1. Part 5: Advanced Trajectories
HANDS-ON EXERCISES
Part 5: Advanced Trajectories
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2. Example Simulations
Presented on the following slides are exercises for:
(1) running trajectories for one season,
(2) displaying them on a trajectory frequency plot, and
(3) displaying them by trajectory clusters.
The first slide of each example will present the problem to be answered, the next few slides will show the GUI inputs, and the last slide(s) will show the results.
It is recommended to click on the Reset button of the main HYSPLIT menu before proceeding in order to clear out any old cases in the working directory.
Also manually delete
all files in \hysplit4\cluster\working or move them to another directory
all ‘tdump’ files in \hysplit4\working.
Note: These runs were produced using HYSPLIT version 4.9 (released January 2010). Slight differences are possible with older/newer versions of the model.
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3. Exercise 1: Automated trajectory calculations
Assignment: Generate trajectories for one season
Source Location: 39.0N, 77.0W (near Washington, 500 meters AGL
Date/Time: December 2, 2008 through February 28, 2009,
once a 18 UTC (Hint: do one month at a time)
Duration: Backward, 24 hours
Meteorology: EDAS archive extract
(edas.dec extract, edas.dec extract, …)
Comment: The EDAS extract is an extract in the horizontal and vertical. The “Trajectory Setup” Top of the model should be set accordingly ( m) or there will be a NOTICE comment about extrapolation in the vertical in the MESSAGE file. If trajectories would go above the noted level, you would need the full dataset.
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4. Exercise 1: Inputs Run one trajectory
Set the start locations & meteorology:
Display the results:
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5. Exercise 1: Inputs Run one month of trajectories
Set the start/end date and time:
Notes:
Trajectory / Special Runs / Daily
Defaults to entire month (days 1-31), and 4 times a day (00, 06, 12, 18 UTC)
If year, month, day, of the previous step (one trajectory) were set to zeros, the trajectory would be fine, except the automated trajectories would not work. Year, month, day, MUST be non-zero.
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6. Exercise 1: Results One month of trajectories
There should be one trajectory file for each day (tdumpYYYYMMDD) in the directory specified in Trajectory Setup.
One way to view the trajectories is through the Trajectory Cluster Analysis section. We will come to this later.
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7. Exercise 1: Three-month set of trajectories
As was done for December, 2008, calculate trajectories for January (days 1-31) and February (1-28), Remember the meteorology from the last day of the previous month is needed to calculate a 24-h back trajectory from the 1st of the month.
Once the 3-month set of trajectories is complete, in /hysplit4/working, delete trajectory endpoints files with “tdump” in their name that are NOT part of the Dec-Jan-Feb exercise.
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8. Exercise 2: Trajectory frequency plot
Assignment: Create a trajectory frequency plot
Source Location: 39.0N, 77.0W (near Washington, 500 meters AGL
Date/Time: December 2, 2008 through February 28, 2009,
trajectories once a 18 UTC
Duration: Backward, 24 hours
Meteorology: EDAS archive extract
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9. Exercise 2: Inputs Trajectory frequency plot
Notes:
Trajectory / Display / Frequency
All trajectory endpoint files with “tdump” in their name in the /hysplit4/working directory are used.
First click Create file of trajectory filenames to make text file (INFILE) in the /hysplit4/working directory which lists the trajectory files to be used. Then click Execute Display.
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10. Exercise 2: Results Trajectory frequency plot
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11. Exercise 3: Trajectory cluster analysis
Assignment: Run a trajectory cluster analysis program to view the predominant flow regimes for winter View two different possible outcomes (i.e. final number of clusters).
Bonus: Display all the trajectories on one plot.
Source Location: 39.0N, 77.0W (near Washington, 500 meters AGL
Date/Time: December 2, 2008 through February 28, 2009,
trajectories once a 18 UTC
Duration: Backward, 24 hours
Meteorology: EDAS archive extract
Cluster Analysis Run_ID: Winter_
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12. Exercise 3: Inputs Trajectory cluster analysis
Step 1 inputs:
Notes:
Trajectory / Special Runs / Clustering / Standard
If any ‘blanks’ are in the Run_ID, the Run_ID will be the characters up to the first blank
Set endpoints folder accordingly, and delete unneeded ‘tdump’ files (above assumes you copied the files to /hysplit4/cluster/endpts)
use HELP button at bottom as needed
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13. Exercise 3: Inputs Trajectory cluster analysis
Cluster Step 2 …
click Make INFILE.
Verify filelist in the file INFILE in the cluster working folder specified in Step 1.
click Run cluster. This is the master computation step and can take a while with a large numbers of trajectories.
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14. Exercise 3: Inputs Trajectory cluster analysis
Cluster Step 2 (cont) …
click Display plot to produce the TSV plot
click Run. This makes a file CLUSEND.
Both indicate possible solutions of 3 and 8 clusters.
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15. Exercise 3: Inputs Trajectory cluster analysis
Cluster Step 3 …
Enter the final Number of Clusters (8)
Click Text. This makes a file CLUSLIST_N (N is the number of clusters), which is the text file that lists the trajectories that are in each cluster.
If you do not need the graphics, CLUSLIST_N is your result. The first column is the cluster number, the second column is the number of trajectories in each cluster.
If you want the graphics, see the next slides …
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16. Exercise 3: Inputs Trajectory cluster analysis
Cluster Step 3, Display Means
Notes:
Check “View” for the postscript window to automatically open
Select “None” for the Vertical Coordinate since it is not used
This example forces a fixed map domain by setting the centerpoint (“Center”) and zero “Rings” of given radius.
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17. Exercise 3: Inputs Trajectory cluster analysis
Cluster Step 3, Display Clusters
Notes:
Inputs are the same as for Display Means
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18. Exercise 3: Results 8-cluster solution
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19. Exercise 3: Results 3-cluster solution
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20. Exercise 3: Results Comparison*
Cluster 1 of 8
Cluster 4 of 8
Cluster 5 of 8
Cluster 1 of 3 + + =
Cluster 2 of 8
Cluster 7 of 8
Cluster 2 of 3 + =
Cluster 3 of 8
Cluster 6 of 8
Cluster 8 of 8
Cluster 3 of 3 + + =
*Determined from inspection of the plots, or files CLUSLIST_8 and CLUSLIST_3.
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21. Exercise 3: Bonus Trajectory cluster analysis
How do you display all the trajectories in one plot ?
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22. Exercise 3: Bonus Trajectory cluster analysis
How do you display all the trajectories in one plot ?
In Cluster Step 3
Set Number of Clusters to 1
Click Text
Run Display Clusters
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