.435251 the quantities # Only for wind4.435253 on a separate curvi-linear grid: grid_file 4.435253 = hirlam1.grd435253 3.355253 3.456253 5.425253 1.223453 5.523341 #5.521246 Separate (curvi-linear) grid on which the wind3.255258 can be specified first_row = nmax # These four parameters determine the order in which the data last_row = 1 # is read from the separate wind file. In this way, data which is first_col = 1 |
- Explanation of the data to grid conversion for meteo on an equidistant grid
For meteo on an equidistant grid the orientation of the data is the same as the grid (visually). The first data value is thus located at the grid at (1,nmax). A line is then read as a row on the grid and the second line in the dataset is row nmax-1 on the grid. See also figure 1.
Figure 1: Data to grid conversion for meteo on an equidistant grid.
- Meteo on a separate curvilinear grid:
For meteo on a separate curvilinear grid, the wind velocities and air pressure are specified in 3 separate files using the keywords:
Fwndgu
Fwndgv
Fwndgp
and Fwndgr, Fwndgt, Fwndgc for relative humidity, air temperature and cloudiness respectively.
| Code Block |
|---|
### START OF HEADER ### This file is created by Deltares ### All text on a line behind the first # is parsed as commentary ### Additional commments FileVersion = 1.02 # supplied in a reversed order, can also be read. last_col = # Version mmax n_quantity = 1 of meteo input file, to check if the newest file format is used filetype = meteo_on_curvilinear_grid # Type of meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, # Number of quantities prescribed in the file quantitymeteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value = -999.999 = air_pressure # Value used #for Namesundefined ofor themissing quantitiesdata unitgrid_file = = hirlam.grd Pa # Separate (curvi-linear) grid on which the wind can be specified first_data_value = # Units of the quantities # END OF HEADER TIMEgrid_llcorner = 0.0000000E+00 # Options: grid_llcorner, grid_ul_corner, grid_lrcorner or grid_urcorner data_row = #grid_row Time where first dataset is supplied # Only for Spiderweb wind (every TIME input): x0 = 115.4 # Options: grid_row or grid_col. For switching rows and columns. n_quantity = 1 # Xcoordinate of cyclone eye (Spiderweb centre) at current TIME y0 = 18.9 # Number of quantities prescribed in the file quantity1 = x_wind # Ycoordinate of cyclone eye (Spiderweb centre) at current TIME p_drop_eye = 5300 # Name of quantity1 (x_wind, y_wind, air_pressure, relative_humidity, air_temperature or cloudiness) unit1 = m s-1 # Pressure drop at cyclone eye (Spiderweb centre) at current TIME # Actual data field 1.388999 1.388999 1.388999 # Unit of 1.388999quantity1 (m s-1 for velocities, Pa/ mbar 1.388999 1.388999 for air_pressure, % for relative_humidity or cloudiness and Celcius for air_temperature) ### END OF HEADER TIME 1.388999 1.388999 = 0 1.388999hours since 2006-01-01 00:00:00 -06:00 1.388999 155.0000 # Fixed format: <time> 346.2500<time unit> "since" <date> <time> <time zone> 357 101530.5000000 8101300.750000000 20101600.00000000 31101550.25000000 42101500.50000000 53101300.75000000 651013300.00000000 76.25000 5300.101400.000 5300 101430.000 5300101500.000 5300101130.000 5300101320.000 5300101260.000 5300101620.000 53001013400.000 5300101520.000 5300.000 TIME TIME = 1440 hours since 2006-01-01 00:00:00 -06:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 101298.544 102108.102 101998.521 101928.544 # Time where next dataset is supplied x0101721.314 101811.152 1013410.400 = 114.4000 101323.214 101430.000 101500.000 101130.000 101320.000 101260.000 101620.000 #1013400.000 Xcoordinate of cyclone eye (Spiderweb centre) at current TIME y0 = 18.90000 # Ycoordinate of cyclone eye (Spiderweb centre) at current TIME p_drop_eye = 5300.000 # Pressure drop at cyclone eye (Spiderweb centre) at current TIME 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 65.01978 75.11859 85.25320 95.45370 105.7529 116.1833 126.7762 137.5612 148.5649 159.8090 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 101520.000 |
- Explanation of the data to grid conversion for wind on a separate curvilinear grid.
