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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. 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 #

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• .
• 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
Code Block
# START OF HEADER # This file is created by Deltares # Additional commments # General part: t_ref = 19991026.000000 # Reference time t_ref_unit = ModifiedJulianDate # Unit used for reference time t_unit = min # Time unit (sec, min, hrs, etc.) #t_unit = hrs # Version of meteo input file, to check if the newest file format is used filetype = meteo_on_flow_grid missing_value = -999.000 # Type of 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 # Value used for undefined or missing data # For Pseudo ArcInfo or Spiderweb wind: n_cols = 400 # Value used for undefined or missing data n_quantity = 3 # Number of columns used for wind datafield n_rows = 16 # Number of quantities prescribed in the file quantity1 = x_wind # Number of rows used for wind datafield grid_unit = # degreeName of quantity1 quantity2 = y_wind # Unit of distances on the grid in both x- and y-direction #grid_unit # Name of =quantity2 quantity3 m = #air_pressure Only for Pseudo ArcInfo wind: x0 = -12.000 # Name of quantity3 unit1 = m s-1 # Xcoordinate of starting point of grid (in units specified in grid_unit) y0 = 48.000 # Unit of quantity1 unit2 = m s-1 # Ycoordinate of starting point of grid (in units specified in grid_unit) value_pos = centre # Unit of quantity2 unit3 = mbar # Location where the data is specified in a cell (centre or corner) #value_pos = corner # Unit of quantity3 ### END OF HEADER TIME = 0 minutes dx since 2008-01-08 00:00:00 +00:00 = 0.12500 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 -9.9900000E+02 -9.9900000E+02 -8.6049000E+00 # Grid dimensions: dx and dy (in units specified in grid_unit) dy = 0.083333333 n_quantity = 3 -1.0240000E+01 -5.4150000E+00 -1.8900000E+00 -2.9040000E+00 -9.9900000E+02 -9.9900000E+02 -9.9900000E+02 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 -1.0000000E+01 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 1.0000000E+03 TIME = 660 minutes since 2008-01-08 00:00:00 +00:00 # NumberFixed offormat: quantities<time> prescribed<time inunit> the file quantity "since" <date> <time> <time zone> =0.0000000E+00 x_wind0.0000000E+00 0.0000000E+00 0.0000000E+00 y_wind0.0000000E+00 0.0000000E+00 -9.9900000E+02 -9.9900000E+02 -2.3290000E+00 -9.0440000E+00 -1.3230000E+01 -8.3310000E+00 -6.9210000E+00 -9.9900000E+02 -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

