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Table Visualiser Editor
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Specifies the data (GRIB icon) from which to derive the cross-section profile. The input GRIB icon must specify a multi-level (pressure or model levels) upper air meteorological variable, in a latitude-longitude or Gaussian grid.
If the input data is specified in model levels, you must include the parameter LNSP should you want the orography and the vertical axis of the plot in pressure levels rather than model levels when visualising the output.
This application also supports GRIB data with general height-based coordinates.
If wind arrows are to be plotted, then the input data should include three-dimensional wind data, i.e. the u/v/w wind components should all be present.
If more than one time and/or forecast step is contained in the GRIB icon, it returns a set of cross sections.
Line
Specifies the coordinates of a transect line along which the cross-section is calculated. Enter coordinates (lat/long) of a line separated by a "/" (easternmost lat and long, westernmost lat and long). Alternatively, use the coordinate assist button.
The cross section is calculated from a set of geographical points taken along the input transect line. The point selection takes into consideration the resolution of the data and assures that a minimum of 64 points will be generated. Parameter Horizontal Point Mode selects the algorithm used to compute these points.
Note that it is possible to define a line through either pole by describing the line’s coordinates as follows. First, when specifying the latitudes of the two points, imagine that the latitude values go above 90 when you cross the North Pole and below -90 when you cross the South Pole. Next, if you wish a straight line, ensure that the two longitude values are the same as each other. An example demonstrates this. Say you wanted to defined a straight-line cross-section from 60S/25E to 60S/155W. This would be specified as -60/25/-120/25. The fact that one of the latitude values is below -90 indicates to Metview that a cross-section going through the South Pole is desired. Once this has been established, the fact that the two longitude values are identical tells Metview to use a straight line through the pole. If this is the intent, then only one unique longitude value is required, as the other one can be deduced. Giving Metview two different longitude values will cause a cross-section consisting of two curves to be produced.
Wind Parallel
Setting this option to On will produce a cross section plot of the projection of the wind onto the cross section plane (going from a 3D wind field to a 2D wind field projection). This is plotted using wind arrows. Valid values are On/Off.
Wind Perpendicular
Setting this option to On will produce a cross section plot showing the projection of the horizontal wind components onto the direction perpendicular to the cross section plane. The result is a one-dimensional quantity and is plotted with contour lines. Also produced is another cross section plot of the W component of the wind. Valid values are On/Off.
Wind Intensity
Setting this option to On will produce a cross section plot of the scalar wind intensity, plotted with contour lines. If one of the previous two parameters is On, then the intensity is that of the specified projection. Also produced is another cross section plot of the W component of the wind. Valid values are On/Off.
Lnsp Param
Specifies the parameter number of the Lnsp data, if you are using non-ECMWF data - ECMWF uses specific parameter numbers different from the WMO ones. Enter whichever parameter number is appropriate for your data.
U Wind Param
Specifies the parameter number of the U wind component data, if you are using non-ECMWF data - ECMWF uses specific parameter numbers different from the WMO ones. Enter whichever parameter number is appropriate for your data.
V Wind Param
Specifies the parameter number of the V wind component data, if you are using non-ECMWF data - ECMWF uses specific parameter numbers different from the WMO ones. Enter whichever parameter number is appropriate for your data.
W Wind Param
Specifies the parameter number of the W wind component data, if you are using non-ECMWF data - ECMWF uses specific parameter numbers different from the WMO ones. Enter whichever parameter number is appropriate for your data.
Horizontal Point Mode
Specifies how the geographical points along the input transect line will be computed. Valid values are Interpolate and Nearest Gridpoint. Setting this option to Interpolate will create a regular set of interpolated geographical points along the transect line. Setting this option to Nearest Gridpoint will instead select the nearest points from the data.
Vertical Coordinates
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Vertical Coordinate Param
Specifies the parameter number of the general height-based coordinates if Vertical Coordinates is set to User.
