5-days trajectories of stratospheric air masses intruding into the troposphere by more than 300 hPa.
Starting date of trajectories are reported on the top of each pictures.
Dark blue, light blue, black and green dots give the trajectory position at times 0 h, 48 h, 96 h and 120 h, respectively.
The pressure (min, mean and max) of all trajectories is written in the lowest-right corner for times 0h, 48 h 96h and 120h.
Colours show the trajectory levels (expressed as potential vorticity).
Calculated by M. Sprenger (mailto: email@example.com) - Swiss Federal Institute of Technology Zurich - ETHZ