Trixology
WeatherCat => WeatherCat General Discussion => Topic started by: idunn on October 08, 2016, 02:48:28 PM
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Hi folks,
Was having a look at my rainfall and noticed something strange. How can the daily rain go up when the rain rate is still zero? See the attached graph.
Regards, Irving
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Dear Irving and WeatherCat rain watchers,
Was having a look at my rainfall and noticed something strange. How can the daily rain go up when the rain rate is still zero? See the attached graph.
That's perfectly normal and is a result of the limitations of the rainfall rate that you can compute with a rain bucket styled gauge. Here is the wikipedia explanation about it:
https://en.wikipedia.org/wiki/Rain_gauge#Tipping_bucket_rain_gauge (https://en.wikipedia.org/wiki/Rain_gauge#Tipping_bucket_rain_gauge)
Basically the problem is that it takes 2 tips of the rain buckets to compute a rate of rain falling. If too much time passes between bucket tips, it is impossible to distinguish between isolated showers and a very slow rate of rainfall. According to my old Davis station manual, the rain gauge can only measure 0.04"/hr or 1mm/hr and that's with a possible 5% error. The first 2 bucket tips on your graph are more than 1 hour apart so the station is reporting the data within the precision of the Davis instruments.
I hope that explains it.
Cheers, Edouard [cheers1]
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Edouard,
Sure should have thought of that. The second tip is necessary to get the delta time. It was a very light rain. Wishing you some rain there. Thanks, Irving
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Dear Irving and WeatherCat drought watchers,
Wishing you some rain there.
Well the forecast models have been waffling back and forth as appears to be their normal practice, but there is increasing confidence for a significant change in our weather pattern at the end of the coming work week. The unfortunate caveat is that the current forecast is for a significant storm with a period of heavy rainfall. While that will certainly remove all the dust that has been accumulating since May, it will definitely be rough on the parched soils.
I've added checking the storm drains to my "do-to" items for the week.
So thanks for the wishes! (http://www.canebas.org/WeatherCat/Forum_support_documents/Custom_emoticons/rain_happy.gif) I'm just hoping for everything in moderation!
Cheers, Edouard [cheers1]