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Bandung, Indonesia 2012
Cosmin BARBU
Overview:
� Basics of GrADS
� Creating plots of COSMO model run
� Meteograms
�Sample of operative procedure using GrADS
Useful links for GrADS
Name Link
GrADS Home Page grads.iges.org/grads/gadoc
GrADS User's Guide grads.iges.org/grads/gadoc/users.html
GrADS Documentation Index grads.iges.org/grads/gadoc/gaddocindex.html
GrADS Script Library grads.iges.org/grads/gadoc/library.html
GrADS Tutorial grads.iges.org/grads/gadoc/tutorial.html
OpenGrADS opengrads.org/index.php
Graphics based on GrADS
grads Start GrADS session
open xxx.ctl Open ctl-file which describes the GRIB data tobe plotted.
d expression display expression, e.g. T, or 0.01*pmsl, U;V, T-273.15
draw title Some Description Write title over plot
printim file.png create png-file
c clear screen
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Important commands
set lon West [East] sets longitudes [deg E], e.g. "set lon 17 23.5"
set lat South [North] sets latitudes [deg N], e.g. "set lat -10 15"
set lev p1 [p2] sets level [hPa], e.g. "set lev 500"
set time time [time2] sets time in format hhZddmmmyyyy, hh=hour, dd=day, mmm=month, yyyy=year, e.g. "set time 15Z19jul2011"
q XX query , i.e. get information XX
q file description of the file
q dims information about set dimensions
q time information about time settings
q ctlinfo show content of control-file
set gxout XX Choose display style, e.g. contour, shaded, grfill, barb
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Graphic types: set gxout
shaded contour grfill6
More commands
set display color white white background of map
set mpdset hires use high-resolution coastlines/maps
draw string Hello 2.5 1.2 write string Hello at position 2.5 inches, 1.2 inches
cbar draw the colour bar (Standard script cbar.gs)
set clevs 0.1 0.5 1 5 10 25 50 75 100 set contour levels
set cmin 25 show only values above 25
set ccolor 2 set contour color
Basic commands are:
set
d (or display) draw
query
close open c (or clear)
See grads.iges.org/grads/gadoc/gaddocindex.html, especially for set
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Examples:
set gxout barb draw WMO wind barbsd skip(u_10m*2,4);v_10m*2 draw every 4th wind grid point as barb
(in knots)set gxout stream draw streamlinesd u_10m;v_10m draw wind at 10m as streamlinesd mag(u_10m,v_10m) draw wind speed (in m/s)d hdivg(u_10m,v_10m)*1.e4 draw divergence (10-4 s-1)d hcurl (u_10m,v_10m)*1.e4 draw vorticity (10-4 s-1)
set clevs 0.1 0.5 1 5 10 25 50 75 100 set contour levelsd tot_prec draw precipitation
condepth=(htop_con-hbas_con)/1000 compute convective cloud depth (in km)
d maskout(condepth, condepth-0.5 ) draw condepth >= 0.5 km; alternative:set cmin 0.5d condepth
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Graphics types: set gxout
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Let's play:
Try some commands with your own data.
Make a ctl-file with
gme2ctl.pl <GRIB-file>
For more information about gme2ctl usage type: gme2ctl.pl -h
Debug information with option -D (repeat -D for more debug information)
gme2ctl.pl -D
Exercise: try to reproduce the images from the previous slide.
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Let's play:
How to produce a ctl-file for grib files??
gme2ctl.pl -n c10 lfff0*0
Example 1:
set display color whitecopen c10.ctlq fileset t 1 78set lat -7set lon 108d t_2m-273.15draw title title T_2m evolution in (7S,108E)printim T_2m-evolution.png
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Let's play:
Example 2: Don't forget to open your ctl file!!!
run map_ncl.gsc
set gxout shadedset clab forcedd pmsl/100set gxout contourd pmsl/100run cbarn.gsdraw title pressure reduced to MSL [hPa]set strsiz 0.14draw string 1.4 8.3 COSMO-10kmprintim pmsl.png png x1024 y768quit
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Let's play:
Example 3: Cross section
run define_colors.gsrun map_ncl.gscopen lfff00150000p.ctlset gxout contourset lat -7set lon 105 116set lev 1000 450d t-273.15d u;v;mag(u,v)draw title Cross section on latitudineprintim lat.png png x1024 y768
cset lon 108set lat -10 -3set lev 1000 450d t-273.15draw title Cross section on longitudeprintim lon.png png x1024 y768
quit
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Let's play:
Example 4: Specific humidity
run define_colors.gsrun map_ncl.gscopen lfff00150000.ctlset gxout shadedset rbcols 0 41 42 43 44 45 46 47 48 49set csmooth onset cmin 0set cint 0.001d qv_sdraw title Specific humidity at the surfaceprintim qv_s.png
quit
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Let's play:
Example 5: Total precipitation
run define_colors.gsrun map_ncl.gscopen lfff00150000.ctlset gxout shadedset cmin 0.1set clevs 0.1 1 2 5 10 20 40 80 120 160 200set ccols 0 85 86 84 83 82 87 88 89 90 91 92d tot_preccbarn.gsdraw title Total accumulated precipitationprintim acc_prec.png
quit
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Let's play:
Example 6: 10m wind
run define_colors.gsrun map_ncl.gscopen lfff00150000.ctlset gxout shadedset rbcols 31 33 35 43 46 48 26 28 93d skip(u_10m,2,2);v_10m;mag(u_10m,v_10m)draw mapcbarn.gsdraw title Wind 10mprintim w_10m.png x1024 y768
quit
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Meteographs with meteo_plot.pl
Requirements
ASCII output of COSMO perl typically in /usr/bin/perl .gnuplot http://gnuplot.sourforge.net
Explanation with option –h:meteo_plot.pl –h
Problems? Use option –D (repeat –D for more debug information)meteo_plot.pl –D …
Information on content of a meteograph file:meteo_plot.pl –i M_*
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Simple usage
meteo_plot.pl M_Bandung -e pmsl,ff10m,dd10m,t2m,td2m,clch,clcm,clcl,rain_con,precipmeteo_plot.pl M_Bandung -e pmsl,ff10m,dd10m,t2m,td2m,clch,clcm,clcl,rain_con,precip -o meteo_Bandung.png
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Simple usage
meteo_plot.pl M_Bandung -e pmsl,ff10m,dd10m,t2m,td2m,clch,clcm,clcl,rain_con,precip –o meteo_Bandung_1.png -time '*:+52'
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Simple usage
meteo_plot.pl M_Bandung -e pmsl,t2m,tmin2m,tmax2m,precip -o meteo_Bandung_2.png -time '2012101712 : 2012101906'
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Example of operative Grads procedure
cd ~/cosmo/grads/postproc
Please, remark the GrADS scripts for plotting:
� model output parameter: clct_baz.gs, prec_24h_baz.gs, temperatura_baz.gs …� setting colors: define_colors.gs, color.gs, culori_precip2.gs, …. � define map projection: map_ncl.gs� legend bars: cbarc.gs, xcbar.gs, …� displaying orography domain: topo.gs
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Now, run ./make_photos.sh
After finishing take a look in ~/cosmo/grads/postproc/photos
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Thank you for your attention!