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[IDV #TSU-257401]: Using Formulas

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [IDV #TSU-257401]: Using Formulas
  • Date: Fri, 10 Apr 2020 13:00:26 -0600
> > Full Name: Vanessa Vincente
> > Email Address: address@hidden
> > Organization: UCAR/The COMET Program
> > Package Version:
> > Operating System:
> > Hardware:
> > Description of problem: Hello IDV Support,
> >
> > In my Data Choosers, I have uploaded a .gem file (it is an archive file of 
> > NAM model forecasts). I would like to create a display of the 1000-500 mb 
> > Average Relative Humidity. This field is not available in the .gem file, so 
> > I am trying to create a formula to calculate the 1000-500 mb Average 
> > Relative Humidity.
> >
> > Can you please help me create a formula to calculate this?  I do have a 3D 
> > grid field in my .gem file that allows me to select Relative Humidity at a 
> > particular pressure level.
> >
> > Many thanks in advance for your help!
> > Vanessa
> >
> >
> 
> Hi Vanessa,
> 
> It is very easy to create a simple (a+b)/2 formula in the IDV:
> 
> 1) load the data
> 2) Formula > Grids > Define a grid diagnostic, and select a display type
> 3) you can enter (a + b )/2 or avg(a,b) in the popup window, click OK
> 4) In next popup window, select a and b to be RH at 500 and 1000 levels
> ....
> 
> Let me know if this doesn't help.
> 
> Yuan

If you need to do the vertical average from 1000 to 500, you can use the 
formula:

Formula > Grids > Averages > Vertical Average Weighed

and then select the RH, and subset the vertical levels from 1000 to 500.


Yuan

Ticket Details
===================
Ticket ID: TSU-257401
Department: Support IDV
Priority: Normal
Status: Open
===================
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