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[IDV #ABY-968018]: help with wrfout in IDV

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  • Subject: [IDV #ABY-968018]: help with wrfout in IDV
  • Date: Thu, 18 Feb 2010 06:36:41 -0700
Hi Robert-

> I'm pretty new to IDV and I'm trying to use it to view WRF
> data. It seems to be reading it pretty well but I'm having trouble with
> the relative humidity field. This trial and error method right now has
> me at an unfortunate crossroads. I was wondering if you could point me
> to someone that is familiar with reading wrfout files into IDV and to
> calculate different variables such as RH. I know I have to create
> formulas but I'm not having much luck in doing so, at least not for my
> current purposes.

Although the IDV can read in the raw WRF netCDF files and can do calculations, 
we recommend that users run one of the post-processing programs (WRFPost, 
ARWPost) on the file to destagger the grids and create the standard 
meteorological variables.   See the FAQ item on this at:

http://www.unidata.ucar.edu/software/IDV/docs/userguide/Faq.html#wrf

However, if you still want to try this with the raw data, you can use the 
Jython library.  There is a section in the IDV Workshop on using formulas:

http://www.unidata.ucar.edu/software/IDV/docs/workshop/formulas/index.html

In the latest nightly build, we just added a function to calculate RH from 
Temperature and Mixing Ratio.  So, you could create a forumula that calls
DerivedGridFactory.createRelativeHumidity(mixr,temp) and supply the appropriate 
fields from the grid.

However, the post processing software is much better and efficient at 
calculating these variables and I would strongly suggest you use one of those 
packages to precalculate the variables.  Most (if not all) other display 
packages require this as well.

Don Murray
> Hi, Tom.
> 
> I'm pretty new to IDV and I'm trying to use it to view WRF
> data. It seems to be reading it pretty well but I'm having trouble with
> the relative humidity field. This trial and error method right now has
> me at an unfortunate crossroads. I was wondering if you could point me
> to someone that is familiar with reading wrfout files into IDV and to
> calculate different variables such as RH. I know I have to create
> formulas but I'm not having much luck in doing so, at least not for my
> current purposes.
> 
> Thanks,
> 
> Robert
> 
> 


Ticket Details
===================
Ticket ID: ABY-968018
Department: Support IDV
Priority: Normal
Status: Open