MONSOONS

• Monsoon in India is a significant weather phenomenon that brings relief from the scorching summer heat and plays a crucial role in the country's agriculture and economy.
• It is characterized by a seasonal reversal of wind patterns and the arrival of heavy rainfall over the Indian subcontinent.
• The Indian monsoon season typically lasts from June to September, divided into two phases: the Southwest Monsoon and the Northeast Monsoon.
• The Southwest Monsoon is the primary monsoon season and is responsible for the majority of India's rainfall.
• It occurs when moisture-laden winds from the Indian Ocean and the Arabian Sea sweep across the subcontinent.

• The monsoon's onset was delayed this year due to interactions between typhoons and cyclones, particularly Cyclone Biparjoy.
• This delay postponed the arrival of the monsoon in Mumbai by nearly two weeks. Interestingly, for the first time in over half a century, the monsoon arrived simultaneously in Mumbai and Delhi, resulting in an exaggerated curvature of the monsoon trough over northwest India.

4. Patchy Distribution of Rainfall

• Although the deficit caused by the delayed onset has been largely compensated, the distribution of rainfall remains patchy.
• Excess rainfall has been observed in the northern Western Ghats and northwest India, while deficits are seen in a horseshoe pattern from Uttar Pradesh to Odisha and extending into Chhattisgarh, Madhya Pradesh, and Maharashtra.
• Some areas in Himachal Pradesh experienced extreme heat alongside heavy rainfall.

Image Source: Down to Earth

5.1. Differential Heating

• The differential heating of land and water is a significant factor in the formation of monsoons.
• During summer, the landmass in India heats up more quickly than the surrounding oceans, creating a low-pressure area.
• This low pressure attracts moisture-laden winds from the Indian Ocean, resulting in the southwest monsoon.

5.2. Himalayan Mountain Range

• The presence of the Himalayas plays a crucial role in influencing monsoons.
• The mountains act as a barrier, forcing the moist winds to rise and cool.
• As a result, the moisture condenses and leads to heavy rainfall on the windward side (southern slopes) of the Himalayas.

5.3. El Nino and La Nina

• El Nino and La Nina are part of a natural climate cycle in the Pacific Ocean that can affect monsoons in India.
• El Nino refers to the warming of the central and eastern equatorial Pacific, which can disrupt monsoon patterns and reduce rainfall in India.
• Conversely, La Nina, characterized by the cooling of the same region, can enhance the monsoon and lead to increased rainfall.

5.4. Indian Ocean Dipole (IOD)

•  The Indian Ocean Dipole is another climate phenomenon that can influence monsoons.
• It refers to the temperature difference between the eastern and western parts of the Indian Ocean.
• Positive IOD conditions (warmer waters in the east) are associated with stronger monsoons, while negative IOD conditions (warmer waters in the west) can weaken the monsoons.

5.5. Land and Sea Breezes

• The differential heating of land and water also leads to the formation of local land and sea breezes.
• During the day, the land heats up faster than the ocean, resulting in a low-pressure area over the land.
• This draws in cool sea breezes from the nearby ocean, bringing some relief from the heat.
• At night, the land cools faster, creating a high-pressure area, and leading to land breezes.

6. Conclusion

• The monsoon is a vital natural phenomenon that shapes the lives and livelihoods of millions of people.
• Its arrival brings relief from the scorching heat of summer, replenishes water resources, and sustains agricultural activities.
• While the monsoon presents challenges, it also offers opportunities for economic growth, cultural celebrations, and the beauty of lush green landscapes.
• Understanding and managing the monsoon are crucial for ensuring the well-being and resilience of societies in monsoon-affected regions.