Re: Questions about SkewT plot

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Mon Mar 10 2014 - 10:30:28 MDT

Hello,

Please read and examine:
      http://www.ncl.ucar.edu/Applications/skewt.shtml

-------

http://www.ncl.ucar.edu/Applications/skewt.shtml

[1] As noted in the documentation

It is designed to reproduce the "USAF Skew-t, log p diagram (form
dod-wpc 9-16-1).

     The USAF skew-t only goes to 100mb.

You would have to copy the code

%> $NCARG_ROOT/lib/ncarg/nclscripts/csm/skewt_func.ncl my.skewt_func.ncl

and alter the code.

[2] See Example 1

[3] CAPE calculation is somewhat sensitive to where the
     ascent is started. There are a number of CAPE codes tested
     and none agreed. There are two CAPE calculations: one by
     the WRF project and another that is included with NCL but is not
     documented.

[4] I think the easiest way to accomplish )say) every 5th wind would be
     to do something like

       uu = u
       vv = v
       uu@_Fillvalue = u@_FillValue
       uu@_Fillvalue = u@_FillValue
       uu(::5) = u(::5)
       vv(::5) = v(::5)

[5] Isn't that the adibatic lapse rate!

     Again, you would have to modify the code.

[6] When you open the work station

     wks = gsn_open_wks ("png", "skewt")

Good luck
On 3/9/14, 9:19 AM, Gökhan Sever wrote:
> Hello,
>
> I have some questions about a Skew-T Log-P plot produced in NCL. Consider
> the attached Weisman and Klemp (1982) type sounding as a reference, created
> from an idealized WRF simulation output.
>
> 1) How to set y-axis upper limit to, say 10 mb instead of the default 100
> mb?
>
> 2) How to change the green-white alternating background to white only?
>
> 3) The input data before calling skewT_PlotData are interpolated (using 100
> vertical levels instead of 50) in my case, otherwise CAPE estimation seems
> to be off by a couple hundred J/kg. However, as an artifact, there are so
> many wind barbs are plotted. Is there a way to plot barbs, say at every 5
> points?
>
> 4) How to move the barb axis or height axis so that the plot looks more
> compact? I am only interested in u-wind, so these two axes really can be
> combined.
>
> 5) What is the straight grey line ascending from in between 8-12 g/kg
> mixing ratio lines up above? Is there a way to suppress it?
>
> 6) Is there a way to save SkewT plot directly to png or jpg? It's easy to
> save in PDF, however I couldn't figure out a way to directly saving as a
> png or jpg.
>
> Many thanks.
>
>
>
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Mon Mar 10 10:30:16 2014

This archive was generated by hypermail 2.1.8 : Fri Mar 14 2014 - 15:08:52 MDT