## Computed Vertical Wind Speed Values

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jcahill1124
Posts: 4
Joined: February 17th, 2021, 3:29 pm
Registered HYSPLIT User: Yes

### Computed Vertical Wind Speed Values

Hello.

When I looked in the 'Initial CONTROL File Section,' I found that if a given file does not have a vertical wind speed variable, the vertical motion will be computed from the horizontal velocity divergence. Is there any way to locate the values of the vertical motion/wind speed if given a certain region? I don't mind getting my hands dirty in the code to run an executable.

Thank you.
Fantine
Posts: 118
Joined: November 8th, 2012, 3:41 pm

### Re: Computed Vertical Wind Speed Values

You can use the "profile" program to extract the vertical wind (WWND) from the ARL formatted file for a location with given lat/long.
For running with command lines => [your HYSPLIT directory]/exec/profile.
For using GUI => https://www.ready.noaa.gov/hysplitusersguide/S132.htm
jcahill1124
Posts: 4
Joined: February 17th, 2021, 3:29 pm
Registered HYSPLIT User: Yes

### Re: Computed Vertical Wind Speed Values

Hi Fantine,

I've attempted this, but my file (GDAS 0.5) does not have WWND variable. Instead, HYSPLIT computes this from the horizontal velocity divergence. I was curious how I could find the values of this calculation.
Fantine
Posts: 118
Joined: November 8th, 2012, 3:41 pm

### Re: Computed Vertical Wind Speed Values

The subroutine for computing WWND from the divergence is [your HYSPLIT dir]/library/hysplit/metdiv.f.
You may consider using vmixing.f (which extract meteorological stability parameters) to add WWND in the extraction. It is [your HYSPLIT dir]/source/vmixing.f