HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hi, I am trying to correlate the outputs from web-based and desktop Hysplit using the same input parameters to double check the output data.
HOWEVER I can see from the Control files that the default parameters are set differently:
- Desktop has 1 source point height (1 ‘specie’). Web has 2 source points and creates a linear column of output between them– why does the web do this by default?
- Desktop default has 1 concentration grid. Web has 6 as default. What effect does this have on the calculations and output? How many should I use for a point source?

The web based HYSPLIT attempts to guess what will be good default parameters based on the release type you pick.
For a generic chemical release it uses a default of releasing the substance from 0 to 50 m. This is a good default to pick
if you don't have more specific information on the release.
You can change this and other defaults by choosing 'Advanced Options' on the web.

The concentration grid(s) defines the spatial and temporal resolution of the output concentration files as
well as the domain over which concentrations are calculated.
The following are a few reasons that multiple concentration grids can be helpful.

- you need a small area of high resolution around the source surrounded by a larger area of lower resolution
- you have several areas that you want concentration output at - e.g. measurements stations which are fairly far apart in
space and you just want the concentrations around the measurement stations.
https://www.ready.noaa.gov/hysplitusersguide/S313.htm