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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)
Wind input files
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 |
|---|
# This file is created by Deltares ncols = 201 nrows = 173 x0 = -12.000 y0 = 48.000 valuePos = centre #valuePos = corner cellsize = 0.12500 0.083333333 xunit = degree #xunit = m tref = 20080312.000000 tunit = hrs #tunit = ModifiedJulianDate nquantity = 3 quantity# Version of meteo input file, to =check if the newest x_windfile format is used filetype y_wind air_pressure unit = meteo_on_flow_grid = m s-1 m s-1 Pa missing_value = -999.000 TIME # Type of =meteo input file: 0.0 1000.776001 1000.687927 1000.599976 1000.512024 1000.423950 1000.334961 1000.245911 1000.156921 1000.067932 TIMEmeteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value = -9.9900000E+02 = 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 |
|---|
# This file is created by Deltares gridfile =# Value used for hirlam.grd firstrowundefined or missing data n_quantity = = nmax lastrow 3 = 1 firstcol = 1 lastcol = mmax tref = 20080312.000000 tunit # Number of quantities prescribed in the =file quantity1 hrs nquantity = = x_wind 1 quantity = air_pressure unit = Pa missing_value = -999.0 TIME =# Name of 2130quantity1 quantity2 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 = y_wind = 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 |
|---|
# This file is created by Deltares # Spiders web derived from# TRACKName file: 19991026_0000.imd # Wind direction winddirof quantity2 quantity3 = where it blowsair_pressure from, degrees from true north ncols = 400 nrows = 16 radius # Name =of quantity3 unit1 600000.00 radunit = m xunit s-1 = degree #xunit = m tref = 199910260000 tunit # Unit of quantity1 unit2 = min #tunit = m =s-1 hrs nquantity = 3 quantity = wind_speed wind_from_direction air_pressure unit = # Unit of m s-1quantity2 unit3 degree= mbar Pa missing_value = -999.000 TIME = 0.0000000E+00 x0 = # Unit of 115.4quantity3 y0### END OF HEADER TIME = 0 minutes since 2008-01-08 =00:00:00 +00:00 18.9 pdrop = 5300 1.388999 # Fixed format: <time> <time 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 x0 = 114.4000 y0 = 18.90000 pdrop = 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:
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
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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 |
|---|
### 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 # Spiderweb wind file, derived from TRACK file: 19991026_0000.imd # Wind direction winddir = where it blows from, degrees from true north # General part: tref = 199910260000 # Value used for undefined #or Referencemissing time tunitdata n_cols = min400 # TimeNumber of unitcolumns (sec, min, hrs, etc.) #tunitused for wind datafield n_rows = hrs16 nquantity = 3 # Number of rows used for wind datafield grid_unit = degree # Number of quantities prescribed in the file missing_value = -999.000 # Unit of distances on the grid in both x- and y-direction: m or degree x_llcorner = -12.000 # Value used for undefined or no data # Only for wind on a separate curvi-linear grid: gridfile = hirlam.grd # Xcoordinate of lower left corner of grid (in units specified in grid_unit) y_llcorner = 48.000 # Separate (curvi-linear) grid on which the wind can be specified firstrow = nmax # Ycoordinate of lower left corner of grid (in units specified in grid_unit) value_pos = centre # These four parameters determine the order in which the data lastrow = 1 # Coordinates given in centre or corner of lower left cell? dx = 0.12500 # is read from the separate wind file. In this way, data which is firstcol = 1 # Grid dimensions: dx and dy (in units specified in grid_unit) dy = 0.083333333 # supplied in a reversed order, can also be read. lastcol = mmax n_quantity = 1 # quantity = air_pressure # Number of quantities # Names of the quantities unitprescribed in the file quantity1 = Pa x_wind # UnitsName of the quantities # For Pseudo ArcInfo or Spiderweb wind: ncolsquantity1 (x_wind, y_wind or air_pressure) unit1 = 400m