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Wind Definitions

Posted: Mon 04 Apr 2011 6:45 pm
by Sunfish
Cumulus has several readings for "wind".
These are, latest, average, gust, high gust and high wind.

I assume that 'average' is a 10 minute reading, but what is 'high wind'?

Generally, what do 'official' weather readings use to measure wind.

Thanks

Re: Wind Definitions

Posted: Mon 04 Apr 2011 8:19 pm
by steve
For Davis stations, 'latest' is the most recent 3-second wind speed reading. 'Average' is the average of those readings over the last 10 minutes, which is the same as the station itself supplies, so you shouldn't see any difference in that value whether you get Cumulus to calculate it or not. 'Gust' is the highest of the 'latest' values over the last 10 minutes. 'High wind' is the highest today/yesterday/etc of the 'average' figures, and 'High gust' is the highest of the 'gust' figures.

There aren't any universally adopted standards for wind speeds, but generally 10 minutes is the period typically used (although sometimes 2-minute speeds are used). When the UK Met Office warn of Force 9 gales (e.g. in the shipping forecast), it's the 10-minute average that they're referring to.

Re: Wind Definitions

Posted: Mon 04 Apr 2011 9:12 pm
by Sunfish
Interesting and helpful, thanks.

But 'official' stations like the Met Office, BBC, quote wind speeds that are consistently (quite a bit) higher than my data. Whilst my anemometer is not 30' up a pole, readings compare well with all nearby stations.

Re: Wind Definitions

Posted: Tue 05 Apr 2011 8:40 am
by steve
Yes, it's a problem that most 'back garden' sites will have; poor exposure and lack of height, compared to official stations.