Workshop M&D / DKRZ 22.-24. 02. 2005 Jörg Wegner Dataformats, Postprocessing and Visualization Content: 1)Dataformats: Grib, NetCDF 2)Tools for Postprocessing:

Workshop M&D / DKRZ 22.-24. 02. 2005Jörg Wegner

Dataformats, Postprocessing and Visualization

Content:

1) Dataformats: Grib, NetCDF2) Tools for Postprocessing: cdo, cdat, (nco, PINGO)3) Examples for use of cdo4) Tools for Visualization: cdat, LE-Graphics, (GrADS)5) Examples for use of vcdat (GUI of cdat)6) Examples for use of LE-Graphics



GRIB NetCDF

Postprocessing:

Visualisation:

cdo, PINGOs cdo, cdat, nco

GrADS GrADS, cdat, vtkFerret, LE-Graphics



Why change from PINGO to cdo?-PINGO was designed for GRIB-files-NetCDF files have a different structure, that does not fit into the PINGO design.


Dataformats, Postprocessing and Visualizationnetcdf zzz {dimensions: lon = 192 ; lat = 96 ; lev = 1 ; time = UNLIMITED ; // (10 currently)variables: double lon(lon) ; lon:long_name = "longitude" ; lon:units = "degrees_east" ;double lat(lat) ; lat:long_name = "latitude" ; lat:units = "degrees_north" ;double lev(lev) ; lev:long_name = "pressure" ; lev:units = "Pa" ;double time(time) ; time:units = "day as %Y%m%d.%f" ;float q(time, lev, lat, lon) ; q:long_name = "specific humidity" ; q:units = "kg/kg" ; q:code = 133 ; q:table = 128 ; q:grid_type = "gaussian" ;// global attributes: :CDO = "Climate Data Operators version 0.9.5 " ; :source = "ECHAM5.2" ; :institution = "Max-Planck-Institute for Meteorology" ;}

NetCDF file information



ds8 55%grib -ginfo zzz.grb Rec : Position Size : V PDS GDS BMS BDS : Code Level : LType GType 1 : 0 36948 : 1 28 32 0 36876 : 133 20000 : 100 4 2 : 36948 36948 : 1 28 32 0 36876 : 133 20000 : 100 4 3 : 73896 36948 : 1 28 32 0 36876 : 133 20000 : 100 4 4 : 110844 36948 : 1 28 32 0 36876 : 133 20000 : 100 4 5 : 147792 36948 : 1 28 32 0 36876 : 133 20000 : 100 4ds8 56%grib -gdsinfo zzz.grb Rec : GDS NV PVPL Typ : xsize ysize Lat1 Lon1 Lat2 Lon2 dx dy 1 : 32 0 255 4 : 192 96 88572 0 -88572 358125 1875 48 2 : 32 0 255 4 : 192 96 88572 0 -88572 358125 1875 48 3 : 32 0 255 4 : 192 96 88572 0 -88572 358125 1875 48 4 : 32 0 255 4 : 192 96 88572 0 -88572 358125 1875 48 5 : 32 0 255 4 : 192 96 88572 0 -88572 358125 1875 48ds8 57%

Grib header information:



Climate Data Operators cdo:

- by Uwe Schulzweida (MPIM)- will replace the PINGO package- significant faster than the PINGO tools- written in ansi c , runs on LINUX, UNIX, Mac OS X- reads and writes NetCDF and GRIB files -- (and EXTRA, SERVICE)- Informations and Downloads viahttp://www.mpimet.mpg.de/~cdo/



Documentation• User's Guide (pdf 400KB)• Reference Card (pdf 100KB)• Introduction (pdf 100KB)• Online help with 'cdo -h operator‘

Release The current CDO version is 0.9.4, updated 3 January 2005.• Download source code (600KB)

cdo:







Examples for use of cdo:Grib to netCDF

cdo -f nc [-t table] copy zzz.grb zzz.nc

Table (containing Code name longname units):1 sftlf land_fraction [%]2 tos sea_surface_temperature [K]4 pr precipitation_flux [kg m-2 s-1]5 so sea_water_salinity [PSU]84 zobt sea_floor_depth [m]167 tas air_temperature [K]



Examples for use of cdo:GrADS description file

cdo gradsdes file.grb

file.ctl ---the GrADS description filefile.gmp ---the INDEX file

creates



Examples for use of cdo:Piping, missing, etc

cdo -f ext daymean MSLP.grb A1_psl cdo -f ext daymin T2MIN.grb A1_tasmin cdo -f ext daymax T2MAX.grb A1_tasmax cdo -f ext add -daymean APRL.grb -daymean APRC.grb A1_pr cdo -f ext sub -daymean TRADS.grb -daymean TRADSU.grb A1_rlds cdo -f ext sub -daymean SRADS.grb -daymean SRADSU.grb zwisch1_rsds cdo gtc,0.0 zwisch1_rsds zwisch2_rsds cdo setmisstoc,0.0 -ifthen zwisch2_rsds zwisch1_rsds A1_rsds cdo -f ext mulc,-1. -daymean AHFL.grb A1_hfls



cdat:

- graphic (cdat) and postprocessing (cdms modules) package for climate data- uses Python as scripting language- available GUI vcdat- support and download viahttp://www-pcmdi.llnl.gov/software/support.php







LE-Graphics:

- by Karin Meier-Fleischer (M&D) for PRISM- easy-to-use interface for simple 2d-graphics based on cdat/ cdms - stand-alone package for building plots with one command line- can be used with SRE for monitoring the model run



USAGE: LE-parameter.py -i <datafile> -var <variable> [-p <projection>][-lat <lat0:lat1>] [-lon <lon0:lon1>][-bounds <lat:lon>][-gxo <graphicsmethod>][-gol <overlay>][-gov <var_over>][-m][-mask <mask file>][-mvar <mask variable>][-gridfile <file>][-nc <value>][-dint <value>][-or <type>] [-pr <type>][-colors <coltab>][-user <uid>][-t <time>][-tser][-l <level>][-bg <value>][-u <units>][-yrev][-notext][-h]

LE-Graphics:

The easiest command:

LE_parameter.py -i "$DATA/clt_A1.nc" -var "clt"



Example 1: surface pressure with contour intervall 2500 PaLE_parameter.py -i "ps_A1.nc" -var "ps" -dint 2500 -colors "BlauGelbRot32" -pr "GIF" -o „ps_A1_dint2500.gif"



Example 2: 2m temperature in Mollweide projection withcontour intervall 2.5 K

LE_parameter.py -i "BOT_197801.nc" -var "temp2" -dint "2.5" -p "mollweide“-colors "BlauGelbRot32" -pr "GIF" -o "temp2_mollweide.gif"



Example 3: 2m temp with wind-vector overlay:LE_parameter.py -i "BOT_197801.nc" -var "temp2" -dint "2.5" -p "linear" -gol "vector" -gov "u10:v10" -colors "Rainbow32"



Example 4: Sea surface Temperature on curve linear grid

LE_parameter.py -i "SSTOCEAN.nc“ -var "SSTOCEAN" -p "linear" -m -colors "BlueToRed16"



Thank You!

Documents

Workshop M&D / DKRZ 22.-24. 02. 2005 Jörg Wegner Dataformats, Postprocessing and Visualization Content: 1)Dataformats: Grib, NetCDF 2)Tools for Postprocessing: