Monsoon will reach Keralam on June 4.
North India is scorching with heat. The temperature is reaching 48-50 degrees. Monsoon will reach Keralam on June 4. Monsoon brings rain and provides relief from the heat. But the interesting thing is that most people in India think that there is only one type of monsoon, but no. There are two types of it. Monsoon is not just a one day rain. This is the seasonal change in wind direction. With this change, moist winds come towards India. Then it rains in different parts for several weeks.
Let us understand with this excuse that how many types of monsoons are there in India? How do they create pressure for rain? Why does monsoon come first in Kerala?
Why does monsoon come first in Kerala?
This question is very common. The main reasons behind this are sea, wind direction, and geography.
- Kerala is right on the shores of the Arabian Sea. The Arabian Sea branch first hits the western coast of India. Kerala is the first big gate on that path.
- More moisture is available quickly from the Arabian Sea. During summer the wind from the Arabian Sea can pick up a lot of moisture. When the same wind reaches the Kerala coast, the atmosphere quickly becomes humid, and the onset of rain becomes easier.
- Western Ghats give immediate rise: Just behind Kerala are the Western Ghats. The coastal wind hits the mountains and rises up. Clouds form as the altitude rises, and orographic i.e. mountain rain intensifies.
- The main flow of monsoon first sets in South India. The monsoon flow gradually strengthens. In the initial phase it organizes first in the southern parts. Then it spreads towards the north.
Picture of Kochi, Kerala.
How many types of monsoons are there in India?
Mainly two types of monsoons are considered in India.
- South-West Monsoon: It remains active between June and September. This is called the main rainy season of India. A major part of the total rainfall occurs during this time. it Divides into two main branches and moves forward. First, Arabian Sea Branch. It first moves towards Kerala and Karnataka coast. Collision with the Western Ghats can cause heavy rain. Second, the Bay of Bengal branch. It goes towards North-East India and Bengal-Orissa. Then spreading in the plains, it moves towards north and west.
- North-East or Returning Monsoon:It falls between October and December. It is also called retreating monsoon. It gives good rain especially over Tamil Nadu, South Andhra, Puducherry and surrounding coasts.
The real reason for monsoon is the difference in air pressure and temperature. Photo: Pexels
How does monsoon create pressure?
Clouds are not the main cause of rain. The real reason is the big difference in air pressure and temperature.
- The ground heats up quickly in summer:The land of India becomes very hot in April-May. Especially in North-West India, Thar region, and Ganga plains. Hot air is light. Light air rises up.
- Less pressure is created on the ground:When air rises, the pressure near the ground decreases. This is called low pressure. At the peak of summer, a large low pressure area may form over North India.
- The sea remains relatively cool, the pressure there is high:The sea heats up slowly, so even in summer the temperature of the sea does not increase as much as that of the land. Relatively high pressure may persist over the sea.
- Air always moves from high pressure to low pressure: This is the key to monsoon. The air moves from the high pressure sea area towards the low pressure Indian land area. These winds pick up moisture from the sea.
- The wind turns while crossing the equator: The winds coming from the Southern Hemisphere cross the equator. Winds do not blow straight due to the rotation of the Earth. She turns away. Near India, these winds become south-west direction, that is why it is called south-west monsoon.
- When moist air rises, clouds and rain will form:When moist air rises, it cools. When cooled, water vapor changes into droplets. This is condensation. Then clouds form and it rains.
Monsoon not only changes the weather, it also changes the economy. Photo: PTI (file photo)
Which weather systems give rise to heavy rains in monsoon?
Monsoon rain is not the same every day. Some systems do this faster.
- Monsoon basin: A long low pressure area forms in North India. This is called monsoon trough. As it becomes stronger the rain increases. Break-like periods also occur when it becomes weak or slips.
- Low pressure area: Low pressure keeps forming in the Bay of Bengal. They move inwards. And provide good rains till central India.
- Effect of Mountains: The Western Ghats and the Himalayas help lift the air. When the air hits the mountain, it goes up. It gets cooler going up. Then it can cause heavy rain.
Will monsoon arrive on June 4?
The date of monsoon is not the same every year. Sometimes this comes first. Many times late. The normal onset of monsoon in Kerala is often considered to be around early June. There is a forecast of arrival of monsoon in Kerala on 4th June. The final and official information depends on the updates of the Meteorological Department. In practice, the arrival of monsoon means that for a few days continuous rain, wind and cloud patterns are seen as per the prescribed standards.
Monsoon, farmers, cities, and everyday life
Monsoon does not just change the weather. It also changes the economy. The time of sowing is related to monsoon. Kharif crops benefit from timely rains. Ponds, dams, and groundwater recharge depend on the monsoon. Waterlogging is common in cities due to heavy rains. Traffic and local transport is affected.
There are mainly two monsoons in India. The south-west monsoon is the heaviest rainy season. It operates due to the difference in pressure and temperature. Moist winds move from high pressure to low pressure. Monsoon arrives earlier in Kerala because it is on the way to the Arabian Sea. In this way, the Western Ghats raise the air and cause quick rains.
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