Stratosphere-Troposphere Exchange Forecast

4-days trajectories are daily calculated at ETHZ using forecast data from the ECMWF. Air masses initially residing in the Atlantic/European stratosphere (Potential Vorticity larger than 2 pvu) and descending during the following four days by more than 300 hPa into the troposphere are shown.


  • Starting date of trajectories are reported on the top of each pictures
  • Dark blue, light blue, black dots give the trajectory position at times 0 h, 48 h and 96 h from the run start, respectively
  • Pressure levels (min, mean and max) of trajectories are written in the upper-right corner for times 0h, 48 h and 96h from the run start, respectively
  • Actual trajectory pressure levels (expressed as hPa) are reported by the colored scale

  • Calculated by M. Sprenger, Swiss Federal Institute of Technology Zurich - ETHZ

    Link to STE forecast data-base: