Rain Gauge: Measuring Rainfall Totals
The Rain Gauge, also called Udometer or Pluviometer, is an essential measuring sensor in your personal weather station. The rain gauge is used to measure and record the precipitation (rainfall) over a period of time. Technology has brought the rain gauge from manual to automated recording, but the process has stayed the same since it's invention. We will cover the most common types of rain gauges.
Graduated Cylinder Rain Gauge
Also called the measuring cylinder is the most manual of the rain gauges. Basically a funnel attached to a tall cylinder with measured markings, usually in milliliters, that collects falling rain and is measured visually. The graduated cylinder rain gauge is inaccurate in measuring intense rain and is susceptible to freezing temperatures clogging the funnel.
Weighing Rain Gauge
This gauge uses a collector cylinder to collect rainfall of all types including rain, hail and snow. The weighing rain gauge is good to accurately measure precipitation and rainfall intensity. One method is using a scale to weight the rainfall which also connected to a pen arm. The pen arm rises equivalent to the intensity of the rainfall. This combination gives and accurate reading of rainfall and intensity. Weighing rain gauges are used mostly in professional and agricultural settings.
Tipping Bucket Rain Gauge
This gauge uses a cylinder collector with two equally balanced cups. As one cup fills with precipitation it dumps into the cylinder and brings the secondary cup up to start collecting, also marking one "click". The cups or buckets collect and mark 0.2mm at a time. Rainfall intensity is measured by the number of "clicks" within a set amount of time. The only downfall is a possible inaccuracy of +- 0.2mm if the amount of rainfall collected during one rainfall doesn't tip the cup or bucket, thus being measured on the following rainfall. This is negligible for personal weather stations, for which the tipping bucket is most used.
There are accessories you can purchase to help accurately measure precipitation amounts. You could add a wind sheild which is designed to stabilize the air above the collector funnel to allow the rainfall to fall more vertically. Another accessory which is pretty much a necessity for those of us in the North of the US and Canada is the rain gauge heater. The rain gauge heater is a thermostatically controlled heating element to keep the collector from freezing.
Rain gauges should ultimately be mounted in a non obstructed area to allow accurate readings. Rain gauges can be bought as separate sensors with LCD display and/or remote console but are most commonly packaged with a personal weather station for home use. If you don't have one, add a rain gauge to your weather station configuration today.
