Exercise #5




  • Problem #1 - The computational error tutorial (section 4.5) showed only minor differences when the initial trajectory height was 600 m compared to the calculation from 10 m, which showed a much larger difference. Repeat the calculation using an initial height of 10 m.

  • Hint - Edit and then run traj_error.bat or traj_error.sh.

  • Solution - Computational result. Can you explain how terrain might have caused the trajectory differences?

  • Problem #2 - See if you can figure out how to use the Run Daily menu to create a graphic with hourly mid-bounday layer trajectories for 24 h starting at 1700 UTC.

  • Hint - Retrieve traj_fwrd_control.txt and edit the trajectory setup menu to define a simple output file name with just one letter: T. Then open the Special Runs / Daily menu and set the start interval and duration to one followed by execute script to obtain 24 trajectories, one per output file.

  • Solution - Open the command line prompt and go to the HYSPLIT working directory and create a file of trajectory file names by entering the command dir /b T8309* >INFILE. Then open the trajectory plotting menu and enter +INFILE into the input endpoints field to obtain the multi-trajectory graphic.