Odd rainfall reading
Posted: Sun 01 Dec 2019 4:22 pm
This is odd; this morning Cumulus showed me a rainfall total of 94mm occuring within a 30 minute period, yet the rainfall rate was flat, no spikes. I stopped Cumulus in order to start the Weatherlink software - that and the console agreed on a 0.4mm rainfall occuring at that time. Just in case I pulled the sensor and checked that it was clean, as was the funnel.
I use the Davis Weatherlink IP data logger to read data from the console (at 10Mbps - I didn't think anything ran that slowly these days!). Can anyone explain this anomaly? Normally my readings match quite closely with a VP2 station a couple of miles from here but not this time...
Here's the relevant extract from today's log:
01/12/19,10:10,5.3,90,3.8,1,4,68,0.0,0.0,1022.79,0.0,18.2,56,4,5.3,5.3,0.0,0,0.00,0.00,3.7,126,0.0,67,0.0,0.0
01/12/19,10:20,5.5,90,4.0,1,5,68,0.0,0.2,1022.93,0.2,18.2,56,5,5.5,5.5,0.0,0,0.00,0.00,3.9,136,0.0,67,0.0,0.2
01/12/19,10:50,6.2,89,4.5,1,3,72,0.0,93.8,1022.96,93.8,18.1,56,1,6.2,6.2,0.0,0,0.00,0.00,4.7,160,0.0,77,0.0,93.8
01/12/19,11:00,6.3,89,4.6,2,6,65,0.0,93.8,1022.96,93.8,18.1,57,1,6.3,6.3,0.0,0,0.00,0.00,4.5,166,0.0,65,0.0,93.8
I my maths is anywhere near accurate 94mm is close to 400 tips, that in 30 minutes should have produced an enormous rain-rate spike but as mentioned, the Cumulus graph for that shows a rate of zero for that period.
Davis Vantage Vue (UK spec, 0.2mm tipping spoon)
Any ideas? At the moment I'm kind of discounting mechanical accuracy as the Davis is only a month old. I also had to start with a fresh Cumulus install at the time because my old FO station had misbehaved so much that the entire data set was useless.
I use the Davis Weatherlink IP data logger to read data from the console (at 10Mbps - I didn't think anything ran that slowly these days!). Can anyone explain this anomaly? Normally my readings match quite closely with a VP2 station a couple of miles from here but not this time...
Here's the relevant extract from today's log:
01/12/19,10:10,5.3,90,3.8,1,4,68,0.0,0.0,1022.79,0.0,18.2,56,4,5.3,5.3,0.0,0,0.00,0.00,3.7,126,0.0,67,0.0,0.0
01/12/19,10:20,5.5,90,4.0,1,5,68,0.0,0.2,1022.93,0.2,18.2,56,5,5.5,5.5,0.0,0,0.00,0.00,3.9,136,0.0,67,0.0,0.2
01/12/19,10:50,6.2,89,4.5,1,3,72,0.0,93.8,1022.96,93.8,18.1,56,1,6.2,6.2,0.0,0,0.00,0.00,4.7,160,0.0,77,0.0,93.8
01/12/19,11:00,6.3,89,4.6,2,6,65,0.0,93.8,1022.96,93.8,18.1,57,1,6.3,6.3,0.0,0,0.00,0.00,4.5,166,0.0,65,0.0,93.8
I my maths is anywhere near accurate 94mm is close to 400 tips, that in 30 minutes should have produced an enormous rain-rate spike but as mentioned, the Cumulus graph for that shows a rate of zero for that period.
Davis Vantage Vue (UK spec, 0.2mm tipping spoon)
Any ideas? At the moment I'm kind of discounting mechanical accuracy as the Davis is only a month old. I also had to start with a fresh Cumulus install at the time because my old FO station had misbehaved so much that the entire data set was useless.