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Graph: Wind Speed

Posted: Thu 01 Mar 2018 2:44 pm
by Altocumulus
Is there a bug in the wind speed graph?. From inspection it appears the average speed lags behind the gusts.

Yellow trace on attached graph.
Untitled-1.png

Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 2:57 pm
by PaulMy
Gusts are instantaneous while average is over a period of time so includes all the lower and higher of that period. I think the graphs look fine.

Enjoy,
Paul

Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 2:58 pm
by mcrossley
It will, it's an average of the previous 10 (default) minutes. Until a gust occurs it will cannot be included in the average, but it will affect it for the next 10 minutes.

Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 3:18 pm
by Altocumulus
Thanks guys, but that's not how the Met Office analyses anemographs - or not how they used to!
A gust was analysed within a band of 10 minute averages.

Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 3:47 pm
by mcrossley
Maybe, but for a PWS viewing 'live' data you cannot see what the wind speed will be in future to display the average speed 'now'.
If you are analysing historic data you can take a period centred on the current time.

Looking at my data it doesn't seem to lag as much as yours. What averaging period are you using? And is Cumulus or your station calculating the average?
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Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 3:51 pm
by Altocumulus
Thanks Mark - Cumulus is doing the averaging, and at 10 minute interval.

I guess it's the difference between the old fashioned anemograph analysis, and the electronic averaging.

I'd better gloss over it !

Re: Graph: Wind Speed

Posted: Thu 01 Mar 2018 4:19 pm
by sfws
The FAQ does mention divergence from met O practice http://wiki.sandaysoft.com/a/FAQ#What_d ... tations.3F

Re: Graph: Wind Speed

Posted: Fri 02 Mar 2018 7:44 am
by Altocumulus
sfws wrote:The FAQ does mention divergence from met O practice http://wiki.sandaysoft.com/a/FAQ#What_d ... tations.3F
Thanks....