Preparing Initial and Boundary Data
Running INT2LM
Ulrich Schättler, Ulrich Blahak
Alexander Smalla
Deutscher Wetterdienst
Zentrum für GeoInformationswesen
BU Research and Development
der Bundeswehr
Department for Numerical Modelling
Gruppe Meteorologie beim DWD
Up to now
 Up to now you know how to modify the variables from the run-scripts and
start the job
 IN_DIR, INIDIR, BD_DIR, LM_DIR, OUTPUT, …
 mpirun / aprun <path of binary>
 But you had to run the simulation for the reference data set (2013051312)
and did not modify the Namelist Input.
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Coming up next
 Now you will try to modify the Namelist Input for INT2LM
 Chapter 2 of the Tutorial explains some of the most important Namelist
variables and gives some background
 LMGRID: The Model Domain
 GRID_IN: Coarse Grid Model Data
 DATA:
Specifying Data Characteristics
 CONTRL: Parameters to Control the INT2LM
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Possible Simulations
 For these exercises we provide an ICON data set and a GME data set:
 GME: For 29th of January 2015, up to 48 hours, 3 hourly increment
 ICON: For 4th of March, 2015, up to 78 hours, 3 hourly increment
 Both data sets are provided for 4 regions:
 Europe
 Africa
 Asia
 South America
 choose a date and a region, then select an
appropriate run-script.
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Which Run-Script to Use?
 In the int2lm_141125_2.01-directory there are different run-scripts
 runicon2eu: for ICON input data
 rungme2eu: for GME input data
 runeu2de: for COSMO_EU input data and 2.8 km resolution for the
(fine-grid) COSMO Model
 Check the number of processors, directory names and batch settings.
 NPX=4, NPY=5,
 LM_EXT, IN_EXT, IN_DIR, LM_DIR
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Choosing a domain
 The domain is specified in the Namelist group /LMGRID/
 You have to modify
 startlat_tot, startlon_tot:
coordinates of the lower left grid point in rotated (!) coordinates
 pollat, pollon:
geographical coordinates of the rotated North Pole
 dlon, dlat:
resolution (0.0625 ~ 7 km; 0.025 ~ 2.8 km)
 ie(lm)_tot, je(lm)_tot, ke(lm)_tot:
size of the model grid in grid points
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Domains on a Rotated Grid
Rotated grid on the sphere
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and a regional domain
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Choosing a domain
 You first need an external parameter data set for the region you have chosen.
See /e/uhome/fegast3/Training_2015/topo for such data sets.
 We provide 4 different external parameter data sets:
 all with 7 km resolution: dlon/dlat=0.0625
 see the pictures of the domains in the Tutorial, Appendix C-2.
 The rotation of the domain (pollon=…, pollat=…) is also given there
 The pictures contain latitudes and longitudes (in rotated coordinates, where
appropriate)
 The coordinates of the start point can be chosen from these pictures:
 startlat_tot = …,
startlon_tot = …
 Size of the domain: ielm_tot = …, jelm_tot = …, kelm_tot = 40,
 With a resolution of 0.0625 you need 16 grid points for 1 degree!
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Specifying the Input Data
 In the group /CONTRL/ you have to specify
 yinput_model = ′GME′ or
 yinput_model = ′ICON′
 Then you need to specify additional variables in /GRID_IN/:
 For GME: ni_gme = 384, i3e_gme = 60, ke_soil_in = 7,
 For ICON:
yicon_grid_cat =
′/e/uwork/fegast3/ICON_2015030400/<region>/′
yicon_grid_lfn
= ′icon_grid_<region>_R03B07.nc′
ke_in_tot = 90, ke_soil_in = 7,
nlevskip = 20,
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Specifying the Input Data (II)
 Then you need to specify additional variables in /GRID_IN/:
 For driving models with regular grids:
startlat_in_tot, startlon_in_tot,
dlon_in, dlat_in,
pollat_in, pollon_in,
ie_in_tot, je_in_tot, ke_in_tot,
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Specifying Data Characteristics: /DATA/
 External parameters for the COSMO domain:
 ie_ext = …, je_ext = …,
 ylmext_lfn = ′cosmo_<region>_0.0625_aaaxbbb.g1′
 ylmext_cat = ′/e/uhome/fegast3/TRAINING_2015/topo/′
 ylmext_form_read = ′grb1′
(or ′apix′)
 External parameters for the coarse grid input model:
 yinext_lfn=′invar.i384a′
(GME)
 yinext_lfn=′icon_extpar_<region>_R03B07_20141202.nc′
(ICON)
 yinext_cat=′/e/uwork/fegast3/ICON_2015030400/<region>/′
 yinext_form_read=′ncdf′
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Specifying Data Characteristics: /DATA/ (II)
 Coarse grid input data
 For ICON
yin_hhl=′icon_hhl_<region>_R03B07.nc′
 For GME
ybitmap_cat=′/e/uwork/fegast3/GME_2015012900/<region>/′
ybitmap_lfn=′bitmp40x/′,
 For all
yin_cat=′/where/data/is/located′
yin_form_read=′apix′
 COSMO grid output data
 ylm_cat=′/where/data/is/located′
 ylm_form_write=′grb1′
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Parameters to Control the INT2LM Run
 Forecast time, domain decomposition and driving model
 ydate_ini=′2015030400′
is set by script-variable DATE
 hstart=0.0, hstop=78.0, hincbound=3.0,
 linitial=.TRUE.,
 lboundaries=.TRUE.,
 yinput_model=′ICON′
 nprocx=4, nprocy=5,
is set by script-variables NPX, NPY
 Take a look to the Tutorial, Section 2.6 for further informations.
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Some Problems
 GME: missing Namelist variables ybitmap_lfn, ybitmap_cat, nbitmap
 ICON: reading data with grib_api: have to define environment variable
GRIB_DEFINITION_PATH: in the run-script before the aprun-command
 External Parameters for COSMO: Not all variables could be read or
interpolated:
 Set itype_albedo=1 (not 3)
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Now try to produce initial and
boundary data for a special
COSMO region
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Thank you
very much
for your
attention
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