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Inconsistent altitude selection

Posted: November 4th, 2024, 5:01 am
by Weekday_Assassin
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

Re: Inconsistent altitude selection

Posted: November 18th, 2024, 7:47 am
by sonny.zinn
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.