HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hey guys,

I'm just wondering is it possible to do both:
Multiple Trajectories in Space https://ready.arl.noaa.gov/documents/Tu ... ensem.html
and
Multiple Trajectories in Time

Unless I've misunderstood ensemble releases at different heights and not other locations and when I changed the starting locations in setup the output was the same



Aim is to have a 3 by 3 grid (at say 0.5 degrees apart) with each point releasing a trajectory every hour to build up a big picture of where the air has gone to. I've seen both done separately but not together. Thanks in advance for the help

The ensemble form of the model automatically starts multiple trajectories from the selected starting point. Each member of the trajectory ensemble is calculated by offsetting the meteorological data by a fixed grid factor as defined in the Advanced Trajectory Configuration tab. The default offset is one meteorological grid point in the horizontal and 0.01 sigma units in the vertical. This results in 27 members for all-possible offsets in X, Y, and Z. After the model calculation has completed, use the normal Trajectory Display tab to view the results. Because the offset is computed in both directions in the vertical from the starting location, a starting location at the ground would not provide an optimal configuration for this type of simulation. The default vertical offset is about 250 m. Therefore this should be the minimum starting height for ensemble trajectories, unless the default offset is changed in the namelist file.