plotting wind barbs from station data

[Dan Leins]

List,
 Please disregard - I simply defined U to be -speed*sin(theta), and V to be
-speed*cos(theta), and it works fine. Aside from a little confusion in how
perl computes trigonometric functions, it worked out.
 Dan

---------- Forwarded message ----------
From: Dan Leins <theedge981 at gmail.com>
Date: Sep 22, 2005 1:39 PM
Subject: plotting wind barbs from station data
To: GRADSUSR at list.cineca.it

 List,
 I have a script that pulls wind speed and direction out of selected METAR
files, and I would like to plot wind barbs from this data within GrADS.
However, when I 'set gxout model', and 'd spds;dirs' - I get wind barbs that
are either out of the south or west (depending on which I put 1st, spds, or
dirs), and the magnitude of the wind barb is actually drawn up as the wind
direction. So earlier today when I tried to make this plot, I all of my
sites were showing wind out of the west at 200-250 knots (wind direction was
varying from 200-250, with speeds around 10 kts). Is there a way I can use
the data I am pulling out to plot wind barbs that are representative of
current conditions, or is there a way that I can calculate the individual u
and v components of the wind at each of my points for a given wind speed and
direction? I've yet to come across a formula to break a wind speed and
direction into individual components, so if this could be done and someone
knows how to do so, I'd appreciate it!
 Thanks,
Dan Leins
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