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Rainrate mm/h


Makada Sep 29, 2017 06:05 PM

Hi all,

i would like to have the rainrate in mm/h

someone got an example how to do achieve this?

id like to have it in realtime and a max for the day and a reset after lets say 10 minutes after the rain.

(PulseCount(Rain_mm,1,1,2,0,0.2,0))


JDavis Sep 29, 2017 07:08 PM

When doing rainfall intensity calculations, you have to decide on the integration interval. Instantaneous rainfall intensities calculated on 1 second intervals would appear very spiky. A tipping bucket rain during light rain could show 0 rainfall for 59 seconds, then a really high intensity for 1 second. Enough rain had to accumulate in the bucket to tip it. You need to decide an appropriate interval to average out the spikes.

The combination of how long you average along with the resolution of your raingauge determines the resolution of your intensity.

Examples:

If you have a 0.1mm per tip rain gage and average intensity over 1 minute

    0.1mm/1min * 60min/hr = 6mm/hr resolution

The same rain gage averaged over 60 minutes

    0.1mm/60min * 60min/hr = 0.1mm/hr resolution

You get the instantaneous intensities by multiplying your rainfall times the scans per hour.

     Rain_mmHr = Rain_mm*scans/hr  (a 1 second scan is 3600 scans per hour)

Use the AvgRun instruction to average the intensity.


Makada Sep 30, 2017 06:32 PM

Thanks for the reply. 

I found this post,  although i dont know what "sint" is in "Scan(Sint,Sec,0,0)"

My program is "Scan(1,Sec,1,0)"

https://www.campbellsci.com/forum?forum=1&l=thread&tid=616


Makada Oct 3, 2017 08:33 AM

Im still not able to get it working.

The thing is, i think i need a kind of timer that measure the time in between the tips, and a reset of that value after it stopped raining...(and start the timer when the First tip is recorded......)

As far as i know is the tipping bucket currently in use not connected to a control port.


JDavis Oct 3, 2017 03:20 PM

In the other example you saw, Sint is a constant for the number of seconds that is the scan rate.

The timer method only works with a fast scan rate. The number of scans between tips is your resolution.


Makada Oct 3, 2017 06:30 PM

Ok thanks.

Do you have an example regarding the timer method?

Would a 1 second scanrate be enough?

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