HYSPLIT Forum: hysplitbbs.arl.noaa.gov

What is the relationship between the height of levels in the grid setup vs the top of model setting in the main Concentration setup menu please?
Say you set the height of levels to 5000 m AGL but the top of model is 10000 m AGL. Does this mean the plume is centred around 5000m but particles don't 'disappear' unless they go above 10,000 m?

The "top of model" in the CONTROL file is the vertical limit of the internal meteorological grid. It tells the model how much the calculation can go vertically. (https://www.ready.noaa.gov/hysplitusersguide/S262.htm)

The grid setup is for computing the concentration. If you set it to 5000 m, the model will calculate the concentration within the volume from the surface up to 5000 m. Particles above 5000 m will not be counted for the concentration, but still computed as long as they stay in the domain the met data are available.
https://www.ready.noaa.gov/hysplitusersguide/S313.htm