Can you imagine life without water?
Yet, many individuals don’t know the primary source of fresh water.
Surprised? Don’t be.
Honestly, most of Earth’s activities depend on fresh water, especially rain; whether economically, socially, or even politically.
Related: Why should we save clean water?
For example, a farmer to plant crops would have to look to the sky, hoping for a downpour, before getting set to the farming activities. Their livestock would emaciate if drought hits. But at the same time, when harvesting the produce, he wishes rain should not have existed in the first place!
On the other hand, a politician would do anything he can to ensure there is no rain to carry out the rally successively. How would you celebrate your holiday on a rainy day? (Sleeping!) One man’s food is another man’s poison, they say. So is rain.
Rain plays a crucial role in human activity on this blue planet Earth. To utilize its benefits, we have to measure the amount to determine and predict the future actions we would take. One way of measuring this amount of rain is by using a proper rain gauge. Make sure to get the right instrument that fits your need.
In this article, we will explain how to measure the rain with different rain gauges.
Types of rain gauges
Any device that can measure the amount of rain is referred to as a rain gauge, also called pluviometry. This is one of the oldest tools in the meteorological department. You need to know how to properly use such a device before deciding to purchase any model.
Please note that the different types of rain gauges you will find on the market have some common functionality. However, each model is suitable for a specific use. For example, if you work in gardening or are just an enthusiast, the manual rain gauge is for you. On the other hand, if you are a professional or work in the agriculture or meteorology sector, the rain gauge with direct or automatic reading is more appropriate.
There are two main types of rain gauges:
- Non-recording rain gauges
- Recording rain gauges
The recording rain gauge has to be calibrated before using so that it can record the amount of rain accurately. Whereas, the non-recording rain gauges generally collect the rain but do not record the exact amount.
The following are the types of recording rain gauges:
- Measuring cylinder rain gauge
- Tipping bucket rain gauge
- Weighing bucket rain gauge
- Floating rain gauge
- Optical rain gauge
- Ultrasonic rain gauge
How to use the rain gauge
The use of a rain gauge must follow some definite rules. However, it is also essential to know its principle.
For a conventional rain gauge, during downpours, it collects the water in a kind of reservoir. As the quantity increases, a float rises, and a stylus transcribes the water’s rise in a diagram. When the tank is full, it is emptied through a pipe called a siphon. The collected rainwater will then pass into a container. Once the rain gauge is empty, the stylus is reset to zero, and then it will describe a straight line in height. The same scenario repeats if there is another downpour.
In some other models, water is collected at the top of the meter and then stored in the tube. There is also a cover preventing the evaporation of water. The precipitation measurement can then be interpreted through graduations.
It’s still important to point out that errors may occur like all instruments used to measure meteorological data. Usually, these are less and have no severe impact on the overall interpretation. In the majority of cases, however, certain rules must be taken very seriously. Sometimes the mistakes are the result of design flaws. The most common falsified data remain the consequence of improper installation and use. The environment is also a factor that should not be taken lightly.
Regarding the actual use, you must know how to interpret the measurements. Also, you will need to know the best conditions to avoid erroneous data.
How to measure the rain with the rain gauge
Is there a standard way of measuring the amount of rain using rain gauges?
No. The method of measuring rain varies from one gauge to another. It is, therefore, necessary to determine the technique of measurement for each rain gauge.
1. Measuring rain with a non-recording rain gauge
An example of a non-recording rain gauge is the Symons Rain Gauge which gives only the total amount of rainfall within a given period.
It has a cylindrical metal bottle receiver and a funnel. The receiver’s diameter and funnel’s top diameter are equal and approximately 127mm. The funnel fits in the receiver neck, and the entire construction placed metal casing that has suitable packs. For stability, the casing’s base is wider, about 210mm. A calibrated measuring jar is provided to this gauge to measure the amount of rainfall at the end of the period.
It should be noted that the funnel acts as a collector of the raindrops before they reach the ground and is always raised to prevent splashes. The graduated is the measuring instrument here and not the gauge itself. Measurements are normally taken 0830hrs daily.
2. Measuring cylinder rain gauge
This is the simplest recording rain gauge. It consists of a large graduated measuring cylinder and a funnel. The funnel is placed above the measuring cylinder to tap or collect raindrops. As the water fills the jar, it can be measured directly.
Note that this gauge’s cylinder does not serve the same purpose as that in a non-measuring cylinder. Here you have to read the data directly without emptying water from the cylinder.
3. Measuring rain with tipping bucket rain gauge
This gauge has a funnel put in the cylinder and then put in a pair of buckets that are balanced horizontally. Technically, a funnel will collect rainwater, directed to a cylinder that drains to a bucket. When the bucket feels water to a certain level, say 0.03cm, it will simply tip, bringing the next bucket into position. This process sends a signal to the computer, which counts the number of tips to determine the amount of water collected.
4. Measuring with weighing bucket rain gauge
This rain gauge has a cylinder placed on an electronic scale. Water entering the cylinder increases the weight that provides indirect rainfall measure. These scales can be connected to charts tracing the amount of rainfall over time.
5. Floating rain gauge
This gauge has a funnel leading to a floating chamber. The float rises as the water accumulates the funnel. The float rises with a pen that traces and records rainfall to a rotating drum. The pen operates on the lever system.
6. Optical rain gauge
There are also digital rain gauges, such as optical rain gauges, which use laser and optical detectors. There is a reduction in the amount of light as drops of rainfall through the laser-optical detector gap. This light intensity difference is perceived as the amount of rain.
The different types of rain gauges available will help you achieve your goal, depending on the efficiency, availability, and speed. Though the result might be the same, the mode of operation is different.
Let us know if you need more information about the functionality of different rain gauges. Or, if you’ve used one recently, share your experience with us in the comment section below.
Featured image courtesy Holman Industries