Trajectory ensemble mode at low altitude

[annahs]

Hi There,

I would like to run HYSPLIT in the trajectory ensemble mode, but my starting location is only at an elevation of 15m. Would there be an issue with running the ensemble and then ignoring the 9 trajectories calculated by displacing the meteorological grid upward (i.e ignore the trajectories calculated when running with meteorology from "below ground")?

Thanks!

[ariel.stein]

Yes, you can ignore the trajectories that start "below" the ground. However, your ensemble will only have 18 members instead of 27.

[annahs]

Great, thanks very much for your reply. For the remaining 18 trajectories, are there any issues with moving the meteorological grid around in such close proximity to the ground?

Thanks again!

[ariel.stein]

Yes, it might be an issue because the trajectories that are close to the ground might hit it and will not provide any further information regarding the transport. For a discussion about the issue of trajectories reaching the ground please check the following forum discussion.
viewtopic.php?f=27&t=295&p=2336&hilit=t ... ound#p2336