Sandaysoft

In temperate latitudes, a plot of wind directions generally looks like a sine wave for much of the year as the succession of anticyclones moves through (and here the frequency of the wave is often 7 days, sometimes leading to a long succession of wet weekends!)

However, that doesn't mean that we get the same amount of wind from all directions - I hardly ever notice easterlies here, presumably because they are light. I'm developing some code to do secondary analysis of the data gathered by cumulus, and was wondering about generating some sort of weighted wind direction to help determine prevailing winds (for placement of windbreaks etc.)

One thought is to set a threshold (possibly 10km/h or 20km/h) and only plot directional frequency for higher speeds. This eliminates the random swirlings of lighter breezes.

The other is to total speeds rather than readings for each direction.

Is there any standard approach to this?

Richard

This is effectively what Cumulus does to calculate its 10-minute "average" direction (i.e. it uses vectors). I would assume that the procedure is valid for longer periods, but I don't know if that's actually what the various meteorological organisations do when publishing their predominant wind data.

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Steve
Sanday Weather
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