Rainfall too low

[RayProudfoot]

Strange isn't it, I'm thinking is my rain gauge faulty? This year so far hasn't even appeared in my top 10 at 748.5 mm. In tenth place at the moment is 2020 with 807 mm.

Hi Mark. After several hours of steady overnight rain my station has recorded 17.3mm. The one in Handforth 15.5 but you’re showing 10.2mm.

I think you do have an under-recording problem.

[mcrossley]

Next rain free day I'll check the calibration...

[RayProudfoot]

Next rain free day I'll check the calibration...

Look forward to see your results. Tomorrow looks okay.

[mcrossley]

Calibration checked and it was around 30% low I reckon.

All looked OK apart from the bottom shaft for the counterweight was encrusted in rust - strange as they use a stainless-steel shaft for the main pivot. I guess the rust was adding some extra weight.

Anyway, I've recalibrated it for now, but I think I'll order a replacement tipping spoon unit and give that a go. The bucket tipper is 20 years old, so it hasn't done too badly.

[RayProudfoot]

Hi Mark, you confirmed what I suspected. Any plans to run a script to increase your daily readings?

I’m pretty sure your rainfall record will be broken.

[mcrossley]

I need to do some analysis of my data. The calibration has probably slowly changed over time, I need to try and do some comparisons.

[RayProudfoot]

I need to do some analysis of my data. The calibration has probably slowly changed over time, I need to try and do some comparisons.

When my console went crazy two years ago because I had the new ISS on the same channel as the one it replaced I had several days of mega-rainfall totals.

By taking the average of daily rainfall from several sites around me I managed to edit the bad records into something fairly close to actuals. That's where WU can come in very handy. Good luck!

[AndyKF650]

I have been watching this conversation for a few days and can confirm that the new VP2 single side rain bucket from Prodata works well. I upgraded mine in August and it has not stopped raining since

My annual rainfall has today gone past my 10 year record at 825mm with 225mm in November. I am sure there will be more rain in December so it will be interesting to see just where the total gets to.

[RayProudfoot]

Mark, your 762mm for 2023 is 40% lower than my 1069mm. It will be interesting to see what the under-recording rate is once you’ve done some analysis.

[mcrossley]

I split these posts out of the records thread as they weren't relevant there.

Ray, I know you keep your data in an Access database, could you extract your total daily rainfall for each day of 2023 for me please?

CSV format would be great: "date","rainfall"

No, rush.
Thanks

[mcrossley]

Oh, and a new Spoon tipper went in today for new year.

I checked the calibration before fitting it. Shocking, about 30% overreading, I see many people on the WX forum reporting theirs over-read from new as well (with the very odd under-reading). It seems either the Davis factory calibration of these devices is poor, or it changes in transit.

[Mapantz]

Oh, and a new Spoon tipper went in today for new year.

I checked the calibration before fitting it. Shocking, about 30% overreading, I see many people on the WX forum reporting theirs over-read from new as well (with the very odd under-reading). It seems either the Davis factory calibration of these devices is poor, or it changes in transit.

That was exactly my experience, and I tried 3 of them. On day's where 15 - 25mm would fall, the Davis tipper would always be miles out from my other gauges. I reported it to Davis several times, and even the owners of the shops that I bought them from. Of course, it fell on deaf ears as the responses that came back had an air of "Davis products are never wrong" about them.

I gave up with it and went back to the see-saw tipping bucket.

[HansR]

I have a Hellmann rainmeter to calibrate the rainmeter. I do that about 12 times per year and get a line that way. If it is within a few percent of the digital measurement I take that for true. It always keeps me alert on large deviations

[RayProudfoot]

I split these posts out of the records thread as they weren't relevant there.

Ray, I know you keep your data in an Access database, could you extract your total daily rainfall for each day of 2023 for me please?

CSV format would be great: "date","rainfall"

No, rush.
Thanks

I’ll create the query this evening and run it tomorrow Mark. I felt the spoon mechanism might be over-reading slightly but when comparing my readings on WU to nearby stations they seemed pretty close. Maybe my tipping one was under reading. I have no means of measuring by other means so I place my trust in Davis.

[mcrossley]

Thank you.