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Table of Contents

Preparations

First start Metview; at ECMWF, the command to use is metview (see Metview at ECMWF for details of Metview versions). You should see the main Metview desktop popping up.

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If we run this macro (or alternatively right-click execute the FLEXPART Run icon) the results (after a minute or so) will be available in folder 'result_fw_conc' . The computations were actually taken place in a temporary folder then metview copied the results to the output folder. If we open this older we will see two files there:

• conc_s001.grib is GRIB file containing the gridded concentration fields
• tr_r1.csv is CSV file containing the plume trajectories

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Please note that these are not the original outputs form FLEXTRA but were converted to formats more suitable for use in Metview. For details about the FLEXPART outputs please click here.

Visualising gridded fields

To plot a particular parameter and level we need to filter the desired dataset from the resulting FLEXPART output file. Unfortunately, Metview's Grib Filter icon cannot handle these files (partly due to the local GRIB definition they use) so we need to use other means to cope with this task. For this reason and also to make FLEXPART output handling easier a set of Metview Macro Library Functions were developed. We will heavily use these functions in the examples below.

Inspecting the file

Before seeing the macro code to generate the plot First we inspect the 'conc_s001.grib' GRIB file containing the fields we want file itself we wanted to plot. Double-click on the 'conc_s001.grib'  GRIB icon' in folder 'result_fw_conc' to start up the Grib Examiner and . We can see that it this file only contains "mdc" (=Mass density concentration) fields. We can find out further details about this parameter by setting the Dump mode to Namespace and Namespace to Parameter:

Generate the plot

The macro to visualise the concentration fields on a given level is 'plot_level.mv'.

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Finally we define the view with the map:

#Define coastlines
coast_grey = mcoast(
	map_coastline_thickness	:	2,
	map_coastline_land_shade	:	"on",
	map_coastline_land_shade_colour	:	"grey",
	map_coastline_sea_shade	:	"on",
	map_coastline_sea_shade_colour	:	"RGB(0.89,0.89,0.89)",
	map_boundaries	:	"on",
	map_boundaries_colour	:	"black",
	map_grid_latitude_increment	:	5,
	map_grid_longitude_increment	:	5
	)

#Define geo view
view = geoview(
	map_area_definition	:	"corners",
	area	:	[40,-25,66,9],
	coastlines: coast_grey
	)

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