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Rainrate - again

Posted: Wed 11 Aug 2010 3:28 am
by serowe
Steve - I read your replies in other threads about the Rainrate. I have noticed that in my data the rain rate doesn't appear to get incremented until another mm of rain is recorded. ie I can have 1 mm recorded for some hours, as soon as another mm hits the gauge and Cumulus, the rainrate becomes 1.0.

I am using a WM918 - so is this figure coming from the station (I note you said previously that you get the figure from the station but this implies the WM918 is included, but not confirmed) or from calculations? Obviously with V2 taking priority, what will the sc=enario for rainrate be in the new version?

This issue doesn't appear to have happened from my FreeWx files eg:

10 Feb, 2007 14:42 1010 19.6 80.0 16.1 26.2 41.0 7.2 SW 5.8 0.0
10 Feb, 2007 14:52 1010 19.1 86.0 16.7 26.3 42.0 6.1 SSW 11.9 5 34.0
10 Feb, 2007 15:02 1011 18.7 87.0 16.5 26.2 43.0 5.0 SE 5.0 7 11.0
10 Feb, 2007 15:12 1010 19.0 87.0 16.8 26.2 43.0 4.3 ESE 7.2 7 11.0
10 Feb, 2007 15:22 1010 19.0 86.0 16.6 26.2 43.0 4.0 SE 6.5 7 11.0

Last column is rain rate and 2nd last column rain recorded for the period.

Re: Rainrate - again

Posted: Wed 11 Aug 2010 7:51 am
by steve
Yes, with the WM918, the rain rate is provided by the station. 1 mm is one tip of the bucket. You can't calculate a rate from one tip, so the station's rain rate doesn't go above zero until two tips have been recorded within a set interval. I think the interval the WM918 uses is two hours.