Rain measurement: Difference between revisions

The tipping bucket gauge consists of a funnel that collects and channels the precipitation. The precipitation falls onto one of two small buckets or levers which are balanced in same manner as a balance scale.  

Tipping gauges can incorporate weighing gauges. In these gauges, a strain gauge is fixed to the collection bucket so that the exact rainfall can be read at any moment. Each time the collector tips, the strain gauge (weight sensor) is re-zeroed to null out any drift.

In the more common design, when the bucket fills sufficiently to "tip" the balance an electrical signal is sent to the recorder.  Modern tipping rain gauges consist of a plastic collector balanced over a pivot. When it tips, it actuates a switch (such as a [http://en.wikipedia.org/wiki/Reed_switch reed switch]) which is then electronically recorded or transmitted to a remote collection station. Counting tips is not as accurate as the standard rain gauge because the rainfall may stop before the lever has tipped. When the next period of rain begins it may take no more than one or two drops to tip the lever. Tipping buckets tend to underestimate the amount of rainfall, not collecting all of it, particularly in snowfall and heavy rainfall events. Tipping buckets can be subject to vibration if not securely mounted causing the balance to tip resulting in a false rain measurement.

The advantage of the tipping bucket rain gauge is that the rain rate may be easily obtained. Rainfall rate is decided by counting the number of 'clicks' in a short fixed period and lets the observer decide the character of the rain.