Extract GDAS 1° data

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aletadini
Posts: 2
Joined: September 26th, 2018, 9:26 am
Registered HYSPLIT User: No

Extract GDAS 1° data

Post by aletadini » September 26th, 2018, 10:08 am

Good morning,

my name is Alessandro and I'm working on a project about volcanic fallout hazard assessment in Ecuador, where I'm using HYSPLIT to model volcanic ash dispersal and deposition. In order to produce probabilistic hazard maps, I would need to run several simulations using a statistically meaningful metereological dataset: to this purpose I have used so far meteo data from the GDAS 1°archived data (https://ready.arl.noaa.gov/ready2-bin/e ... xtracta.pl) to simulate single eruptions.
Now I would like to use the whole dataset (Dec 2004-present) to run many simulations at different times.

My question is: Is there a way to extract the whole dataset but only for a specific area?
From the above-mentioned link I know that you can do that but only week per week, while on the FTP server you can download data in a faster way but for the whole world (and it would be too big the final file).

Sorry if this is off-topic or if it has been answered elsewhere
Thanks a lot
Best Regards

Alessandro

Fantine
Posts: 76
Joined: November 8th, 2012, 3:41 pm

Re: Extract GDAS 1° data

Post by Fantine » September 27th, 2018, 9:36 am

You may consider making a script to download the gdas1 data through the ftp://arlftp.arlhq.noaa.gov/pub/archives/gdas1/ and use a program "xtrct_grid" (in exec directory) to subset the original file (global) to your region of interest. This will reduce the file size.
In the script for running "xtrct_grid", you will need to provide met file directory, met filename, lat/long of the lower left corner of your subset domain, lat/long of the upper right corner, and the number of data levels you want to keep.

aletadini
Posts: 2
Joined: September 26th, 2018, 9:26 am
Registered HYSPLIT User: No

Re: Extract GDAS 1° data

Post by aletadini » September 28th, 2018, 9:38 am

Dear Fantine,

thanks a lot for your advice, I've just written the script and used xtrct_grid as you suggested and it worked fine
Thanks a lot!

Alessandro

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