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Question about rainfall rate calculation

Discussion specific to Oregon Scientific weather stations
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kinder
Posts: 38
Joined: Mon 08 Nov 2010 5:50 pm
Weather Station: DAVIS VANTAGE PRO 2
Operating System: Windows 7
Location: Nowhere

Question about rainfall rate calculation

Post by kinder »

Hello.
For people using older oregon scientific weather stations,there is a probem with the rainfall rate,according to the manual of the weather station.
The rainfall rate reported by the station clears to zero 2 hours after the rain has stopped.Thats ofcourse a hardware related problem,but i wonder if it is possible to do something to fix the display of the rate in software basis.
I thought that if for 1 hour the rainfall ammount remains the same,then there is no rainfall occured.If thats happen then the program could reset rainfall rate to zero,and keeps a record of the previous rate.If the rate has changed to something else than zero,new rainfall rate occured.
I don't know if that solution can be done easily,but for some oregon users maybe a nice feature if it is done ok.
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steve
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Posts: 26702
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
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Re: Question about rainfall rate calculation

Post by steve »

I never really saw that as an issue when I used my WMR928. The problem is that it's difficult to determine whether it's actually still raining or not with a TBR, particularly one that has a large 'tip' such as the WMR928 (etc), so I guess this is why they chose the 2 hour period. But I agree that 2 hours is perhaps too long a period for the rate to return to zero; on Davis stations the rate returns to zero when no tips have occurred in 15 minutes - but that does have a much smaller 'tip'.

For stations which don't supply a rain rate (such as Fine Offset stations) Cumulus calculates a rain rate; but the current calculation is quite simple and needs enhancing. I have an enhanced algorithm, based on the Davis one, and I did try using it once, but there are problems using it with long logger intervals, so I gave up on it temporarily. At some point I propose to try again to get it working, and if successful I'll offer it as an alternative to the station's calculation for other station types too, such as Oregon Scientific.
Steve
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