Rainfall is the fall of rain. The amount of rainfall is the amount of water that falls within a specific area in a specific period. It is essential to know why rainfall is so significant for humankind to understand the types. Rainfall is an important phenomenon. Many tangible and intangible needs are vital for the survival of humans, such as the generation of electricity, the irrigation of crops, etc.
Why Should We Know About Rainfall?
Rainfall is important not only as a raw material to humans but as a vital source of fresh water, without which humans cannot survive. As 70 percent of the human body is made up of water. Plants also greatly benefit from rainfall as they need that water to photosynthesize and grow from seedlings into mature plants.
In addition, rainfall is specifically important to forest plants with no alternative artificial water source. The only way to survive is to absorb water from the soil through their roots. Hence rainfall is significant to them to stay. Rainfall influences the Earth’s weather system and influences the movement of the oceans to produce moving currents rapidly.
It is a result of the water cycle which includes the evaporation of water from lakes, rivers, ponds or any major water body and the condensation of this accumulated water vapor in the form of rainfall to the Earth’s surface. Even though the rain has huge importance in our lives, it can also lead to a big disaster. Rain has made some irreplaceable losses on a large scale in the past.
To avoid this kind of tragedy, scientists had started predicting the rain before it began. To accurately guess the next rainy day, it is important to identify the reasons for rainfall.
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Types of Rainfalls
Knowing when the next rainfall will happen to extract full advantages is essential. For this, scientists have been studying the patterns and types of rainfalls.
There are three main types of rainfall;
The geographical position of the land and its climate influence determine which type of rainfall can be experienced in the area. Some areas of the world experience all three, while some experience rarely any.
1. Orographic or Relief Rainfall
Relief rainfall can frequently be observed in the areas located on a mountain or near a large water body, for example, the sea or the lake. This rainfall phenomenon is simple and can be explained with the basic scientific process.
When Does It Occur?
As the sun shines brightly on the water body, the temperature of the water body increases, and some of the water molecules break free from the body. This is called evaporation. The evaporated water is dense and in the form of vapors. Hot air is much lighter than cold air.
This can be observed in homes that have been built in ancient times. These homes had high roofs. The hot air would rise to the top, and the lower sitting area would become cooler. This helped to keep the temperature of the living spaces in check. Similarly, the hot water vapors rise to the clouds.
The inward-push these vapors towards the mountainous regions. At this height, the mountain has very low temperatures, and hence the hot vapor cools down. As it cools, the density increases. This causes the gas molecules to transform into liquid, creating a cloud.
Now, this process of hot gas turning into liquid is called condensation. Condensation is a daily process observed when driving in cold weather with a heater turned on inside the vehicle.
If you notice, tiny water droplets began to form on the glass. This happens due to the same process. The clouds are then carried away by the wind. It blows them to an area farther from the region.
That dense cloud becomes even denser and turns into liquid. This then falls as rain. Therefore, relief rainfall takes the water from the water bodies and returns them to the land.
Due to hot water vapor, humidity increases that causes discomfort to humans. When it rains, a drop in temperature occurs, which relieves us from humidity. Hence, it got the name, Relief rainfall.
Where does it occur?
Due to the specific process, this kind of rainfall happens mainly in the hilly areas. It needs the difference of temperature to be implemented. These areas are Hawaii, the Sierra Nevada, and the Andes.
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2. Convectional Rain
The rainfall, which occurs mainly on a hot day and brings a grey sky, dark clouds (cumulonimbus) and heavy, thundery showers, is called convectional rainfall. The concept behind this rainfall is a bit similar to the relief rain. This type of rain is also caused by the differences in hot and cold air properties. It is caused on very hot days when the scorching rays of the Sun heat the Earth’s surface.
When Does It Occur?
When the ground gets heated up, it causes the air near it becomes hot. This hot air near the ground rises because of its low density compared to the air above. The cold air is heavier, so it settles down and makes way for the hotter one to rise. As this hot air rises in altitude, it cools and eventually condenses, resulting in a cloud formation.
When this cloud begins to saturate from the accumulation of water vapor, it precipitates in the form of heavy showers. This kind of rain sets up convectional currents. This means that as the hot air rises, it cools down, and the air beneath it heats up. Now, the other air will rise, and it will continue until the Sun loses the intensity to heat the Earth enough to transfer it to the air above.
Where Does It Occur?
This type of rainfall is very common in tropical areas such as South East England during warm sunny spells. It is because this needs extremely high temperatures to be implemented. Any area that has a high-temperature continuum will experience this type of rainfall. It may not need a big water body around. This type of rainfall is also common among dense forests and large plains or plateaus.
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3. Cyclonic /Frontal Rain
This type of rain occurs in the ocean or sea faces. They are named differently in different regions. Cyclones in the Middle and Western East, Typhoons in the East and Tornados in the West. This kind of rain happens when a difference in pressure and temperature takes place between big areas over the oceans.
When Does It Occur?
In this rain again, hot and cold air properties play an essential role. Frontal rain occurs when cold air from the North and South poles comes in contact with the warm air from the tropical areas.
The warm, tropical air rises over the cold, polar one because of its low density and is cooled as it rises into the atmosphere. This cooled and condensed tropical air forms a stratus cloud that precipitates rainfall when saturated with water vapor.
Where Does It Occur?
It is very common in the UK, Great Britain and Ireland. The location of these countries is such that they make the perfect point for the two breaths of air to intersect. Many coastal areas such as Indonesia, Japan, India etc., face cyclonic rainfall. They are also followed by high altitude waveforms that hit the coastal areas and impact the livings.
Rainfall is important in so many ways. Keeping track of the amount of rainfall happening in the areas is very important. It helps plan the crops, electricity generation, and other important aspects of living. Knowing the rain pattern helps predict the countries’ productivity and GDP. Hence, understanding the types of rain becomes essential as one can plan and forecast rain by studying variables.