I have been quite successful running the trajectories off the website, but have not been able to get the downloaded software to work correctly. It seems to put out the default example graph every time, even after other meteorological data has been entered. Since I have been using Hysplit on the web, it doesn’t really matter. But I was wondering if the website accesses the hard drive, or if the software is actually not necessary and the website can be used instead? Are there things I can do using the software that are not available on the web? If so, what?

The Hysplit download software is completely independent of the web program. Using the PC version gives you some more flexibility in customizing the simulations and the graphics. The PC version is the only way you can run simulations using meteorological data no longer available on-line at our web site.

I’m not sure why you are having trouble with the PC version. I suggest that you go back and run the example case again and then make a slight change, perhaps another location and see if you get a different graphic. Examine the MESSAGE file in the \working directory. It may contain clues as to why the model is not working properly. If the model runs correctly you will have a new trajectory endpoint output file (default name = tdump). It is an ascii file you can view with Notepad. You can then run the trajectory plotting program from the command prompt: e.g ..\trajmdl\trajplot tdump. It then creates the graphic output file: trajplot.ps, which is also in ascii format and can be viewed with Notepad or printed directly on any Postscript printer.

Roland Draxler