Accuracy of the Haptic Rain Sensor
Rain Accumulation values are calculated over a 24 hour period from midnight to midnight using the station's local time. Be cautious when comparing rain accumulation readings to other sources as collection times may differ and rain does not fall evenly across regions, towns or even neighborhoods.
A default calibration is used for haptic rain sensors in the Tempest and SKY devices. The haptic rain sensor detects and quantifies rain using vibration signals - not directly by volume or weight. There are many factors that can influence vibration signals. Each and every haptic sensor in the field is subject to unique external factors that can contribute to accumulation discrepancies, for example, mount materials, mast height, environment, wind, and turbulence can all affect the resulting rain accumulation readings.
When well sited and calibrated, the haptic sensor can provide a very accurate rain accumulation (90-100% accuracy in Tempest) compared to accumulation measured by a conventional rain gauge, which should also be well sited and located in the same area as the Tempest device.
A conventional rain gauge is highly precise but a haptic sensor has many advantages as it is able to provide details on rain start time, event duration, relative intensity and rain rate at 1 minute resolution. Not to mention there is no need for the user to manually empty collected rain and record data after each and every rain event.
A calibration adjustment can help improve accuracy of the haptic sensor readings if accumulation measurements are way outside of accuracy specifications. Due to the factors that contribute to different vibration signatures, calibrations may need to be applied in the field, after final installation. You should first ensure that your mount is sturdy and there are no external vibration contributing to over-reporting accumulation. Calibration cannot fix the effects of an unstable mount or random vibrations caused by winds, birds, etc.
If you think your device needs a calibration adjustment, we'd be happy to help. Our meteorological data science team can apply a calibration update to your devices using comparison rain data.
I have another rain gauge I can use for comparison data
Using rain accumulation data from another trusted gauge sited close by is by far the best method to re-calibrate with successful results. Please send us the comparison data, 24 hour rain accumulation (from midnight to midnight local time).
- Register your co-located gauge you are using for comparison data.
- Once registered, report individual rain events
(ideally over a 24-hour period, from 12AM to 12AM local time)
More data from a larger sample size of rain events is preferred. Submit comparison data from at least several precipitation events with varying intensity for the best results.
- Follow up with us after you think you have submitted enough reports for a decent calibration adjustment.
I do not have access to another gauge. Can I still get help with a calibration adjustment?
We can use data published online from nearby gauges and/or Rain Check values to help with calibration adjustments. If there is another trusted weather station close enough nearby that is reporting data online, we can review rain data to use as a reference for a calibration adjustment. Please contact us for assistance.