Inquiry About Adjusting Air Parcel Velocity in HYSPLIT
Posted: September 23rd, 2026, 10:42 am
I use HYSPLIT to estimate the potential source regions of migratory and vagrant birds, as well as to help determine suitable release locations when rescued birds are to be released back into the wild.
However, birds do not simply move at the speed of the wind.
They have their own airspeed relative to the surrounding air, and therefore may travel somewhat faster than the wind speed when flying with a tailwind.
For this reason, I would like to know whether HYSPLIT has an option that allows trajectories to be calculated using a velocity that is, for example, 1.2 or 2 times the actual wind speed.
If such an option is not currently available, would it be technically possible to develop or modify HYSPLIT to allow users to specify a multiplier for wind speed when calculating trajectories?
I would greatly appreciate any information or advice you could provide regarding this possibility.
Thank you very much for your time and consideration.
However, birds do not simply move at the speed of the wind.
They have their own airspeed relative to the surrounding air, and therefore may travel somewhat faster than the wind speed when flying with a tailwind.
For this reason, I would like to know whether HYSPLIT has an option that allows trajectories to be calculated using a velocity that is, for example, 1.2 or 2 times the actual wind speed.
If such an option is not currently available, would it be technically possible to develop or modify HYSPLIT to allow users to specify a multiplier for wind speed when calculating trajectories?
I would greatly appreciate any information or advice you could provide regarding this possibility.
Thank you very much for your time and consideration.