What is the primary reason for the intensification of the monsoon trough over North India by the end of May?
- ((a))
Shift in wind patterns
- ((b))
Decrease in humidity
- ((c))
Increase in atmospheric pressure
- ((d))
High temperature in the region
Show Answer
High temperature in the region
The correct answer is 'High temperature in the region'
Key Points
- High temperature in the region:
- The primary driver for the intensification of the monsoon trough over North India is the intense heating of the landmass during the summer months (April, May, and June).
- By the end of May, the sun shines almost directly over the Tropic of Cancer, leading to exceptionally high temperatures in the North and Northwest parts of the Indian subcontinent.
- As the air heats up, it becomes less dense and rises, creating a strong low-pressure zone known as the monsoon trough.
- This low-pressure area becomes so intense that it effectively "pulls" the moisture-laden trade winds from the Southern Hemisphere across the equator toward the Indian landmass.
Additional Information
- Shift in wind patterns:
- While a shift in wind patterns (from North-East to South-West) is a characteristic of the monsoon season, it is a consequence of the pressure gradient created by high temperatures, rather than the primary reason for the trough's intensification.
- The shift occurs because the winds move from high-pressure areas over the ocean toward the low-pressure trough over the land.
- Decrease in humidity:
- A decrease in humidity is incorrect because, as the monsoon trough intensifies and the monsoon winds approach, the humidity in the atmosphere actually increases significantly.
- Dry conditions precede the trough's peak, but the intensification of the trough itself is what eventually brings the moisture.
- Increase in atmospheric pressure:
- This is the opposite of what happens. A trough is, by definition, an elongated region of low atmospheric pressure.
- An increase in atmospheric pressure would lead to stable, clear weather and would prevent the onset of the monsoon.
Important Points
- The monsoon trough is essentially the regional manifestation of the Inter-Tropical Convergence Zone (ITCZ) shifting northward during the Northern Hemisphere summer.
- In summer, the ITCZ moves from the equator toward the Ganga plains, usually positioned around 20°N-25°N latitude by July.
- The position and strength of this trough determine the distribution and intensity of rainfall across North India.
- The Thar Desert and the surrounding regions of Pakistan and Northwest India act as the core center of this thermal low-pressure system.










































