Question

Write a short note on the rainy season and the retreating southwest monsoon season.

Answer 1

Hint: Winds are heading back from the mainland to the Bay of Bengal during this retreating southwest monsoon season. During this season, the southern parts of India, mostly Tamil Nadu and Andhra Pradesh, receive rainfall. The winds of this Southwest Monsoon Season or the Rainy Season bring heavy rainfall to most parts of the country.

Complete Answer:
The rainy season – The season marked by the start of the monsoon is known as the south-western monsoon. It's sometimes called the rainy season.
- In the month of June, the Southwest Monsoon Season or the Rainy Season begins its voyage and continues until September.
- The onset and progress of the monsoon, where the winds blow from the Arabian Sea and the Bay of Bengal to the land, is visible this season.
- These winds bring along with them moisture. The rainfall begins when these winds approach or touch the mountain barriers.
- The high-pressure permanent cell in the Indian Ocean's South (East to Northeast of Madagascar in summer).

Factors that affect the monsoons of the south-west:
- The intense development of low pressure over the Tibetan Plateau.
- A persistent high-pressure cell in the Indian Ocean to the south.
- Subtropical stream of jets.
- Easterly African Jet or Eastern Tropical Jet.
- Convergence Zone Inter-Tropical (ITCZ).

The retreating southwest monsoon season - The south-westerly monsoon winds become weaker during the months of October-November and begin to withdraw from the skies of North India. The withdrawing monsoon is known as this process of the monsoon.
- The retreat of the monsoon season begins with the withdrawal of the southwest monsoon[mid-September-November] and lasts until the beginning of January.
- It is a 3-month long operation, beginning in October from the peninsula and by December from the extreme south-eastern tip.
- In mid-December, the south-western monsoons withdrew from the Coromandel coast
- The withdrawal of the monsoon that retreats is gradual and takes a longer time compared to the one that progresses.

Factors that affect the Retreat monsoons of the south-west:
- The development and strengths of high-pressure cells during winters over the Tibetan and Siberian Plateaus .
- Migration to the south of India from the Inter-Tropical Convergence Zone (ITCZ).
- High-pressure cells are migrating westward and weakening in the southern Indian Ocean.

Note: Intertropical Convergence Zone (ITCZ) –
- The ITCZ follows the sun in that the location varies from season to season. It travels north in the summer of the Northern Hemisphere and south in the winter of the Northern Hemisphere. The ITCZ is also responsible for the rainy and dry seasons in the tropics.
- The region near the equator with low pressure and converging, rising winds is known as the Intertropical Convergence Zone (ITCZ). Water vapor condenses as the air rises and cools in the ITCZ, creating clouds and falling like rain. This is where monsoon rainfall occurs.