[ncl-talk] How to plot tropopause height with units in hPa.

[Adam Phillips]

Hi Chang,
Thanks for sending the plot as now I see what you want to do.. I do not believe there is an example on the NCL website of this type of plot.  When you say the overlay did not work: can you provide details and an example plot? I would try creating the U plot (using gsn_csm_pres_hgt) and the tropopause height plot (using gsn_csm_xy) first, setting trYMinF/trYMaxF/trXMinF/trXMaxF the same for both plots, and then call overlay. 

A second option might be to create the U plot, and then draw the tropopause by calling gsn_add_polyline.

If you continue having trouble please send along a copy of your script, any error messages, and the resulting plot so ncl-talk can better assist.
Adam

> On Jul 17, 2015, at 01:20, Xi Chang <xi.chang01 at gmail.com> wrote:
> 
> Thanks Adam,
> 
> Is there any example for this in which I can plot the tropopause height (single line contour) on top the zonal mean wind (shading). I tried to use overlay but it seems to be complicated and the axis is not matched. Please find an example below using matlab.
> 
> 
>> On Thu, Jul 16, 2015 at 11:16 PM, Adam Phillips <asphilli at ucar.edu> wrote:
>> Hi Chang,
>> As you likely know there are numerous height/latitude examples here: 
>> http://www.ncl.ucar.edu/Applications/height_lat.shtml
>> 
>> If you want to overlay a zonal mean on top of a height (Y-axis) by latitude (x-axis) plot I would recommend creating each plot separately, and then using gsn_add_annotation to add the zonal mean plot to the height/latitude plot. 
>> http://www.ncl.ucar.edu/Applications/annotate.shtml
>> 
>> You will have to work on getting the amJust, amOrthogonalPosF and amParallelPosF settings correct, but it should be quite possible.
>> 
>> Using the overlay function may be another possibility but I do not believe that will work as your two plots do not share the same Y-axis coordinate values (pressure vs. U-wind values).
>> 
>> Hope that helps. If not or if you have any other questions, please respond to the ncl-talk email list.
>> Adam
>> 
>>> On Thu, Jul 16, 2015 at 11:27 AM, Xi Chang <xi.chang01 at gmail.com> wrote:
>>> Hi NCL,
>>> 
>>> I have zonal mean tropopause height data H (units: hPa) as a function of latitude (-90:90). How could I plot this values by using "gsn_csm_pres_hgt" function, so that I can overlay them with zonal mean wind U data.
>>> 
>>> Thanks for any hints.
>>> Chang
>>> 
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>> 
>> 
>> 
>> -- 
>> Adam Phillips 
>> Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
>> www.cgd.ucar.edu/staff/asphilli/   303-497-1726
> 
> <example.jpg>
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