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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: filetype = Spiderweb # Type of meteo input file: Curvi-linear, Pseudo ArcInfo or Spiderweb meteo_time_zone = -3.0 # Time zone, indicating the time difference with GMT+0 (in hours) ref_time = 19991026.000000 # Reference time ref_time_unit = ModifiedJulianDay # Version of meteo input file, to check if the newest file format is used filetype = # Unit used for reference time time_unit meteo_on_flow_grid = min # 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 # Time unit (s, min, hrs, etc.) #time_unit = hrs # Value used for undefined or missing data n_quantity = 3 NODATA_value = -999.000 # Number of quantities prescribed #in Valuethe usedfile quantity1 for undefined or missing data ### For Pseudo= ArcInfo or Spiderweb x_wind: n_cols = 400 # Name of quantity1 quantity2 = y_wind # Number of columns used for wind datafield n_rows = 16 # Name of quantity2 quantity3 = air_pressure # Number of rows used for wind datafield grid_unit = degree # Name of quantity3 unit1 = m s-1 # Unit of distances on the grid in both x- and y-direction #grid_unit = m ### Only for# PseudoUnit ArcInfoof wind:quantity1 #x0unit2 = =m s-1 -12.000 # XcoordinateUnit of quantity2 unit3 starting point of grid (in units specified in grid_unit) #y0 = mbar = 48.000 # Unit of quantity3 ### END OF HEADER TIME = # Ycoordinate of0 startingminutes point of grid (in units specified in grid_unit) #value_possince 2008-01-08 00:00:00 +00:00 = centre # 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 # Location where the data is specified in a cell (centre or corner) ##value_pos = corner #dx = 0.12500 -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 # Grid dimensions: dx and dy (in units specified in grid_unit) #dy # Fixed format: <time> <time unit> "since" <date> <time> <time zone> = 0.0833333330000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+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 #n_quantity -1.0000000E+01 -1.1000000E+01 =-1.2000000E+01 -1.5000000E+01 3-1.8000000E+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 # Number of quantities prescribed in the file #quantity1 1.0200000E+03 1.0160000E+03 1.0140000E+03 = 1.0110000E+03 x_wind 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 FileVersion = 1.02 # Name of quantity1 #quantity2 = y_wind # NameVersion of quantity2 #quantity3meteo input file, to check if the =newest file format air_pressureis used filetype = meteo_on_equidistant_grid # NameType of quantity3 #unit1meteo input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value = m s-1-9999.000 # Value used for #undefined Unitor ofmissing quantity1data #unit2n_cols = 400 m s-1 # UnitNumber of quantity2 #unit3columns used for wind datafield n_rows = Pa16 # UnitNumber of quantity3 ###rows Onlyused for Spiderweb wind: datafield spwgrid_radiusunit = degree 600000.00 # RadiusUnit of spiderweb (distances on the grid in unitsboth specifiedx- in rad_unit) spw_rad_unit =and y-direction: m or degree x_llcorner m = -12.000 # UnitXcoordinate of radius n_quantity = 3lower left corner of grid (in units specified in grid_unit) y_llcorner = 48.000 # Number of quantities prescribed# inYcoordinate theof file quantity1lower left corner of grid (in units =specified wind_speedin grid_unit) value_pos = centre # Name of quantity1 quantity2 = wind_from_direction # Coordinates given in centre or corner of lower left cell? dx = 0.12500 # Name of quantity2 quantity3 = p_drop # Grid dimensions: dx and dy (in units specified in grid_unit) dy # Name of quantity3 unit1 = m s-10.083333333 n_quantity #= Unit of quantity1 unit2 1 = degree # Number of quantities prescribed in # Unit of quantity2 unit3the file quantity1 = Pa x_wind # UnitName of quantity3 ### Only for wind on a separate curvi-linear grid: #grid_filequantity1 (x_wind, y_wind or air_pressure) unit1 = hirlam.grd = m s-1 # Separate (curvi-linear) grid on which the wind can be specified #first_row # Unit of quantity1 (m s-1 =for velocities or Pa/mbar nmax for air_pressure) ### END OF HEADER TIME = 0 minutes since 2007-10-08 15:24:00 -02:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> # These1.388999 four parameters determine the order in which1.388999 the data #last_row 1.388999 = 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 2.388999 # is read from2.388999 the separate wind file. In this way,2.388999 data which is #first_col 2.388999 = 2.388999 1 2.388999 2.388999 2.388999 2.388999 2.388999 3.388999 3.388999 # supplied in3.388999 a reversed order, can also be read. #last_col3.388999 3.388999 = mmax #n_quantity 3.388999 = 3.388999 1 3.388999 3.388999 3.388999 TIME = 1440 minutes since 2007-10-08 15:24:00 -02:00 # NumberFixed offormat: quantities<time> prescribed<time inunit> the file #quantity1 ="since" <date> <time> <time zone> 2.435253 air_pressure 2.435253 5.435253 1.435253 3.435253 4.435253 2.435253 # Name of quantity1 #unit1 2.557653 2.412253 = 2.435255 Pa 1.435253 2.435253 1.435253 2.435253 1.435253 2.435253 1.435253 # Unit of quantity1 ### END OF HEADER TIME 1.435253 2.435253 1.435251 = 0.0000000E+004.435253 4.435253 1.435253 3.355253 3.456253 5.425253 # Time where first dataset is supplied x_spw_eye1.223453 5.523341 = 1155.4521246 3.255258 # 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

• 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 # Version of meteo #input Pressurefile, dropto atcheck cycloneif eyethe (Spiderwebnewest centre)file atformat specifiedis TIMEused filetype 1.388999 1.388999= meteo_on_curvilinear_grid 1.388999 1.388999 1.388999 1.388999 # Type of meteo 1.388999input file: meteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value 1.388999 = 1-999.388999999 1.388999 155.0000 346.2500 357.5000 8.750000 20.00000 # Value used 31.25000for undefined or missing data grid_file 42.50000 = 53hirlam.75000grd 65.00000 76.25000 5300.000 5300.000 5300.000 5300.000# Separate (curvi-linear) grid on which the 5300.000wind can be specified first_data_value = 5300.000 grid_llcorner 5300.000 5300.000 5300.000 5300.000 TIME # Options: grid_llcorner, =grid_ul_corner, grid_lrcorner or grid_urcorner data_row 1440= grid_row # Time where next dataset is supplied x_spw_eyeOptions: grid_row or grid_col. For switching rows and columns. n_quantity = 114.40001 # Xcoordinate of cyclone eye (Spiderweb centre) at specified TIME y_spw_eye # Number of quantities prescribed in the file quantity1 = x_wind 18.90000 # YcoordinateName of cyclone eyequantity1 (Spiderweb centre) at specified TIME x_wind, y_wind, air_pressure, relative_humidity, air_temperature or cloudiness) unit1 p_drop_spw_eye = = 5300.000 m s-1 # Pressure drop at cyclone eye# (SpiderwebUnit centre)of atquantity1 specified TIME 2.435253 2.435253 2.435253 (m s-1 for velocities, Pa/ mbar for air_pressure, % for relative_humidity or cloudiness and Celcius for air_temperature) ### END OF HEADER TIME 2.435253 2.435253 = 2.4352530 hours since 2006-01-01 00:00:00 -06:00 2.435253 # Fixed format: <time> 2.435253<time unit> "since" <date> <time> <time zone> 2 101530.435253000 2101300.435253000 65101600.01978000 75101550.11859000 85101500.25320000 95101300.45370000 1051013300.7529000 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 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.