You’re not alone if you’ve ever wondered how to read a rain gauge. The device is available in a variety of forms and functions. Some measure instantaneous rainfall, while others record total rain. Others use mechanical principles to calculate total rainfall. In general, though, rain gauges provide accurate rainfall information. However, some rain gauges are better than others for estimating rainfall, and the type you purchase should depend on your specific needs.
Location of a rain gauge
The Brue catchment is in the South West of England and is home to 49 Casella tipping bucket rain gauges covering a drainage area of 135 km2. The Brue catchment was chosen because of the quality of the data available and the characteristics of rural UK catchments. In addition, this research has provided new insights into the use of rain gauges and weather stations. To learn more, visit the project website.
The ideal location for a rain gauge is at least 30 cm above the ground. The higher the gauge is, the minor catch it will have from nearby objects. Make sure that the gauge is not mounted on a post, which will cause it to be covered by branches or foliage. Ideally, the post should extend more than 20 inches above the ground. It is also best to place the rain gauge in a grove with no trees that are too tall or too low to obscure the reading. Visit https://instrumentchoice.com.au/instrument-choice/weather-stations/rain-gauges for more information.
Types of rain gauges
The main difference between the tipping bucket type and the traditional type is the collection mechanism. The former focuses on recording the range of humidity versus time, while the latter measures the mass of rainfall. The tipping bucket style has two separate compartments and is balanced in a delicate balance on a horizontal axis. Each compartment has a funnel and a sharp edge receiver, and the latter is often used as a recording rain gauge.
Weighing rain gauges rely on a sensor that requires continuous electrical energy to work. The other two types do not require electricity, but a reliable power source is required for autonomous operation. It makes weighing rain gauges less suitable for agricultural and IoT applications. In addition, they require frequent manual intervention and maintenance. In contrast, siphoning rain gauges can automatically measure rainfall based on the amount of water in the cylinder.
Limitations of a rain gauge
Despite their popularity, rain gauge does have some limitations. They are only accurate to a small extent, and they can be prone to error, especially during storms and hurricanes. Also, they are unreliable in situations where the wind speed is extreme. In addition, rainfall gauges only measure localised amounts of rainfall. The official Seattle weather station, for example, has a rain gauge that was placed by chance at the airport. However, the actual annual rainfall in Seattle is around ten inches higher than the city’s official records. In addition, rain gauge readings are often taken by automatic weather stations and volunteer observers and are reported to the Weather Bureau.
Another issue is the faulty reed switch. When the rain gauge isn’t mounted correctly, it can lead to a random wind count of 0.01 inches. It may also not be mounted securely. Wind will also cause a weather station to move and wiggle, which will produce occasional wind counts. It is why a rain gauge needs to be securely mounted. Nevertheless, even if it’s appropriately mounted, some factors can still affect the accuracy of the data it produces.
How to read a rain gauge
A rain gauge, also known as an udometer or pluvia metior, is used by hydrologists and meteorologists to measure rainfall. It measures the amount of liquid precipitation, typically measured in millimetres, over a specific period. There are two types of rain gauges: manual and automatic. Regardless of the type of rain gauge you have, it is essential to know how to read it.
A rain gauge consists of a graduated sheet of cardboard connected to a mechanical device. Each time the sheet tips, the rainwater increases, and the gauge translates that information into a graph. The y-axis indicates how high the rainwater fell. If it falls to the ground, the meter will reach zero, indicating that no more rain is expected. Once the sheet has reached zero, it will be empty again.