# What is the accepted measure for Wind Coherency (Strength and Direction)

I have wind data from a Met station (Speed and Direction), and I'm looking for a way to characterize a strong coherent wind.

AKA - Wind that averages 12 m/s out of the East for 2 days would have a different (higher) value than a 12 m/s wind that comes from multiple directions for 2 days. Is there an accepted method for this? If so, how is it calculated?

• Don't know one... not sure why a varying direction wind be particularly significant to most people/circumstances, but ok. Would you consider a 12 m/s wind from continually varying directions to be more coherent than a 9 m/s wind consistently out of the east? Also how much of a angle change is significant... is a 10° change in direction very important? How about 15° (NNE vs NE?)? 45° (NE vs E)? How much/long of an abatement in speed reduces the score? Narrowing down your thoughts may help give a direction, though it seems anything may be fairly subjective in the end :-( – JeopardyTempest Jan 9 at 5:02
• Thanks for the input- I realize there is the danger of biasing my results here, which was why I was seeing if there was a standardized way of measuring this. As far as a significant change in direction, I would be interested on the order of 45 degrees. – Vint Jan 9 at 5:25
• The only thing that comes to mind is the Wind Rose or Wind Rosette. They are a way of graphically displaying prevalent wind directions & wind strength. The ones I've seen have usually been created from measurements taken over a considerable length of time. From ; memory, I think they are produced for certain times of the day (0900 & 1500) & for season; so Spring 9am or Winter 3 pm. – Fred Jan 9 at 8:08