[ncl-talk] mean sea level pressure plot

[Adam Phillips]

Hi Giorgia,
I think you need to change stres at cnLevelSelectionMode = "ManualLevels". If
you leave that set to "ExplicitLevels" then you would need to set your
contour levels via stres at cnLevels.

As far as noise goes, NCL does not apply any kind of smoothing to your
data. You can turn smoothing on by setting stres at cnSmoothingOn = True.

http://www.ncl.ucar.edu/Document/Graphics/Resources/cn.shtml#cnSmoothingOn
(Note that there are other resources cited that control the degree of
smoothing.)

Alternatively, you can smooth the data yourself using, for example,
smth9_Wrap:
https://www.ncl.ucar.edu/Document/Functions/Contributed/smth9_Wrap.shtml
(I use smth9_Wrap so that I know exactly how the data is being smoothed.)

Hope that all helps. If you have any further questions please respond to
the ncl-talk email list.
Adam


On Mon, Sep 8, 2014 at 12:08 PM, <giorgia.verri at cmcc.it> wrote:

> Dear ncl,
> find enclosed a latlo nmap of 500hPa geopotential height and isolines of
> mean sea level pressure. I used "gsn_csm_contour" to plot isobars but I
> have 2 problems:
> 1) isolines show noise
> 2) I selected minlevel, maxlevel and levelspacing in the ncl script but
> those in the picture are different.
> I also attached the ncl script I wrote for plotting
> Thanks
> Cheers
> Giorgia
>
>
>
>
>
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-- 
Adam Phillips
Associate Scientist,  Climate and Global Dynamics Division, NCAR
www.cgd.ucar.edu/staff/asphilli/   303-497-1726

<http://www.cgd.ucar.edu/staff/asphilli>
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