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[IDV #TJF-848962]: Help plotting 2 m winds

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  • Subject: [IDV #TJF-848962]: Help plotting 2 m winds
  • Date: Tue, 06 Apr 2010 08:33:26 -0600
Hi-

> I am having difficulty figuring out how to plot surface winds in IDV. I
> am using the grib output data from WRF EMS V3.1 and would like to use
> IDV to plot the winds at the surface of the model, or at 2m. I have tried
> plotting u,v wind @isobaric and @hybrid, but am not sure how to tell the
> corresponding heights of these.
> 
> How do you know what height corresponds to the number 1 hybrid level,
> for example?
> 
> Overall, I would like to plot the combined U and V winds as wind barbs,
> and overlap the wind barbs with the topography.
> 
> There is a WRF output variable called U WIND OF MDL SFCS and V WIND OF MDL

I'm not sure what these variables are, but I'm guessing that they are winds at 
the model surface (essentially the 2 meter winds).

Are these listed under the 2D grids?  If there is only one level, the IDV 
categorizes the data as 2D grids.  To plot these as barbs or vectors, you can 
use the Formulas Data Source and the Grids->Make flow vectors from grid 
relative u and v data formula.  Select the type of display you want and when 
prompted select the u and v components you want.

If you want to have this option presented automatically, add the variable names 
as parameter aliases.  When you have your data loaded in, right click on the U 
WIND OF MDL SFCS and it should pop up a menu of 'Add "XXXXX" as alias for; with 
sub menus labelled Canonical Name N.  Find the UREL and VREL items (the 
canonical names are alphabetical) and set the variables as aliases for the 
right canonical name respectively.

The next time you load in your data (or if you do a reload on that Data 
Source), you should see an Flow Vectors field under the 2D->Derived Field 
category.

Don Murray

> Thank you for your time and help.
> 
> Regards
> Danielle Groenen
> 
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Ticket Details
===================
Ticket ID: TJF-848962
Department: Support IDV
Priority: Normal
Status: Open