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[IDV #WYC-198714]: IDV 4.1u1: Vertical cross section plots conforming to variable surface elevation

> IDV support,
> 
> I’m using IDV v4.1u1 (latest nightly build) to plot vertical cross sections 
> of WRF-ARW model output. This output is on sigma coordinate surface (and 
> hence terrain following at the surface), but when I plot data (such as 
> vertical velocity, which is defined on grid surfaces that include the terrain 
> surface itself), the bottom edge of the plot does not conform to the 
> superimposed terrain elevation plot—rather, it seems to cut off at a fixed 
> elevation, around 190 meters (which intersects the terrain profile).

Dave,
    I discussed your model result with one WRF support people at MMM, she said 
the gap between data and the terrain is normal. If you want to make the gap 
smaller, you can change the sigma level to 1, 0.997, .... instead of 1, 
0.993..., some software does interpolate the data to make it looks better. I am 
not sure if this is the case for the ncl.


Yuan
> 
> Is there a way to get the bottom of the plot to conform to the underlying 
> terrain? (I know this is possible using NCAR graphics, for example). And what 
> determines the apparent elevation of the bottom of the plot?
> 
> I’ve included an IDV bundle to illustrate the point. It shows (among other 
> things) a vertical cross section plot of vertical velocity with horizontal 
> wind speed contours superimposed, along with a terrain profile. The data come 
> from a NetCDF file located at 
> http:://virga.sfsu.edu/data/wrf/<http://virga.sfsu.edu/data/wrf/>wrfout_2013-11-21_12_GFS_CenCal_BayArea_EastBay.1.nc
> 
> — Dave
> 
> 
> ****************************************************************
> *                                      |         __ __    \|/  *
> *   Dr. Dave Dempsey                   | )   ^  /|| ||\  --0-- *
> *   Dept. of Earth & Climate Sciences  |) ) ^  / ||_|| \  /|\  *
> *   San Francisco State University     | ) )  /  | _ |  \      *
> *   1600 Holloway Ave.                 |)   )/   || ||   \     *
> *   San Francisco, CA   94132          | )   )   ||_||    \    *
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> 
> 
> 

Ticket Details
===================
Ticket ID: WYC-198714
Department: Support IDV
Priority: High
Status: Closed