Re: Wind Barbs cross equator

From: David Brown <dbrown_at_nyahnyahspammersnyahnyah>
Date: Thu May 20 2010 - 11:32:56 MDT

Hi,

Unfortunately, the NCL VectorPlot object does not currently
automatically change the wind barb tick position to account for the
conventional difference for north and south of the equator. You can
manually change the resource vcWindBarbTickAngleF to a negative value
to get wind barbs that conform to the southern hemisphere convention.
(The default is 62.0 so you could set it to -62.0 to get mirror imaged
southern hemisphere wind barbs.) However, this does not help for plots
that cross the equator where both conventions are needed. We can add
the automatic recognition of hemisphere to the to-do list.

In the meantime, as a work-around it should be possible to draw the
wind barbs in 2 phases as two separate overlay plots, masking out
first the southern and then the northern locations. If you can send
us your data set or point us to a location where we can get it we
could possibly make an example for you. Instructions for uploading
files can be found here: http://www.ncl.ucar.edu/report_bug.shtml
  -dave

On May 20, 2010, at 12:42 PM, waniha@meteo.go.tz wrote:

> Dear all,
> I have tried to re-edit script from wrf-website to get mslp and wind
> barbs, there's nothing wrong with the pressure, but I am getting some
> problems with winds;
> 1. The Fins are plotted as if the wj=hole domain is in the northern
> hemisphere,
> 2nd Although the domain crosses the equator but the wind barbs does
> not
> change fins direction across the while crossing equator,
> Any help will be appreciated
> enclosed herewith this mail please find the script and produced
> image
> <
> surface
> .ncl><wind_850mlp.png>_______________________________________________
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Received on Thu May 20 11:33:03 2010

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