3 years daily frequency backward trajectories

Topics about the HYSPLIT trajectory model.
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florin.unga
Posts: 5
Joined: February 3rd, 2015, 1:17 pm
Registered HYSPLIT User: Yes

3 years daily frequency backward trajectories

Post by florin.unga » December 3rd, 2015, 7:18 am

Hello, so I'm trying to do 3 years of daily frequency plot from 2012-2014. The problem is that in Hysplit I can use only 12 meteorological file. I downloaded for the moment only 2012 year, daily, gdas0p5, so I have 365 files. Is there a meteo file for the entire year? I think is larger than 130 GB.
1. The approach is to concatenate meteorological files? ( type file1 file 2 > out) ? or it's already exists a script to do this?
2. Let's say i resolve question 1, can I write all backtrajectories in 1 file? not one file per backtrajectories. or I need to create a script to read and write to another file the coordinates of backtrajectories.
3. It is normal for "display/trajectories/frequency to take more than half day to create the graph on an laptop I7 processor only for 3 days, 4 backtrajectories per day (0,6,12,18), or I'm doing something wrong...

Thanks

P.s.: I'm using windows.

barbara.stunder
Posts: 406
Joined: November 9th, 2012, 4:23 pm
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Re: 3 years daily frequency backward trajectories

Post by barbara.stunder » December 3rd, 2015, 9:01 am

First you need to create the trajectories, then you run the frequency program.

1. Yes, you can concatenate the HYSPLIT meteorology files. The PC GUI has Trajectory / Special Runs / Daily that can create trajectories for a month at a time, so it would make sense to concatenate such that there are <=12 files. Use one starting height. This gives you one file per trajectory.

2. The trajectory frequency program is designed for one trajectory per file.

3. That is longer than expected. Try the example in the HYSPLIT Tutorial at http://www.ready.noaa.gov/documents/Tut ... index.html, Section 5.1 Frequency Analysis.

florin.unga
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Joined: February 3rd, 2015, 1:17 pm
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Re: 3 years daily frequency backward trajectories

Post by florin.unga » December 4th, 2015, 10:11 am

Thank you a lot. It helped me.
Also, I used this tutorial: http://www.arl.noaa.gov/faq_hg10.php for merging trajectories

Max Simus
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Joined: June 8th, 2020, 7:41 pm
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Re: 3 years daily frequency backward trajectories

Post by Max Simus » June 17th, 2020, 10:38 am

Good afternoon,
First, I would like to thank you for your response. it is very helpful. However, I have a question regarding Trajectory / Special Runs / Daily. Is this a backward trajectory. because I am trying to do the same for 10 years on GUI and still wondering about creating trajectories. Thanks, Max
barbara.stunder wrote:
December 3rd, 2015, 9:01 am
First you need to create the trajectories, then you run the frequency program.

1. Yes, you can concatenate the HYSPLIT meteorology files. The PC GUI has Trajectory / Special Runs / Daily that can create trajectories for a month at a time, so it would make sense to concatenate such that there are <=12 files. Use one starting height. This gives you one file per trajectory.

2. The trajectory frequency program is designed for one trajectory per file.

3. That is longer than expected. Try the example in the HYSPLIT Tutorial at http://www.ready.noaa.gov/documents/Tut ... index.html, Section 5.1 Frequency Analysis.

aring
Posts: 29
Joined: June 12th, 2020, 7:04 am
Registered HYSPLIT User: Yes

Re: 3 years daily frequency backward trajectories

Post by aring » June 29th, 2020, 10:06 am

Hi Max,
You can run forward or back trajectories, which you designate in the Trajectory > Setup Run menu.
When doing Trajectory > Special Runs > Daily, this menu requires a day range that runs forward in time.
This means, your start date for the daily trajectories should be the furthest date in the past for which you would like to execute a trajectory.
For example:
Screen Shot 2020-06-29 at 9.56.10 AM.png
In this menu, you can select the direction for the trajectories. This then automatically changes the total run time to negative (if back trajectory) or positive if (forward trajectory). Notice the start date is January 01, 2010 at 00z, ten years ago. This is the furthest date in the past for which I want to start a back trajectory.
Be sure to save the trajectory setup menu.
Screen Shot 2020-06-29 at 10.00.54 AM.png
Now, once you get to the Trajectory > Special Runs > Daily menu, notice the start time is again January 01, 2010 at 00z, and I have selected trajectories to run every 24 hours for the next 500 days.
Based on this setup, daily back trajectories starting at 00z between January 01, 2010 and May 16, 2011 at 00z will be executed. This of course requires appropriate met files to be available for the full duration of your simulations.
Hopefully this makes sense.

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