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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. 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 |
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### 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 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 startingquantity2 unit3 point of grid (in units specified in grid_unit) #y0 = mbar = 48.000 # Unit of quantity3 ### END OF HEADER TIME #= Ycoordinate of starting0 pointminutes 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 -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 # 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 -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 |
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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 # Location where the data is specified in a cell (centre or corner) ##value_pos = corner #dx = 0.12500 # Grid dimensions: dx and dy (in units specified in grid_unit) #dy = 0.083333333 #n_quantity = 3 # Number of quantities prescribed in the file #quantity1 = x_wind # 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 = m400 s-1 # UnitNumber of quantity2 #unit3columns used for wind datafield n_rows = Pa16 # UnitNumber of quantity3 ###rows Onlyused for Spiderweb wind: datafield spwgrid_radiusunit = 600000.00degree # 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 = 3 lower left corner of grid (in units specified in grid_unit) y_llcorner = 48.000 # NumberYcoordinate of quantities prescribed in the file quantity1lower left corner of grid (in units specified in grid_unit) value_pos = wind_speedcentre # Name of quantity1 quantity2 # Coordinates given in centre or =corner of lower wind_from_directionleft cell? dx = 0.12500 # Name of quantity2 quantity3 = p_drop # Grid dimensions: dx and dy (in units specified in grid_unit) dy = # Name0.083333333 of quantity3 unit1 = m s-1 n_quantity = 1 # Unit of quantity1 unit2 = degree # Number of quantities prescribed in the file quantity1 = x_wind # Unit of quantity2 unit3 = Pa # Name of quantity1 (x_wind, y_wind or air_pressure) unit1 = m s-1 # Unit of quantity3 ### Only for wind on a separate curvi-linear grid: #grid_file = hirlam.grd # Unit of quantity1 (m s-1 for velocities or Pa/mbar for air_pressure) ### END OF HEADER TIME # Separate (curvi-linear) grid on which= the wind can0 be specified #first_row minutes since 2007-10-08 15:24:00 -02:00 = nmax # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 1.388999 1.388999 1.388999 1.388999 1.388999 # These1.388999 four parameters determine the order in which the data #last_row1.388999 1.388999 = 1.388999 1.388999 2.388999 2.388999 2.388999 2.388999 2.388999 2.388999 # is read from the separate wind file. In this way, data which is #first_col 2.388999 2.388999 =2.388999 1 2.388999 3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 # supplied in a reversed3.388999 order, can also be read. #last_col 3.388999 = 3.388999 mmax #n_quantityTIME = 1 = 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 5.435253 # Number1.435253 of quantities prescribed in the file #quantity1 3.435253 =4.435253 air_pressure 2.435253 2.557653 2.412253 2.435255 1.435253 2.435253 # Name of quantity1 #unit1 1.435253 2.435253 = Pa1.435253 2.435253 1.435253 1.435253 2.435253 1.435251 4.435253 4.435253 # Unit of quantity1 ### END OF HEADER TIME 1.435253 3.355253 = 0.0000000E+003.456253 5.425253 1.223453 5.523341 5.521246 # Time where first dataset is supplied 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 3.255258 |
- 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 |
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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 # Pressure drop at cyclone eye (Spiderweb centre) at specified TIME 1.388999 1.388999 # 1.388999Version of meteo input file, to check 1.388999if the newest file format is used filetype 1.388999 1.388999 = 1.388999meteo_on_curvilinear_grid 1.388999 1.388999 1.388999 # 155.0000Type of meteo input file: meteo_on_flow_grid, 346.2500 meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value 357.5000= -999.999 8.750000 20.00000 31.25000 42.50000 53.75000 65.00000 # 76.25000Value used for undefined or 5300.000 missing data grid_file 5300.000 = 5300hirlam.000grd 5300.000 5300.000 5300.000 5300.000 5300.000 5300.000# Separate (curvi-linear) grid on which the 5300.000wind can be TIME specified first_data_value = grid_llcorner = 1440 # Options: grid_llcorner, grid_ul_corner, grid_lrcorner or grid_urcorner data_row = #grid_row Time where next dataset is supplied x_spw_eye = 114.4000 # Options: grid_row or grid_col. For switching rows and columns. n_quantity = # Xcoordinate of cyclone1 eye (Spiderweb centre) at specified TIME y_spw_eye = 18.90000 # Number of quantities prescribed in the file quantity1 # Ycoordinate of cyclone eye= (Spiderweb centre) at specifiedx_wind TIME p_drop_spw_eye = 5300.000 # Name of quantity1 (x_wind, y_wind, air_pressure, relative_humidity, air_temperature or cloudiness) unit1 # Pressure drop at cyclone eye (Spiderweb centre)= at specified TIME 2.435253m s-1 2.435253 2.435253 2.435253 2.435253 2.435253 2.435253 # Unit 2.435253of quantity1 (m s-1 for velocities, Pa/ 2.435253mbar for air_pressure, % for relative_humidity or 2.435253cloudiness and Celcius for air_temperature) 65.01978 ### END OF HEADER TIME 75.11859 85.25320= 0 hours since 2006-01-01 00:00:00 -06:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 101530.000 95101300.45370000 105101600.7529000 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 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 |
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first_data_value = grid_ll_corner
data_row = grid_column
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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 |
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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_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.