W Wind Scaling Factor Mode
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Specifies the type of plot to be generated. This also implicitly specifies the type of data which will be entered. The available modes follow a set format: the first part is either 'Geo' (geographical coordinates) or 'Xy' (more generic coordinates); the second part is 'Points' (individual points), 'Vectors' (individual points with vector information) or 'Binning' (the points will be gridded – see Binning).
Table Filename
Specifies the path to the ASCII table file to be used. Alternatively, drop an icon into the Table Data field, which overrides Table Filename.
Table Data
Drop an ASCII Table icon into this field to specify the data to be used. A Notes icon will also be accepted, since Metview cannot be expected to automatically discriminate any but the most common types of ASCII table data from other ASCII files. Note that Table Filename is an alternative way of specifying the file.
Table X Type
Specifies how the X values should be interpreted, as numbers or as dates. Only available for 'Xy' type plots.
Table Y Type
Specifies how the Y values should be interpreted, as numbers or as dates. Only available for 'Xy' type plots.
Table Variable Identifier Type
Specifies how to identify the columns to use: by Name or by Index (starting at 1).
Table X Variable
Specifies which variable/column to use for the x co-ordinates of the points. Can be a name or an index - see Table Variable Identifier Type. Only available for 'Xy' type plots when Table X Type is Number.
Table Y Variable
Specifies which variable/column to use for the x co-ordinates of the points. Can be a name or an index - see Table Variable Identifier Type. Only available for 'Xy' type plots when Table Y Type is Number.
Table X Missing Value
Points with this value in their x co-ordinate will not be plotted.
Table Y Missing Value
Points with this value in their y co-ordinate will not be plotted.
Table Longitude Variable
Specifies which variable/column to use for the longitude co-ordinates of the points. Can be a name or an index - see Table Variable Identifier Type. Only available for 'Geo' type plots .
Table Latitude Variable
Specifies which variable/column to use for the latitude co-ordinates of the points. Can be a name or an index - see Table Variable Identifier Type. Only available for 'Geo' type plots .
Table X Component Variable
When set to a 'Vectors' type plot, this parameter specifies which variable/column gives the magnitudes of the vectors in the X or longitude direction (e.g. U-component of wind). Can be a name or an index - see Table Variable Identifier Type.
Table Y Component Variable
When set to a 'Vectors' type plot, this parameter specifies which variable/column gives the magnitudes of the vectors in the Y or latitude direction (e.g. V-component of wind). Can be a name or an index - see Table Variable Identifier Type.
Table Value Variable
Specifies which variable/column supplies the values for the points. Can be a name or an index - see Table Variable Identifier Type.
Table Binning
Drop a Binning icon here. Only available for 'Binning' type plots.
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W Wind Scaling Factor
Specifies the vertical wind scaling factor if W Wind Scaling Factor Mode is set to User.
Level Selection Type
Specifies the method to define the output pressure levels when converting model level data to pressure levels. Options are:
- From Data (default)
- compute the absolute bottom pressure level from the data
- for each model level, compute the average pressure along the cross section line and then use this mean pressure as the vertical pressure co-ordinate for that level
- compute extra levels at the bottom by adding an offset (10 hPa) until it reaches the bottom pressure level, computed previously. This will avoid blank areas in the plot near the orography line.
- Count
- calculate the output pressure levels by taking into account the bottom and top pressure levels (Bottom Level and Top Level) and the given number of levels (Level Count). The computed levels will be evenly spaced on either a linear or a logarithmic scale depending on the value of Vertical Scaling.
- Level List
- use the given list of pressure levels (Level List)
Level List
Specifies a list of output pressure levels separated by a “/”. Only available if Level Selection Type is set to Level List.
Level Count
Specifies the number of output pressure levels if Level Selection Type is set to Count.
Vertical Scaling
Specifies the type of vertical axis - Linear or Log. Only available if Level Selection Type is set to Count.
Bottom Level
Specifies the lower limit of the cross section, i.e. the bottom pressure level (hPa). Only available if Level Selection Type is set to Count.
Top Level
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