...
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.
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.
...