The first_data_value keyword is used to determine the starting point on the grid. The first_data_value is the first value that is read in the meteo file, i.e. the upper left value in a data block. The keyword has 4 possible values:
grid_llcorner, meaning m = 1, n = 1 (on the curvilinear grid)
grid_lrcorner, meaning m = mmax, n = 1 ( " )
grid_ulcorner, meaning m = 1, n = nmax ( " )
grid_urcorner, meaning m = mmax, n = nmax ( " )
The data_row keyword is then used to determine the direction of placing the data on the grid, i.e. data_row = grid_column means that a row that is read in the meteo file becomes a column in the array on the grid (so fixed m, increasing n).
Example:
| Code Block |
|---|
first_data_value = grid_ll_corner
data_row = grid_column
|
means:
The first read value (top left) of the meteofile coincides with the point (1,1) on the grid. The first row in the meteofile is then the first column on the grid, i.e. (1,1:nmax). The second row is then the second column (2,1:nmax) and so on. See also Figure 2.
Figure 2: Data to grid conversion for wind on a separate curvilinear grid.
- Meteo on a Spiderweb grid:
For meteo on a Spiderweb grid, the wind velocities and air pressure are specified in 1 file using the keyword:
Filweb
Meteo on a Spiderweb grid can be added to one of the other wind formats. Near and in the cyclone the winds are added using an averaging algorithm.
| Code Block |
|---|
### START OF HEADER
### This file is created by Deltares
### All text on a line behind the first # is parsed as commentary
### Additional commments
FileVersion = 1.02 # Version of meteo input file, to check if the newest file format is used
filetype = meteo_on_spiderweb_grid # Type of meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid
NODATA_value = -999.000 # Value used for undefined or missing data
n_cols = 16 # Number of columns used for wind datafield
n_rows = 400 # Number of rows used for wind datafield
spw_radius = 600000.00 # Radius of spiderweb (in units specified in rad_unit)
spw_rad_unit = m # Unit of radius
n_quantity = 3 # Number of quantities prescribed in the file
quantity1 = wind_speed # Name of quantity1
quantity2 = wind_from_direction # Name of quantity2
quantity3 = p_drop # Name of quantity3
unit1 = m s-1 # Unit of quantity1
unit2 = degree # Unit of quantity2
unit3 = Pa # Unit of quantity3
### END OF HEADER
TIME = 0 minutes since 2004-01-03 11:02:00 +01:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone>
x_spw_eye = 115.4 # Xcoordinate of cyclone eye (Spiderweb centre) at specified TIME
y_spw_eye = 18.9 # Ycoordinate of cyclone eye (Spiderweb centre) at specified TIME
p_drop_spw_eye = 5300 # Pressure drop at cyclone eye (Spiderweb centre) at specified TIME
1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999
155.0000 346.2500 357.5000 8.750000 20.00000 31.25000 42.50000 53.75000 65.00000 76.25000
5300.000 5300.000 5300.000 5300.000 5300.000 5300.000 5300.000 5300.000 5300.000 5300.000
TIME = 1440 minutes since 2004-01-03 11:02:00 +01:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone>
x_spw_eye = 114.4000 # Xcoordinate of cyclone eye (Spiderweb centre) at specified TIME
y_spw_eye = 18.90000 # Ycoordinate of cyclone eye (Spiderweb centre) at specified TIME
p_drop_spw_eye = 5300.000 # Pressure drop at cyclone eye (Spiderweb centre) at specified TIME
2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253
65.01978 75.11859 85.25320 95.45370 105.7529 116.1833 126.7762 137.5612 148.5649 159.8090
5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544 5298.544
|
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- Explanation of the grid definition for wind on a Spiderweb grid.
The Spiderweb grid is defined using the number of rows 'n_rows' and the number of columns 'n_cols'.
The number of rows is used to divide the radius of the Spiderweb in small rings of width spw_radius/n_rows [m].
The number of columns is used to divide the circle in parts with angles of 2*pi/n_cols [rad].
The wind direction is defined according to the nautical convention, i.e. wind from the North has direction 0 degrees and the angle increases when turning clockwise.
If the grid_unit is 'degree' than the coordinates of the Spiderweb/cyclone eye are given in spherical coordinates using keywords 'x_spw_eye' and 'y_spw_eye'.
For each time of the time series, the coordinates of the Spiderweb eye and the pressure drop in the eye must be specified.