Lagrangian Model Output at Empa







Lagranto (Wernli and Davies, QJRMS 1997) trajectories at Empa are based on 3D winds from ECMWF, usually at 1° x 1° resolution. Lagranto has been used extensively by Daniel Schaub in connection with satellite observations for studies of transboundary transport of air pollution.


Lagranto has been installed recently (Jan 07) on our Linux workstation (home/brd134/bin/lagranto). Scripts are available at ECMWF (ecgate) at /home/ms/ch/chb/mars (e.g. in subdirectory SCOUT) to retrieve meteorological input files from the MARS archive. ECMWF files are in GRIB format while Lagranto requires netCDF. For conversion of GRIB to netCDF the program /home/brd134/bin/fgrb2cdf is available.

Lagranto has been used to calculate 5-day backward trajectories for the following GAW stations:

  • Jungfraujoch (Jan 2000 - Jan 2006)
  • Mt. Kenya (July 2003 - Jan 2006)
  • Assekrem (July 2003 - Jan 2006)
  • Bukit Kototaban (July 2003 - Jan 2006)
  • Mt. Waliguan (July 2003 - Jan 2006)
  • Arembepe (July 2003 - Jan 2006)

It has also been used in the project TEMIS for back trajectory calculations started from GOME and SCIAMACHY pixels over Central Europe. Currently, trajectories are available for the years 1997 (GOME) and 2003-2004 (SCIAMACHY).

Global (1° x 1° x 60lev) 6-hourly GRIB files with parameters U,V,W,T are available completely for the period Aug 2003 - May 2006. For Europe, files at higher (0.5deg x 0.5deg) resolution are available for Jan 1997 - July 2004.

Analysis tools

  • Reading data: (part of HIPHOP distribution)
    Available at /home/brd134/IDL/hiphop on Linux or G:\134 Themen\Modellierung\brd\hiphop on Windows.
  • Plotting: HIPHOP visualization tool


  • Trajectories for GAW stations: /remote0/daily_trajek/ecmwf_traj/analysis@empa
  • Start position files for GAW stations: /local2/von_sun1a134_local/lagranto/tra/halclim
  • Trajectories for TEMIS: /remote3/poltrasat_temis
  • Start position files for TEMIS: /remote3/no2track_knmi_lagranto
  • ECMWF GRIB data: /remote1/ecmwf_data
  • Plots for TEMIS: /remote1/no2track_knmi_traj_plots
  • Plots for JFJ: /remote0/daily_trajek/ecmwf_traj/gifs (only for 2000 and 2001)