Backward trajectories starting point: height issue

Topics about the HYSPLIT trajectory model.
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coutre
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Joined: October 24th, 2016, 10:31 am
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Backward trajectories starting point: height issue

Post by coutre » October 25th, 2016, 9:18 am

Hello,

I am running backward trajectories on Hysplit with a high altitude starting point (Chacaltaya, Bolivian Andes; latitude 16° 20' 47'' S, longitude 68° 07' 44'' W, height according to Google Earth ~5350m). I plotted terrain height along trajectory with the vertical plot height units in Meters AGL, and surprisingly the resulting plot outputs a starting point at 3200m ASL. This questioned me: how does Hysplit determine the ground level on which are based the model's altitude outputs? I am hoping that could help me understand the ~2000 m altitude difference at the trajectory starting point.

Thank you for any answer!

ariel.stein
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Re: Backward trajectories starting point: height issue

Post by ariel.stein » October 25th, 2016, 10:01 pm

HYSPLIT can use heights above ground level (AGL) or above sea level (ASL). The default is AGL. When using ASL, HYSPLIT determines the terraing height from the input meteorological data.

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