Standard vs. Tipping Bucket Rain Gauges

Standard vs. Tipping Bucket Rain Gauges A rain gauge is a  weather instrument that gathers and measures the amount of liquid precipitation that falls from the sky. How a Tipping-Bucket Gauge Works A tipping bucket rain gauge has several components that allow it to accurately measure rainfall. As rain falls, it lands in the funnel of the tipping bucket rain gauge. The rain travels down the funnel and drips into one of two very carefully calibrated ‘buckets’ balanced on a pivot (like a see-saw). The top bucket is held in place by a magnet until it has filled to the calibrated amount (usually approximately 0.001 inches of rain). When the bucket has filled to this amount, the magnet will release its hold, causing the bucket to tip. The water then empties down a drainage hole and raises the other to sit underneath the funnel. When the bucket tips, it triggers a reed switch (or sensor), sending a message to the display or weather station. The display counts the number of times the switch is triggered. Because it knows how much rain is needed to fill the bucket, the display can calculate the rainfall. Rainfall is measured in inches; 1 of rain would fill a container with straight edges to a level of 1. Getting the Best Results From Your Rain Gauge To get the most accurate results from a tipping bucket rain gauge, you need to properly install the rain gauge. The rain gauge must be positioned on a flat surface – if the surface isn’t flat, the see-saw may tip before the bucket has filled to the calibrated level, or not tip at all. If the bucket doesnt tip at the calibrated level, the rainfall calculated will not be correct. Use a spirit level to determine whether a surface is flat, and then fix the gauge to the flat surface to ensure you are getting an accurate reading.The rain gauge must be positioned on a surface that does not vibrate – surfaces such as a porch or fence can move and vibrate. The tipping bucket is very sensitive and any vibrations could cause the gauge to tip even if it is not raining.The instrument must not be positioned near trees – being positioned near trees could allow leaves or pollen to fall inside the funnel and block it, causing an inaccurate reading.It must not be positioned in a sheltered area – being positioned in a sheltered location (such us beside your house or a fence) co uld significantly increase or decrease the amount of rain depending on the wind direction, and cause an inaccurate reading. The gauge should be positioned at least twice as far away from the object as the object’s height (e.g. if the fence is 6 feet high, the gauge should be positioned at least 12 feet away). Your weather equipment must not be located near any magnetic, steel, or iron objects – magnetic, steel, or iron objects can affect the amount of time the magnet will hold the bucket or whether it will hold it all, causing an inaccurate reading. Will a Rain Gauge Measure Snow? If it snows where you live, most rain gauges will not be able to measure the snow fall; snow will block the opening of the collection funnel. However, special snow gauges are available to measure this. Following these recommendations should ensure your get an accurate result from your tipping bucket rain gauge.