Re: skewt_func.ncl code

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Tue Dec 20 2011 - 10:47:06 MST

Changing the code as you indicate would be difficult.
The code is hard-wired to reproduce the "USAF Skew-t, log p diagram
(form dod-wpc 9-16-1).

As indicated in the code, some intersections are computed
and some are specified.

I think the 'trial and error' approach is the only option.
Unfortunately, I do have the time to halp with the modifed skewT.

Good Luck
===================================================================
[SNIP]
; --- declare isotherm [C] values and pressures [hPa] where isotherms
; --- intersect the edge of the skew-t diagram.

temp = (/-100.,-90.,-80.,-70.,-60.,-50.,-40.,-30. \
, -20.,-10., 0., 10., 20., 30., 40., 50. /)
lendt= (/ 132., 181., 247., 337., 459., 625., 855. \
,1050.,1050.,1050.,1050.,1050.,1050.,1050.,1050.,1050./)
rendt= (/ 100., 100., 100., 100., 100., 100., 100. \
, 135., 185., 251., 342., 430., 500., 580., 730., 993./)
ntemp= dimsizes (temp) ; isotherms
if (dimsizes(lendt).ne.dimsizes(rendt) .or. \
dimsizes(lendt).ne.ntemp) then
print ("Error: dimsizes temp, lendt, rendt do not match")
exit
end if

; --- declare pressure values [hPa] and x coordinates of the endpoints
of each
; --- isobar. these x,y values are computed from the equations in the
; --- transform functions listed at the beginning of this program.
; --- refer to a skew-t diagram for reference if necessary.

pres = (/1050.,1000.,850.,700.,500.,400.,300.,250.,200.,150.,100./)
xpl = (/-19.0,-19.0,-19.0,-19.0,-19.0,-19.0,-19.0,-19.0 \
,-19.0,-19.0,-19.0/)
xpr = (/27.1,27.1,27.1,27.1,22.83,18.6,18.6,18.6,18.6,18.6,18.6/)
npres= dimsizes (pres) ; pressures
if (dimsizes(xpl).ne.dimsizes(xpr) .or. dimsizes(xpl).ne.npres) then
print ("Error: dimsizes pres, xpl, xpr do not match")
exit
end if

; --- declare adiabat values [C] and pressures where adiabats intersect the
; --- edge of the skew-t diagram. refer to a skew-t diagram if necessary.

theta= (/-30.,-20.,-10.,0.,10.,20.,30.,40.,50.,60.,70.,80.,90. \
,100.,110.,120.,130.,140.,150.,160.,170. /)
lendth= (/880.,670.,512.,388.,292.,220.,163.,119.,100.,100.,100. \
,100.,100.,100.,100.,100.,100.,100.,100.,100.,100. /)
rendth= (/1050.,1050.,1050.,1050.,1050.,1050.,1050.,1050. \
,1003.,852.,728.,618.,395.,334.,286., 245., 210. \

[SNIP]
======================================================================

On 12/20/2011 10:21 AM, Manisha Ganeshan wrote:
> Hi,
>
> I am trying to modify the skewt_func.ncl code to be able to plot one
> from my sounding data.
> I noticed that the skewt_func.ncl file has these values hardwired into
> the code. For example, dry adiabat values are declared as potential
> temperature values at 1000hPa level. The points where these intersect
> the left and right edge of the skewt (y-axis) are also declared. Do you
> know how these values are calculated?
>
> For example, I want to plot one additional adiabat say with potential
> temperature 32 degrees C at 1000hPa, but I don't see how can I determine
> the value of the intersection of this adiabat exactly at the y-axis
> (edge of the skewT).
>
> Kindly help.
>
> Nisha
>
>
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Received on Tue Dec 20 10:47:16 2011

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