Meteorologists people who study weather and researchers have developed numerous measurement devices that enable them to study the extreme variability of rainfall. We will explain the functioning of the three most commonly used devices. The most common rainfall measurement is the total rainfall depth during a given period, expressed in millimeters mm. For instance, we might want to know how many millimeters of rain fell over the course of 1 h, 1 day, 1 month, or 1 year.
You can easily get a rough measurement of rainfall depth at home. Just follow these steps: 1 Take a bottle with smooth sides, cut off the upper part and turn it upside down on the top of the bottle, to create a sort of funnel see Figure 1A. The bumps would otherwise affect the measurement.
If you plan to take your measurements during the summer, some of the water inside the bottle will evaporate up to few mm a day and this will affect your measurements. To avoid this, you can add a thin layer of oil to the water.
Since it is lighter than water, the oil will float on the top of the water and prevent evaporation. The measurements you get from your rain gauge will tell you how much rainfall occurred over a certain period of time. Professionals use more complicated devices called tipping bucket rain gauges and you can see one in Figure 1B. This rain gauge looks like your homemade device, except that there are two buckets beneath the funnel.
The water falling into the rain gauge will be routed to one bucket by the funnel. Once that bucket is filled, usually after 0. The process starts all over again with this other bucket, until it is filled and tips. The rain gauge records the time of all the bucket tips, which will give the researcher data about how quickly the rain falls over time. Figure 1C shows an example of the data that can be obtained using a tipping bucket rain gauge. These observations were made on 27 June The rainfall depth in mm quickly increased between and , meaning that it rained a lot during that period.
During a period of light rain, this device is not very precise. For example, between and , all you can tell is that 0. If there is a lot of wind, that can also affect the accuracy of the device.
What is rainfall made of? Rain drops, obviously! Rain gauges are not sensitive enough to be able to take measurements of individual rain drops. To start collecting data about drops and their size, you need a device called a disdrometer. Follow these steps: 1 Take a plate and put a few millimeters of flour all over it. You will observe something similar to what is shown in Figure 2A , and you will notice that drops do not all have the same size—some are very small and some are very large!
Actually, the craters are bigger than the drops because the water slightly spreads after it hits the plate, but they still enable you to directly visualize the great variety of drop sizes, even during a very short time. As you can imagine, meteorologists and researchers wanted a device more automatic and precise than the flour plate! They now mainly use optical disdrometers, which function as shown in Figure 2B. This kind of disdrometer is made of two parts: a transmitter and a receiver.
The transmitter generates a sheet of light a few mm in height. The receiver is aligned with the transmitter, meaning that when it does not rain, the receiver receives all of the light. Oil Boiler Outdoor Security Camera. Ultrasound Underfloor heating. Video Surveillance Visiophone Voice Assistant. Rain Gauge A rain gauge is an instrument used in meteorology to measure the amount of rainfall during a given period. Used by the Greeks as early as BC to measure precipitation, this device that was once only used by professionals now has its place in the home.
Weather amateurs love using it to fine-tune their observations, while gardeners can use it to plan their gardening activities and watering. How does a rain gauge work? The purpose of a rain gauge is to provide a measurement of the quantity by volume or mass of precipitation - i.
This quantity is expressed either in millimetres or relative to the surface area, in litres per m 2. Rain gauges traditionally take the form of a funnel, also called a collecting device, which is used to collect rainwater during precipitation and direct it either into a kind of graduated cylinder that needs to be manually emptied afterwards in the case of the most basic models, or into a more elaborate tipping bucket system that measures the water that falls before draining it.
The bucket system enables continuous measurement without the user having to empty the water between every reading and prevents measurement errors caused by evaporation. These days, most rain gauges feature electronic sensors that save the device's data and remotely send it to a weather station. To obtain reliable measurements on the level of ground precipitation, it's best to place a rain gauge on a flat surface in an open area where all of the water falling from the sky can be collected by the collecting device.
It's usually recommended to place the instrument between 50 cm and 2 m off the ground. This makes it easy to install and to read the measurements in the case of a graduated cylinder. Placing the instrument too high up or on a sloping surface could cause reading errors. It's also necessary to be aware of errors caused by the presence of an obstacle nearby the collector: if it's windy, the rate could appear to be lower and the volume collected could be less than the average on the ground.
Discover all our products What type of rain gauge should you choose? There are many different types of rain gauge , all of which work differently and have different levels of accuracy. You should first choose a rain gauge based on its capture method, either manual or electronic.
The first type means you need to regularly empty the recipient, which might be a problem if there's heavy rain or snow, or alternatively if hot weather makes evaporation more likely. Stagnation can also cause a problem in terms of the accuracy of the height observed. By saying the inches as metric units for rainfall measurement, we try to interpret the inches in the storm or the inches in the last 24 hours observed in the rainfall.
Or, more specifically, with the inches, you can say how many inches are observed in some particular period. But, what is 1 inch of rain? Is it something new or different? You can understand 1 inch of rain as it is much more in 15 minutes than the 1 inch of rain observed in the last month. Do you know that 1 inch of rain is so powerful that it can even cover the entire ground if it doesn't assimilate with other water bodies like lakes or rivers and stays in a single place?
Isn't it amazing!! If we see in figures, then 1 inch of rain can be described as a value equivalent to 4. You must be wondering that how the rainfall is measured in inches? Well, that is simple. You have to check the measurement scale in the cylindrical glass concerning the water level. The main rain gauges come with a wide funnel that ultimately takes the rainwater to the cylindrical opening, which is calibrated as one-tenth of an inch of rain.
This calibration plays a vital role in measuring one inch very easily when the rainwater is collected inside the gauge. With the help of inches calibration, it becomes very easy to read even highly precise values. Rain Gauges fundamentally measure the rain precipitation, and there are several types of rain gauges, each one performing differently.
Yet one thing can be assured that from all the methods, you will get a near accurate intel on the amount of rainfall in your area. Although there are several kinds of rain gauges in general, some of them indigenous mechanisms which occur only in certain specific regions, there are three broad types of rain gauges.
They are:. Each type of gauge performs its primary function of rainfall recording and a few distinctive functions. Let us discuss this in detail. Meteorologists are the experts who can measure the rainfall levels with utmost accuracy and precision levels.
But, you must be wondering that how they can measure the rainfall? Is there anything special that they possess? Need not worry as we will address your concern, and you can easily know how they measure the rain. The most basic concept used for measuring rainfall levels is to find the rainfall depth during a specified period.
But the professionals opt for complicated devices like tip bucket rain gauges that they employ to measure the rainfall. This instrument consists of two buckets placed beneath the funnel. When the rainfall starts, then by crossing the passage of the funnel, the first bucket starts filling, and it usually gets filled after 0.
Once this bucket is filled, the tip shifts to another bucket, and this process repeats recursively. The rain gauge keeps a tab of the tips during the rainfall to maintain a proper record. This data helps to find the meteorologist that how quickly does the rainfall is for a specific time.
So, this is how the professionals measure the rainfall levels. Measuring rainfall has become essential for the follow-up proceedings, such as determining the climatic conditions of a region and weather forecasts.
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