A rain gauge (RAIN) gathers and measures the amount of liquid precipitation over a set period of time. ARM uses many types of rain gauges at its climate research facilities.
The tipping bucket rain gauge consists of a funnel that collects and directs precipitation into a seesaw container that tips after a pre-set amount of liquid enters. When the seesaw tips, it sends an electrical signal that is counted by a recording device.
The weighing precipitation gauge consists of a storage container, which is weighted to record the mass of precipitation. Some models measure the mass of precipitation using a pen on a rotating drum or by using a vibrating wire attached to a data logger. The advantage of this type of rain gauge is that it can measure all forms of precipitation.
Disdrometers are used with rain gauges to add details about the precipitation being gathered. They are capable of measuring the velocity and size distribution of precipitation, measurements important for studying the evolution of water droplets.