FLEXPART - Plotting total column mass

For preparations and running the simulation needed for this tutorial click here ...

The total column integrated mas is not an output of FLEXPART so we need to compute it. The macro to do the computation and plot the resulting fields is 'plot_total.mv'.

In the macro first we call mvl_flexpart_total_column() to compute the "tcmd" fields with units of "kg m**-2".

dIn="result_fwd/"
inFile=dIn  & "conc_s001.grib"

#Compute the total column integrated mass
g=mvl_flexpart_total_column(inFile,1)

Next, we define the contouring. The "tcmd" fields are automatically scaled into "ng m**-2" for contouring (see here for details)  but with the current value range it is better to use "g m**-2" units. To achieve it we simply multiply the "tcmd" fieldset with 1000:

g=g*1000

The contour definition itself goes like this:

cont_list=[0.00001,0.0001,0.0005,0.001,0.002,0.005,0.01,0.05]

#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",
    grib_scaling_of_derived_fields	: 	"off"
    )

Please note that by multiplying our fieldset by 1000 it became a derived fieldset. Since we do not want the automatic contour scaling to happen we need to set the contouring parameter grib_scaling_of_derived_fields to "off".

Next, we build the title with mvl_flexpart_title(). Please note that we need to explicitly specify the plotting units!

title=mvl_flexpart_title(g,0.3,"g m**-2")

Finally we define the mapview:

#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
	)

and generate the plot:

plot(view,g,conc_shade,title)

Having run the macro we will get a plot like this (after navigating to step 39h):