Which instrument is used specifically to measure precipitation?

The rain gauge is the correct instrument used specifically to measure precipitation. It is designed to collect and quantify the amount of liquid precipitation that falls over a given period. This instrument typically consists of a cylindrical container with a funnel that directs rainwater into a measuring tube, allowing observers to determine the amount of rainfall in millimeters or inches.

In meteorology, accurate measurement of precipitation is crucial for a variety of applications, including weather forecasting, hydrology, and agriculture. Rain gauges can be used in both professional meteorological stations and by individuals for personal weather monitoring.

The other instruments mentioned serve different purposes: an anemometer measures wind speed, a hygrometer measures humidity, and a barometer measures atmospheric pressure. Each of these instruments plays a significant role in weather observation, but none are specifically designed to measure precipitation like a rain gauge.