Wind gust line / Data logger

[Truscom]

Another newbie question, thank you to all that help in advance!
I turn my computer off each night and then on again in the morning and when the data is uploaded the wind gust and average are the same. I read the FAQ and I do have the 10 min average ticked and the data logger was set at 10mins so I changed the data logger to be one minute, thinking this would fix it. But it hasn't?
I have also read a forum posting from 2010 where someone is advised that if you want the wind gust line then you have to uncheck the 10min average. I am confused as I though having the data logger set to one minute would stop the problem. If this problem is fixable, can I go back and get this mornings data to reload?
Thanks in advance.....

[steve]

You can't have set the station's data logger to 1 minute; it has a minimum interval of 5 minutes. If you set it to 5 minutes (using easyweather) then you should get two distinct lines plotted even if you have Cumulus set to calculate the average (since each average will be taken from two values in the logger). Whether that's actually useful, given that only two values contribute to the average, is another matter.

[AllyCat]

the wind gust and average are the same......
I read the FAQ and I do have the 10 min average ticked and the data logger was set at 10mins

Hi Martin,

Do you also have the "use speed..." box ticked? Read the Help : Station settings within Cumulus and you will find that unless that box is also ticked, Cumulus will record the peak gust and the "average of gusts" from the logger, NOT the average wind speed. IMHO (at least for FO stations) Cumulus would be more "idiot proof" (no disrespect, I made the same mistake) if the two flags ("..average.." and "..speed.." HAD to be set the same. I don't understand the mathematical significance of calculating/recording an "average of peaks".

Cheers, Alan.

[steve]

IMHO (at least for FO stations) Cumulus would be more "idiot proof" (no disrespect, I made the same mistake) if the two flags ("..average.." and "..speed.." HAD to be set the same.

No, that wouldn't make sense, it wouldn't give people the option of using either the FO 'gust' or FO 'wind' for the calculation.

I don't understand the mathematical significance of calculating/recording an "average of peaks".

That's as may be, but as I said before (many, many times!), empirically, many people find that with Fine Offset stations, calculating the average wind speed using what Fine Offset call a 'gust' gives a more realistic figure than using the mean speed that the station calculates. We're not dealing with high quality expensive equipment here. People have gone to all kinds of lengths to try to make these things 'punch above their weight'.

I carried out tests comparing the speeds calculated from my Fine Offset 'gust' and 'wind', with the average speeds from my Davis VP2, and unless the wind conditions were particularly 'gusty', the gust-based calculation was much closer to my VP2 figure than the wind-based calculation.

[AllyCat]

as I said before (many, many times!), empirically, many people find that with Fine Offset stations, calculating the average wind speed using what Fine Offset call a 'gust' gives a more realistic figure than using the mean speed that the station calculates. .

Thanks Steve,

Sorry, as a relative newbie I'd missed those earlier observations. My comments were based on this thread where I thought the conclusion was that I'd made the "mistake" of NOT setting the speed flag.

I carried out tests comparing the speeds calculated from my Fine Offset 'gust' and 'wind', with the average speeds from my Davis VP2, and unless the wind conditions were particularly 'gusty', the gust-based calculation was much closer to my VP2 figure than the wind-based calculation.

Yes, I must admit that I thought that my wind readings were unusually low, but assumed it was because I'm located in an urban area. But, if the "gust" is a better value to use, then returning to my previous thread above, how can I get Cumulus to report an "accurate" wind run (since it appears to use the FO "average" value)? [Rhetorical question as I guess I can't].

Cheers, Alan.

[steve]

But, if the "gust" is a better value to use, then returning to my previous thread above, how can I get Cumulus to report an "accurate" wind run (since it appears to use the FO "average" value)? [Rhetorical question as I guess I can't].

I changed the code not long after that thread so it uses the calculated value for wind run if the 'calculate...' option is set. Apologies if I didn't announce this; I don't always remember to list every change that I've done.