Syllabus
GS Paper I – Geographical features and their location-changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
Context
What is causing widespread rainfall across India?
Widespread rainfall across India
Introduction
Widespread rainfall has been a significant weather phenomenon across India recently. For the first time this season, the southwest monsoon has become active over a large portion of the country, with rainfall reported in at least 80% of India. The monsoon, which was subdued during mid-June, gained momentum toward the end of June and covered the entire country by early July. This shift in weather patterns has implications for agriculture, water reservoirs, and overall climate dynamics.
Factors causing widespread rains
- Early Monsoon Onset:
- The monsoon arrived six days ahead of its normal schedule, covering the entire country.
- States like Delhi, Punjab, Uttarakhand, Uttar Pradesh, Himachal Pradesh, Rajasthan, and Jammu and Kashmir experienced rainfall in early July.
- Favorable Weather Systems:
- Throughout July, multiple weather systems maintained an active or vigorous monsoon:
- Southern peninsular, east, northeast, and central India regions benefited.
- Key contributors were moisture-laden westerly winds from the Arabian Sea.
- Throughout July, multiple weather systems maintained an active or vigorous monsoon:
- Monsoon Trough Position:
- The monsoon trough, extending between Pakistan and the Bay of Bengal, plays a crucial role.
- Its north-south oscillation affects rainfall distribution:
- Southward shift leads to increased rainfall in central, eastern, and peninsular India.
- Northward shift favors the Himalayan foothills but reduces rainfall elsewhere.
Weather systems which contributed to the widespread rainfall
- Offshore Trough:
- The off-shore trough, which develops along India’s coast during the monsoon, persisted between south Gujarat and north Kerala for over a week.
- This shallow trough of low pressure contributes to localized rainfall in coastal regions.
- Wind Shear Zone:
- Intermittently, a wind shear zone forms along latitudes 20°N between central and peninsular India.
- In this zone, winds move at varying velocities and directions, affecting weather patterns.
- Low Pressure System:
- A low pressure system developed over the west-central Bay of Bengal, near the Odisha coast.
- It subsequently moved over Chhattisgarh, Vidarbha, and southeast Madhya Pradesh, influencing rainfall distribution.
- ENSO Transition and La Niña Formation:
- The El Niño-Southern Oscillation (ENSO) is returning to a neutral phase.
- La Niña, characterized by cooling sea surface temperatures, is expected to form in the second half of the monsoon season.
- La Niña events occur every 3-5 years and can lead to increased rainfall and distinct weather patterns, sometimes resulting in floods.
Conclusion
The intricate interplay of various weather systems underscores the complexity of monsoon dynamics in India. As these factors converge, comprehensive meteorological monitoring and accurate forecasting become crucial. Understanding these patterns not only aids in predicting rainfall but also informs disaster preparedness, agricultural planning, and water resource management.
Source: IE
Related PYQ
Why is the South-West Monsoon called ‘Purvaiya’ (easterly) in Bhojpur Region? How has this directional seasonal wind system influenced the cultured ethos of the region? [UPSC Civil Services Exam – 2023 Mains]
Practice Question
Analyze the various weather systems contributing to the widespread rainfall across India, and explain how the potential formation of La Niña might influence monsoon patterns in India. [150 words]