3 years daily frequency backward trajectories

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blakeadam
Posts: 1
Joined: November 29th, 2021, 10:23 am
Registered HYSPLIT User: No

3 years daily frequency backward trajectories

Post by blakeadam »

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.
alicec
Posts: 411
Joined: February 8th, 2016, 12:56 pm
Registered HYSPLIT User: Yes

Re: 3 years daily frequency backward trajectories

Post by alicec »

Usually it is more efficient to split this type of task up into multiple HYSPLIT runs and this is what
I would recommend you do. How you split them up depends on the length of time your trajectories are running for,
how frequently you are starting new trajectories, number of starting locations and so forth. Generally this requires some
script writing for both running HYSPLIT and reading the output files.
You can find example scripts for running multiple HYSPLIT runs in the tutorial.
https://www.ready.noaa.gov/documents/Tu ... index.html
There are also some python and R packages that can help with running multiple HYSPLIT runs and reading the outputs.

To answer your other questions

- you can concatenate meteorological files simply using cat
viewtopic.php?t=899

- There is a trick for getting HYSPLIT to accept more than 12 meteorological files.
https://www.ready.noaa.gov/hysplitusersguide/S310.htm (see bullet 7)
while not available in the GUI, if the user is creating the CONTROL file themselves, two numbers can be specified here: the first being the number of unique grids and the second being the number of files in each grid. For example, an entry of 2 12 would mean that there are met files for 2 different grids (e.g., a regional and a global grid), and that there are 12 files being specified for each grid. The grids should be specified in order of resolution, with the highest resolution grids (i.e, the smallest horizontal spacing between grid points) being specified before lower resolution grids. The two entries for each file (directory and filename) are repeated for each file in the first grid, and then for each file in the second grid, and so on, for any subsequent grids. Note that the same number of files are required for each grid in this approach. Without the use of this approach (i.e., when only one number is specified) the maximum number of files that can be used in the simulation is relatively small, but with this second approach, a much larger number of files can be used in the simulation.
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