For preparations and running the simulation needed for this tutorial click here ...
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To start these tutorial please enter folder 'forward'. |
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To plot a particular parameter and level we need to filter the desired fields from the resulting FLEXPART output GRIB 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 use these functions in the example below. |
Inspecting the FLEXPART GRIB file
Before seeing the macro code to generate plot the plot data we inspect the file itself we wanted to plotwork with. Double-click on the 'conc_s001.grib' GRIB icon' in folder 'result_fwfwd' to start up the Grib Examiner. We can see that this our file contains the "mdc" (=Mass density concentration) fields we want to visualise. We can find out further details about this parameter by setting the Dump mode to Namespace and Namespace to Parameter in the examiner:
Generating the plot
The macro to visualise the concentration fields on a given level is 'plot_conc.mv'.
In the macro first we define the level (8000 m) and the parameter ("mdc") we want to plot. Then we call the Macro Library Function flexpart_filter() to extract the data.
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dIn="result_fwd/"
inFile=dIn & "conc_s001.grib"
lev=8000
par="mdc"
#Read fields on the given height level
g=flexpart_filter(source: inFile,
param: par,
levType: "hl",
level: lev) |
Next, we define the contouring
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. The
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"mdc" fields have the units of "kg m**-3
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" but with the current value range "ng m**-3
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" units would better fit for contouring. To achieve this we simply multiply the "mdc" fieldset with 1012:
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g=g*1E12 |
The contour definition itself goes like this:
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#The contour levels
cont_list=[1,10,50,100,150,200,250,500,750,1000,2000,6000]
#Define contour shading
conc_shade = mcont(
legend : "on",
contour : "off",
contour_level_selection_type : "level_list",
contour_level_list : cont_list,
contour_label : "off",
contour_shade : "on",
contour_shade_method : "area_fill",
contour_shade_max_level_colour : "red",
contour_shade_min_level_colour : "RGB(0.14,0.37,0.86)",
contour_shade_colour_direction : "clockwise",
contour_method : "linear"
) |
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Finally we define the map view with the map:
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#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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