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Content: Dataformats: Grib, NetCDF

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Presentation on theme: "Content: Dataformats: Grib, NetCDF"— Presentation transcript:

1 Content: Dataformats: Grib, NetCDF Tools for Postprocessing: cdo, cdat, (nco, PINGO) Examples for use of cdo Tools for Visualization: cdat, LE-Graphics, (GrADS) Examples for use of vcdat (GUI of cdat) Examples for use of LE-Graphics

2 GRIB NetCDF Postprocessing: cdo, PINGOs cdo, cdat, nco Visualisation: GrADS GrADS, cdat, vtk Ferret, LE-Graphics

3 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.

4 NetCDF file information
netcdf 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 " ; :source = "ECHAM5.2" ; :institution = "Max-Planck-Institute for Meteorology" ; } NetCDF file information

5 Grib header information:
ds8 55%grib -ginfo zzz.grb Rec : Position Size : V PDS GDS BMS BDS : Code Level : LType GType 1 : : : : 2 : : : : 3 : : : : 4 : : : : 5 : : : : ds8 56%grib -gdsinfo zzz.grb Rec : GDS NV PVPL Typ : xsize ysize Lat1 Lon1 Lat2 Lon2 dx dy 1 : : 2 : : 3 : : 4 : : 5 : : ds8 57%

6 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 via

7 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)



10 Examples for use of cdo: Grib to netCDF
cdo -f nc [-t table] copy zzz.grb 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]

11 Examples for use of cdo: GrADS description file
cdo gradsdes file.grb creates file.ctl the GrADS description file file.gmp the INDEX file

12 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

13 cdat: graphic (cdat) and postprocessing (cdms modules) package for climate data - uses Python as scripting language available GUI vcdat support and download via



16 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

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

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

19 Example 2: 2m temperature in Mollweide projection with
contour intervall 2.5 K -i "BOT_ nc" -var "temp2" -dint "2.5" -p "mollweide“ -colors "BlauGelbRot32" -pr "GIF" -o "temp2_mollweide.gif"

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

21 Example 4: Sea surface Temperature on curve linear grid -i "“  -var "SSTOCEAN" -p "linear" -m -colors "BlueToRed16" 

22 Thank You!

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