Our full technical support staff does not monitor this forum. If you need assistance from a member of our staff, please submit your question from the Ask a Question page.

Log in or register to post/reply in the forum.

TB4MM rain gauge overestimating precipitation

ajinkyagd Jun 29, 2022 08:13 PM

A TB4MM rain gauge is installed in Sri Lankan tropical forests. It was recording rainfall accurately initially after installation. After monsoon rains began, the rain gauge started measuring unrealistically high numbers (7000 mm/month) with the same CR3000 program running. It rains about 2500 mm annually at the site. 

CR3000 program:

'TB4MM Tipping Bucket Rain Gauge measurement 'Rain_mm' PulseCount(Rain_mm,1,1,2,0,0.2,0) 'TB4MM S/N: 20-333, Calibration Factor = 0.2 mm per tip
TotalRun (Rain_TotalRun,1,Rain_mm,100,False)

Any help would be greatly appreciated!

smile Jul 2, 2022 04:01 AM

It often happens that in incorrect installations, the rain gauge moves or vibrates due to the wind, also generating the oscillations of the tilting trays.

Check the cable anyway and do the test with a known quantity of water e.g. one liter to be poured into the funnel in 2 or 3 minutes and record the counts.

Then relate the amount of water used for test to the diameter of the funnel to find out how many mm of rain you will have had to record.

I do not think that very intense rains, beyond the specifications of the rain gauge, can generate a frequency of oscillation of the receiver that is too high, such as to generate false measurements, i.e. the receiver begins to run too fast and the spoons do not fill completely.


Log in or register to post/reply in the forum.