Test: Indian Monsoon - UPSC MCQ

• El Nino is the name given to the warm ocean currents along the Pacific coast of South America that arise every few years at about Christmas time.

• The El Nino phenomenon is a part of a chain of meteorological events that extends from the eastern Pacific to northern Australia, Indonesia and into the heartland of India.

• There is a rather weak correlation between El Nino and the Indian monsoon rains.

• Around September, with the sun fast retreating south, the northern landmass of the Indian subcontinent begins to cool off rapidly. With this air pressure begins to build over northern India, the Indian Ocean and its surrounding atmosphere still hold its heat.

• This causes the cold wind to sweep down from the Himalayas and Indo-Gangetic Plain towards the vast spans of the Indian Ocean south of the Deccan peninsula. This is known as the Northeast Monsoon or Retreating Monsoon.

In South India, rainfall decreases away from the Eastern Ghats  is false. The correct geographical pattern is that rainfall decreases from the Western Ghats towards the East. The Western Ghats block the moisture-laden South-West monsoon winds, leading to heavy rainfall on the western side, while the regions to the east (like the Deccan Plateau) receive less rainfall.

• Southwest monsoon is the main mechanism through which nearly all Indian landmass experiences rainfall. It accounts for nearly 80% rainfall of whole India.

• The vast size of the Indian continent helps in developing the thermal gradient necessary to attract the vapour laden air from the sea.

• Very high and extensive mountain systems of the Himalayas in the north, extending in an east-west direction, thus posing a formidable physical barrier between tropical and polar air masses.

• These barriers induce the precipitation of water from moisture-laden air. As the air climbs up the Himalayas their moisture retention capacity decreases due to cooling effect and this results into high rainfall.

• The southwest monsoon brings rains towards the end of summer as the high pressure built in the Indian Ocean pushes the wind masses towards the low pressure formed on land.

• It’s the temperature variation between the sea and the landmass – sea air being cooler and land being warmer – that causes the action. Also, we have to take an important factor called Temperature Gradient into consideration.

• It is the Temperature Variation Between The landmass and the surrounding sea.

Monsoon may be considered as large scale sea breezes, because of seasonal heating. The south west monsoon brings rain towards the end of summer It arrives in two branches - The way of Bengal branch and the Arabian sea branch.

• The southwest Monsoon brings rains towards the end of summer as the high pressure built in the Indian Ocean pushes the wind masses towards the low pressure formed on land.

• The southwestern summer Monsoons occur from July through September. Northern and central Indian subcontinent heats up during the hot summers.

• This causes a low-pressure area over the northern and central Indian subcontinent. To fill this void, the moisture-laden winds from the Indian Ocean rush into the subcontinent.

• These winds, rich in moisture, are drawn towards the Himalayas. The Himalayas act like a high wall, blocking the winds from passing into Central Asia and forcing them to rise. As the clouds rise their temperature drops and precipitation occurs.