HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Greetings!
So, I am running the online version of HYSPLIT, specifically the backwards trajectory, vertical velocity model.
The main issue I am encountering is that the algorithm tends to return data for ~800m below the requested altitude when in the "AMSL" altitude selection mode. I am presenting proof bellow:

Secondly, although I am entering altitude in AMSL (I am aware that the model converts them to AGL to run), the final trajectory plot has a title of "Meters AGL" despite displaying AMSL altitude values. Also, if I am not mistaken, there is no option of manually changing the title to AMSL.

Thank you for reading and evaluating my message,
I took care to not foolishly miss something obvious, apologies if I failed to do that,
Kind regards,
Andreas

There are two namelist parameters that control trajectory heights. They are KMSL and KAGL for specifying input height and output height, respectively. Description for them are found in https://www.ready.noaa.gov/hysplitusersguide/S410.htm and https://www.ready.noaa.gov/hysplitusersguide/S640.htm. Examine how these are set in your SETUP.CFG. If they do not appear in SETUP.CFG, their default values are used.