What Are Rain Gauges Used For?
Society has recorded and measured rainfall for at least 500 years, but it is likely this practice goes back much further. Rain gauges are a simplistic and relatively accurate tool to measure the amount of rainfall in an area for professional and amateur meteorologists alike. The data from rain gauges are especially important for farming and planning travel.
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History
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It is uncertain who first measured precipitation. It is likely that early civilizations such as the Mayans and Greeks measured rainfall, but no record of this exists. According to CoCoRaHS, a volunteer network that measures rain across the United States, Korean King Sejong made the first recorded attempt to measure rainfall sometime between 1397 and 1450.
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Function
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An official rain gauge used by meteorological professionals consists of a large cylinder holding a funnel exactly one-tenth the size of the cylinder, with a smaller tube at the end containing a measuring stick or readings on the side. Each inch in the funnel counts as one-tenth of an inch of rain. A rain gauge uses the smaller tube to measure rain rather than the entire cylinder because the smaller tube exaggerates the height of precipitation of the collected precipitation. It is hard to get an exact reading when dealing with depths as small as a tenth of an inch, thus the need to expand the size of the field of view.
Meteorology
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The main function of the rain gauge today is to gather data about precipitation for weather predictions, according to Colby College. Meteorologists need precise measurements for short- and long-term patterns in the Earth's climate. Although most weather forecasting today takes place on computers that model the atmosphere mathematically, satellites and computers still need observational input from tools such as a gauge, according to Encyclopedia Britannica.
Agriculture
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The rain gauge was invented to help farmers make decisions about crop planting. Hundreds of years later, this is still true for much of the farming world, according to Farm Radio International. Despite the advances in electronic communication and weather technology, these devices have not reached all parts of the world, especially the developing world. Third world farmers still use a basic rain gauge and note-taking to predict dry weather or potential flooding.
Considerations
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Although the rain gauge method for measuring rainfall offers much greater accuracy than simply catching water in a cup, a gauge is still prone to some errors, according to the book "Fundamentals of Hydrology." Rain gauges need to be checked immediately after rainfall; otherwise, evaporation could mean a lower reading. A perfect rain gauge is flush with the ground, but this could cause splash-back from the ground nearby and give a higher-than-normal reading. However, raising the gauge above ground presents another problem: turbulence. Greater wind speeds create more turbulence around the gauge and can cause a measurement error of up to 20 percent.
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