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### How can I check if the top of the model domain?

Posted: **March 6th, 2019, 10:41 am**

by **szabob**

According to the HYSPLIT4 Users' Guide the default value of the top of the model is 10000, but it can set if the model domain exceed. How can I check if the default value is suitable and we can trust in the result?

Thank you for your response in advance!

### Re: How can I check if the top of the model domain?

Posted: **March 12th, 2019, 6:28 am**

by **szabob**

I tried to check the top of the domain with the following way:

1) run the profile.exe: cmd C:\hysplit4\exec>profile.exe –dc:\hysplit4\working\ -f20161025_gdas0p5 –y49 –x15 –t3

where the options:

-d is Input metdata directory name with ending \

-f the input metdata file name

-y the latitude (I used the starting location)

-x the longitude (I used the starting location)

-t the output time interval (hrs)

2) I received the profile.txt (attached)

3) calculation of the hyprid-sigma pressure levels to meter with hypsometric equation

h=RT/g ln(p0/p)

where

R is the gas constant of dry air: 287.04 J/kg/K

T the virtual temperature in K

p0 is the surface pressure (pressure of 2D field)

p the sigma-pressure levels (first colum in the 3D field)

I calculated the height based on the data 2016 10 25 00 and at 18:00 as well because it was the closest to the stating hour (17:00). I got result concerning the largest domain top: 26680 m.

Can someone inform me if this way is correct?

### Re: How can I check if the top of the model domain?

Posted: **March 18th, 2019, 8:35 am**

by **barbara.stunder**

Your calculation is correct. Check the MESSAGE file for a NOTICE about "extrapolation from level". Generally you don't want that.