Rain Gauge Facts

Rain Gauge Facts
A rain gauge is a tool used by hydrologists and meteorologists to measure the amount of rain over a particular period of time. Rainfall is known to have been recorded as far back as 400 B.C. in India and 500 B.C. in Ancient Greece. The rain accumulation then was used as a method to determine crop growth and therefore taxes on land. The first standardized rain gauge was invented in 1441 in Korea. In 1662 the first tipping bucket rain gauge was invented in Britain by Christopher Wren and Robert Hooke. The first systematic rainfall measurements were done between 1677 and 1694 by Richard Townley in Britain. Rain gauges are considered by many to be some of the oldest weather tools used in history.
Interesting Rain Gauge Facts:
A rain gauge is essentially a cylinder that catches rain and measures the amount of accumulation via a scale.
A tipping bucket rain gauge is the modern and common rain gauge. It does not actually tip. Funnels collect rain alternately and when one fills it tips and allows the rain to spill out. It records the rainfall in increments of .01 inch (or equivalent in other measurement unit) by sending a signal to record that the funnel was tipped to measure rain accumulation.
Rainfall in the rain gauge is measured over a unit area. A millimeter of rain measured in a rain gauge would equal one liter of rain in a meter squared.
Other names for rain gauges include udometers and pluviometers however these are the scientific names and most people simply refer to them as rain gauges.
Rain gauges are not effective in some weather conditions such as in a hurricane when the wind affects the ability of rain to accumulate in the rain gauge's tubes.
If the temperature drops to freezing this can affect the accuracy of a non-heated rain gauge because the rain can freeze on the edges of the gauge and result in lower recorded rain accumulation.
The main types of rain gauges are the optical rain gauge, tipping bucket style rain gauge, weight based rain gauges, acoustic rain gauges, and the graduated cylinder rain gauge.
The National Weather Service's standard rain gauge is made up of a funnel that empties into a graduated cylinder fitted within a larger container for overflow.
The weight based rain gauge is made up of a storage bin that must be weighed to obtain the mass of the rain accumulation. This type is more expensive but it can measure other precipitation forms other than rain including snow and hail.
Weight based rain gauges can also be used to measure chemicals in the atmosphere, such as the All Weather Precipitation Accumulation Gauge.
The optical rain gauge is made up of a row of funnels that collect rain, a photo transistor detector, and laser diode. The laser diode senses drops of water and the photo detector records or transmits the flashes of the laser to measure rainfall.
An acoustic rain gauge senses rain sounds and estimates the amount of rain by the sound rain drops make based on their size.

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