Trajectory frequency and cluster analysis

Post any questions or comments regarding the Desktop PC version of HYSPLIT. This includes the model execution, GUIs, results, or graphics. Be sure to include the operating system you are using (Windows XP, Windows Vista, Windows 7, Windows 8, etc.
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Posts: 33
Joined: November 9th, 2012, 2:49 pm
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Trajectory frequency and cluster analysis

Post by arl.noaa »

I am running HYSPLIT on my PC using the GUI. I want to display trajectory frequencies. I have no problem creating the INFILE, but I'm not sure how to proceed. I've tried to define the grid resolution under concentration setup (concentration grid setup). Is this the correct place to define the grid? If so, how do I then run the trajectory frequency analysis? The help file says that the gridded binary output file is in the HYSPLIT concentration format, and that the trajectory frequency results can be plotted in the concentration routine. Can you provide more detailed directions as to how this can be done?

I'm also doing trajectory clusters, and I believe I need to have each trajectory as its own tdump file. I've tried using the trajectory run daily, and the directions listed on the questions page at, but neither of these are producing individual files per trajectory. Am I doing something wrong, or is there another way to calculate multiple trajectories with the output in individual files for each trajectory? I've been downloading the trajectories as individual files and can get the trajectory clusters to work, but it's slow.
Posts: 362
Joined: November 7th, 2012, 1:39 pm
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Re: Trajectory frequency and cluster analysis

Post by glenn.rolph »

You should just be able to click "Execute Display" and get the frequency plot. The grid is set in the "Create a Trajectory Frequency Plot" window where the grid options are 1, 2 or 4 degrees. Make sure "View" is checked so a window will automatically open and display the plot. Look at your file INFILE in c:\hysplit4\working. It should have this list of trajectory filenames.

Thank you for trying to follow Unfortunately, I realize we haven't kept the FAQ up to date. That was written before we had Run Daily, which is simpler to run. Basically, before running Run Daily, run a single regular trajectory. At Trajectory Setup, make sure you specify the trajectory starting year month date hour and, if you want to do trajectories for a whole month, specify all the archived files for the month and either the last file from the previous month or the 1st file from the next month. (Then with say a backward trajectory starting at 12z on the 1st of the month, it will continue to the last day of the previous month.) Display the trajectory to make sure it is OK. Then go to Run Daily and it will be automatically set for the month you have chosen, with that starting latitude, longitude, height. For a further description of this, see the training document at - automated trajectory calculation under Special Topics.
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