[ncl-talk] A special kind of plot: Earth's cross section with atmospheric data around it

[Dave Allured - NOAA Affiliate]

Tabish, with some effort it should be possible to make a concentric circle
plot using primitive plot methods within NCL.  However, there may be some
specific high level functions that could do this more easily.  Check out
the polar stereographic examples, specifically polar_8.ncl.  The trick is
after your zonal averaging, to convert the height dimension into a fake
latitude dimension which is the radial dimension in the desired plot.

To omit the wind vectors, use the *gsn_csm_contour_map_polar* function in
place of *gsn_csm_vector_scalar_map_polar*.  The inner and outer circle
diameters may be controlled by subsetting the fake latitude dimension, as
shown in the example code.  I have not tested this, not sure you can get it
to work with the substituted latitude dimension.

[image: image.png]


On Tue, Jan 27, 2026 at 2:21 PM Tabish Ansari via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Dear NCL community,
>
> I hope that you're doing well and still using the good old NCL from time
> to time in the era of Python and vibe coding.
>
> I have a particular kind of plot in my mind which, if realised, could
> illuminate some of the atmospheric processes that I want to investigate,
> very well. I have 4D data (time, vertical_lev, lon, lat) for tropospheric
> ozone emanating from different world regions from a global model output
> over a certain period. I'm mainly interested in its intercontinental
> transport and mixing in the mid-latitude zone (30-60 degrees N). So, I want
> to cut the globe across these latitudes and take an average across this
> latitude zone and plot the ozone in a circular fashion which wraps around
> the inner circle (representing the Earth). So the plot is supposed to show
> two concentric circles and the ozone values plotted as color-filled
> contours within the two circles. Here the inner circle is the Earth and the
> outer circle could be, say, the tropopause. I'm intending to make these
> plots for ozone emanating from different sources shown in different colors
> and opacity and overlay them at each time frame and produce these images
> for all times and ultimately create an animation with them which shows the
> intercontinental ozone transport and mixing. Are there any special NCL
> functions I can use to create this kind of a concentric circle contour
> plot? If so, please let me know.
>
> Thanks a lot!
>
> Cheers,
> Tabish
>
> --------------------------------------------------------------------------------------
> Dr Tabish Ansari
> Research Associate
> Air Quality Modelling Group
> Research Institute for Sustainability (RIFS) - Helmholtz Centre Potsdam
> Potsdam, Germany
>
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