s-1 # NumberUnit of columns usedquantity1 (m s-1 for windvelocities datafield nrows or Pa/mbar for air_pressure) ### END OF HEADER TIME = 16 = 0 minutes since 2007-10-08 15:24:00 -02:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 1.388999 1.388999 #1.388999 Number of rows used for wind datafield xunit 1.388999 1.388999 = 1.388999 degree 1.388999 1.388999 1.388999 1.388999 2.388999 2.388999 # Unit2.388999 of distances on the grid #xunit 2.388999 2.388999 = m 2.388999 # Only2.388999 for Pseudo ArcInfo wind: x0 2.388999 2.388999 = -122.000388999 3.388999 3.388999 3.388999 3.388999 3.388999 3.388999 # Xcoordinate of3.388999 starting point of grid (in units specified3.388999 in xunit) y0 3.388999 3.388999 = TIME 48.000 = 1440 minutes since 2007-10-08 15:24:00 -02:00 # Fixed format: <time> <time unit> "since" <date> <time> <time zone> 2.435253 # Ycoordinate2.435253 of starting point of grid (in units5.435253 specified in xunit) valuePos 1.435253 = centre3.435253 4.435253 2.435253 2.557653 2.412253 2.435255 1.435253 # Location2.435253 where the data is specified (centre or corner) #valuePos1.435253 2.435253 = corner 1.435253 2.435253 1.435253 1.435253 cellsize 2.435253 = 01.12500435251 04.083333333435253 4.435253 1.435253 3.355253 # Grid dimensions:3.456253 dx and dy (in units specified5.425253 in xunit) quantity 1.223453 = x_wind 5.523341 y_wind5.521246 air_pressure3.255258 # Names of the quantities unit = m s-1 m s-1 Pa # Units of the quantities # Only for Spiderweb wind: radius = 600000.00 |
- 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 # Radius of spiderweb (in units specified in runit) radunit = m # Version of meteo input file, to check if the newest file format is used filetype = meteo_on_curvilinear_grid # Unit of radius quantity # Type =of meteo input file: wind_speed wind_from_direction air_pressuremeteo_on_flow_grid, meteo_on_equidistant_grid, meteo_on_curvilinear_grid or meteo_on_spiderweb_grid NODATA_value #= Names of the quantities unit-999.999 = m s-1 degree Pa # Value used for undefined or missing data grid_file # Units of the= quantities # End of headerhirlam.grd TIME = 0.0000000E+00 # Separate (curvi-linear) grid on which the wind can be specified first_data_value = grid_llcorner # Time where first dataset is supplied # Only for Spiderweb wind (every TIME input): x0 # Options: grid_llcorner, grid_ul_corner, grid_lrcorner or grid_urcorner data_row = 115.4 = grid_row # Xcoordinate of cyclone# eye (Spiderweb centre) at current TIME y0 Options: grid_row or grid_col. For switching rows and columns. n_quantity = =1 18.9 # YcoordinateNumber of cyclonequantities eyeprescribed (Spiderwebin centre) at current TIME pdropthe file quantity1 = 5300 x_wind # PressureName dropof atquantity1 cyclone eye (Spiderweb centre) at current TIME # Actual data field 1.388999(x_wind, y_wind, air_pressure, relative_humidity, air_temperature or cloudiness) unit1 1.388999 = m s-1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 1.388999 # Unit 1.388999of quantity1 (m s-1 155.0000 346.2500 357.5000 8.750000for velocities, Pa/ mbar for air_pressure, % for relative_humidity or cloudiness and Celcius for air_temperature) ### END OF HEADER TIME 20.00000 = 31.250000 hours since 2006-01-01 00:00:00 -06:00 42.50000 53.75000 # Fixed format: <time> <time 65.00000 76.25000unit> "since" <date> <time> <time zone> 101530.000 5300101300.000 5300101600.000 5300101550.000 5300101500.000 5300101300.000 53001013300.000 5300101400.000 5300 101430.000 5300101500.000 5300101130.000 TIME 101320.000 101260.000 = 1440 101620.000 1013400.000 101520.000 TIME = 1440 hours since 2006-01-01 00:00:00 -06:00 # Time where next dataset is# supplied x0Fixed format: <time> <time unit> "since" <date> <time> <time zone> 101298.544 = 114102108.4000102 101998.521 101928.544 101721.314 101811.152 1013410.400 # Xcoordinate of cyclone eye (Spiderweb centre) at current TIME y0101323.214 101430.000 101500.000 = 18.90000101130.000 101320.000 101260.000 101620.000 1013400.000 # Ycoordinate of cyclone eye (Spiderweb centre) at current TIME pdrop = 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.