Rainfall is a climatic condition when the amount of water falls as rain or snow over a specific location. Snowfall is one type of rainfall. According to the climate, time, and region the definition changes. When the atmospheric water vapor condenses into liquid water, it forms rain. Rain and rainfall both are important factors in the water cycle as the cycle deposits the the freshwater to the earth.
In this article, we are going to discuss the types of rainfall in detail.
Types of Rainfall| Class 11 Geography Notes
Types of Rainfall
As per the major characteristics, we can classify the rainfall into three different types Convectional rainfall, Orographic or relief rainfall, and Cyclonic or frontal rainfall as mentioned below.
Convectional Rainfall
Convectional Rainfall occurs when the ground and the above air become warm due to sunlight. Gradually, the warm air rises and cools down. After this process, it forms clouds. If sufficient condensation occurs, the Convectional Rainfall starts.
Here are some major characteristics of the Convectional Rainfall as mentioned below:
- Convectional rainfall forms due to the convention of the currents.
- This type of rainfall occurs due to the moist atmosphere.
- When the temperature becomes so high, the warm air starts to rise. This process is known as the evaporation.
- After reaching a certain height, the warm air starts to cool down. After cooling down it expands gradually which leads to cumulus cloud formation.
- The intensity of this type of rain is unstable at its initial stage.
- Lightning and thunderstorms are very common due to the heavy rainfall.
Orographic or Relief Rainfall
Orographic or Relief Rainfall occurs when moist air rises over to the mountains or hills due to some force. After reaching a certain level. it cools down and condenses. After this process, it forms the cloud and rainfall happens.
Here are some major charcteristics of the Orographic or Relief Rainfall as mentioned below.
- Orographic or Relief Rainfall happens when moist air is lifted near the mountain.
- Orographic clouds are the reason for this type of rainfall.
- This type of rainfall happens with the wind mostly in the mountain areas.
- It is rapid for that this type of rainfall is uncontrollable.
Cyclonic or Frontal Rainfall
Cyclonic or Frontal Rainfall is a specific type of rainfall that happens when the warm moist air meets with the cold and dry air suddenly.
Here are some major charcteristics of the Cyclonic or Frontal Rainfall as mentioned below.
- Cyclonic or Frontal Rainfall majorly happens due to different cyclonic activities.
- It moves in a clock motion and it changes as per the hemisphere.
- Clockwise Cyclonic or Frontal Rainfall mostly happens in the southern hemisphere.
- Anti Clockwise Cyclonic or Frontal Rainfall mostly happens in the northern hemisphere.
World Distribution of Rainfall
Rainfall distribution varies across the Earth’s surface, with coastal areas generally receiving more rainfall than interior regions. As one moves away from the equator towards the poles, rainfall typically decreases steadily. The oceans receive more rainfall than landmasses due to their vast water bodies.
Between 35° and 40° latitude north and south of the equator, heavier rainfall occurs on the eastern coasts, decreasing towards the west. However, between 45° and 65° latitude north and south of the equator, rainfall is influenced by the westerlies, resulting in heavier precipitation on the western margins of continents, decreasing towards the east. Areas where mountains run parallel to the coast experience greater rainfall on the windward side, decreasing towards the leeward side.
Major precipitation regimes are categorized based on annual precipitation levels. The equatorial belt, windward slopes of mountains along western coasts in the cool temperate zone, and coastal areas of monsoon regions receive heavy rainfall exceeding 200 cm annually. Interior continental areas receive moderate rainfall ranging from 100 to 200 cm annually. Coastal areas of continents receive moderate amounts of rainfall. Tropical land interiors and eastern/interior parts of temperate lands receive rainfall between 50 and 100 cm annually. Regions in the rain shadow zone of interior continents and high latitudes receive very low rainfall, less than 50 cm annually.
The seasonal distribution of rainfall also varies, with some regions experiencing even rainfall throughout the year, such as the equatorial belt and western parts of cool temperate regions.
Types of Rainfall Based on Intensity
Based on the intensity, there are three types of rainfall as mentioned below.
| Rain Intensity | Rate of Rain (millimeters) |
|---|---|
| Light rain | 0 to 2.5 |
| Moderate rain | 2.6 to 7.6 |
| Heavy rain | Beyond 7.6 |
Significance of Rainfall
Here are the significance of Rainfall as mentioned below.
- Rainfall is much more important for the plants and animals to stay alive.
- Rainfall brings the fresh water to Earth by sustaining the water cycle.
- Most of the world’s freshwater comes to the Earth from rainfall.
- We can have water shortages due to a lack of the sufficient of rainfall and major disasters like droughts.
- It helps us to create the different habitats.
- Rainfall gives us the water for farming and with the reserve rainwater we can make the sufficient electricity.
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FAQs on Class 11 Types of Rainfall
What are the types of rainfall class 11?
The types of rainfall based on intensity can be classified as: Light rain – Rate of rain varies between 0 to 2.5 millimetres. Moderate rain – Rate of rain varies between 2.6 millimetres to 7.6 millimetres. Heavy rain – Rate of rain is beyond 7.6 millimetres.
What is convectional rain Class 11 geography?
Convectional rainfall refers to the precipitation that results from the upward movement of warm, moist air in the atmosphere. The process begins with the heating of the Earth’s surface by the sun, causing the air above it to warm up. As the air warms, it becomes lighter and starts to rise.
How does rainfall occurs class 11?
The clouds continue to rise upwards, it gets cooler, and more droplets are formed. As they get heavier, they become more difficult to remain in the air and cause rain. The falling of water from the sky in various forms is known as precipitation.
What is orographic rainfall Class 11?
Orographic rainfall also called orographic precipitation or snow. Orographic rainfall is precipitation produced when the mountains of uplands act as barriers to airflow, forcing the air to rise and the moist air moving upslope coo down by producing clouds and precipitation.
What is the main type of rainfall?
Three main types of rainfall are convectional rainfall, cyclonic rainfall and orographic rainfall.