Wind roses are used to present wind speed data and wind direction data that have been collected over time, so that the dominant wind pattern for a particular area can be determined. Wind roses are also useful as they project a
large quantity of data onto one graphical plot. The length of each ‘arm’ is proportional to the
amount of time for which that wind speed was observed from that direction. The different colours on each arm indicate the wind speed. For example, in the wind rose in Fig. 22 most winds came from the south to south-west as indicated by the length of the two longest arms. Winds with higher wind speeds came from the west and south-west as indicated by the orange at the end of the arms.
SKILLS EXERCISE
In Fig. 22 calculate the percentage of days with wind speeds between 3–6 metres/second from the south-west.
254 % WIND ROSE
20 15 10 5 0 5
10 15 20
Fig. 22 A wind rose 0.5 Birr 8.9 3.3 Dublin Airport 4.8 Malin Head 0.8