input data for trajectory calculation

[sangan1161]

Hi,

I have mentioned this question elsewhere in the forum, but maybe it got lost because it was in the middle of some data conversion questions.
What kind of input data do I need to calculate trajectories? I have found different information on what is needed and what is optional and I'm still a bit puzzled about that, especially I'd like to know what is the influence of using or omitting the "optional" data. Does the model output is better? Does it avoid model crashes? Does it improve convergence?
I'm working now with some CSFR reanalysis data and some of the (probably?) optional data is not available. hysplit is still running and the results are close to what I get with the CSFR forecast data (which includes the optional data), and maybe the difference is only due to the difference between forecast and reanalysis. But I'd like to better understand what is the role/consequence of using different kind of input dataset.

From what I understood I need
-geopotential height
-temperature
-u velocity
-v velocity
-vertical velocity
but I'm not sure about the role/necessity of
-rel. humidity
-rel. humidity above ground
-temperature above ground
-u velocity above ground
-v velocity above ground
-pressure (or reduced pressure)


Thanks for sharing your experience about this or pointing me to some reference where this would be explained.

[ariel.stein]

To calculate a trajectory HYSPLIT needs the following surface variables: geopotential height (or surface pressure) , temp, u, and v and the following vertical fields u, v, w, temp and pressure. The model will crash if these variables are not present. Additional variables are used for the dispersion calculation.