• 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

### START OF HEADER ### This file is created by Deltares ### All text on a line behind the first # is parsed as commentary ### Additional commments FileVersionair_pressure # Names of the quantities unit = m s-1 m s-1 Pa # Units of the quantities # Only for Spiderweb wind: radius = 600000.00 # Radius of spiderweb (in units specified in rad_unit) rad_unit = m 1.02 # UnitVersion of radius n_quantity = 3 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 # Number of quantities= prescribed in the file quantity1 -9999.000 = wind_speed # Value used for undefined or missing data n_cols # Name of quantity1 quantity2 = wind_from_direction400 # Name of quantity2 quantity3 = p_drop # Number of columns used for wind datafield n_rows = 16 # Name of quantity3 unit1 = m s-1 # Number of rows used for wind datafield grid_unit = degree # Unit of quantity1 unit2 = degree # Unit of distances on the grid in both x- and y-direction: m or degree x_llcorner = -12.000 # Unit of quantity2 unit3 = Pa # Xcoordinate of lower left corner of grid (in units specified in grid_unit) y_llcorner = 48.000 # Unit of quantity3 # Only for wind on a separate curvi-linear grid: grid_file = hirlam.grd # Ycoordinate of lower left corner of grid (in units specified in grid_unit) value_pos = #centre Separate (curvi-linear) grid on which the wind can be specified first_row = nmax # Coordinates given in centre or corner of lower left cell? dx # These four parameters= determine the order in which the data last_row0.12500 = 1 # Grid dimensions: dx and dy (in units specified in grid_unit) dy # is read from= the separate wind file0.083333333 In this way, data which is first_col = 1 n_quantity = 1 # supplied in a reversed order, can also be read. last_col = mmax n_quantity = 1 # Number of quantities prescribed in the file quantity1 = x_wind # Number of quantities prescribed in the file quantity1 = air_pressure # Name of quantity1 (x_wind, y_wind or air_pressure) unit1 = m s-1 # Name of quantity1 unit = Pa # Unit of quantity1 (m s-1 for velocities or Pa/mbar for air_pressure) ### END OF HEADER TIME = 0 minutes since # Unit of quantity1 # END OF HEADER TIME = 0.0000000E+002007-10-08 15:24:00 -02:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 # Time where1.388999 first dataset is supplied # Only for Spiderweb1.388999 wind (every TIME input): x_eye 1.388999 1.388999 = 1152.4388999 2.388999 2.388999 2.388999 2.388999 2.388999 2.388999 # Xcoordinate of2.388999 cyclone eye (Spiderweb centre) at specified TIME y_eye2.388999 2.388999 = 18.9 3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 # Ycoordinate3.388999 of cyclone eye (Spiderweb centre) at specified3.388999 TIME p_drop_eye =3.388999 5300 TIME = 1440 minutes since 2007-10-08 15:24:00 -02:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 2.435253 #2.435253 Pressure drop at cyclone eye (Spiderweb centre) at specified TIME # Actual data field 5.435253 1.388999435253 13.388999435253 14.388999435253 12.388999435253 12.388999557653 12.388999412253 12.388999435255 1.388999435253 12.388999435253 1.388999435253 1552.0000435253 3461.2500435253 3572.5000435253 81.750000435253 201.00000435253 312.25000435253 421.50000435251 534.75000435253 654.00000435253 761.25000 435253 5300.000 5300.0003.355253 53003.000456253 53005.000425253 53001.000223453 5300.000 5300.000 5.523341 53005.000521246 53003.000255258 5300.000 TIME = 1440 # Time where next dataset is supplied # Only for Spiderweb wind (every TIME input):

• 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.

Image Added
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 x_eye = 114.4000 # Version of meteo input file, to check if the newest file format is used filetype # Xcoordinate of cyclone eye (Spiderweb centre)= at specified TIME y_eye meteo_on_curvilinear_grid = 18.90000 # Type of meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value = -999.999 # Ycoordinate of cyclone eye (Spiderweb centre) at specified TIME p_drop_eye = 5300.000 # Value used for undefined or missing data grid_file = hirlam.grd # Pressure drop at cyclone eye (Spiderweb centre) at specified TIME # Actual data field 2.435253 # 2.435253 2.435253 Separate (curvi-linear) grid on which the wind can be specified first_data_value = 2.435253grid_llcorner 2.435253 2.435253 2.435253 2.435253 2.435253 # Options: 2.435253 65.01978grid_llcorner, grid_ul_corner, grid_lrcorner or grid_urcorner data_row 75.11859 = grid_row 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 # Options: grid_row or grid_col. For switching rows and columns. n_quantity = 1 # Number of quantities prescribed in the file quantity1 = x_wind # Name of quantity1 (x_wind, y_wind, air_pressure, relative_humidity, air_temperature or cloudiness) unit1 = m s-1 # Unit of quantity1 (m s-1 for velocities, Pa/ mbar for air_pressure, % for relative_humidity or cloudiness and Celcius for air_temperature) ### END OF HEADER TIME = 0 hours since 2006-01-01 00:00:00 -06:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 101530.000 101300.000 101600.000 101550.000 101500.000 101300.000 1013300.000 101400.000 101430.000 101500.000 101130.000 101320.000 101260.000 101620.000 1013400.000 101520.000 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 101721.314 101811.152 1013410.400 101323.214 101430.000 101500.000 101130.000 101320.000 101260.000 101620.000 1013400.000 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.

Image Added
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.