(Lagos - Nigeria)
Wind Rose Example
HOW DO ONE DRAW A WIND ROS AND what is the function of these wind diagrams?
Barry's Response - Kelvin:
A wind rose is a plot that shows a breakdown of wind speeds and directions, based on a compass-style plot, gathered at a monitoring site. The data plotted represents a frequency distribution of wind speeds and directions observed over a certain period of time such as a month or a year, at a single point on the earth. And this data is plotted using a polar coordinate system. As you can see in our example above, the most frequent wind direction observed at this site is from the northwest, with west-northwest in second place.
The windrose is a radial graph with a unique appearance, crudely resembling a flower, thus the name. Note the colours. Each one represents a narrow range of speeds, and you can see the ranges in the legend. Note, also, the concentric circles drawn in the background. Each one represents a percentage of time over the data-observation-period that the wind blows from that particular direction, with increasing percentages as you go further from the centre.
Air quality meteorologists use this data to gain a quick overview of the pollution distribution characteristics expected for a site. Aviation engineers use them to design airports, knowing that planes prefer to take off and land into the wind whenever possible.
If you have the wind data, software for creating the wind diagrams can be downloaded and run for creating a wind rose for free by submitting an email address at http://www.weblakes.com/
Look down the left and under "downloads" select "WRPLOT View".
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