Q1.
Udhagamandalam (Ooty) and Coimbatore are almost at the same latitude. The range of summer temperatures in Ooty is 10–25° while that in Coimbatore is 25–38°. Why do you think there is such a difference in temperature between these two places?
Answer
Because of altitude. Latitude is the same for both, so it cannot be the reason — the one factor that differs sharply is height above sea level.
Ooty — up in the Nilgiri hills, at roughly 2,200 m
Coimbatore — on the plain at the foot of the hills, at roughly 400 m
Difference in summer maximum = 38° − 25° = 13°
Difference in summer minimum = 25° − 10° = 15°
Coimbatore — on the plain at the foot of the hills, at roughly 400 m
Difference in summer maximum = 38° − 25° = 13°
Difference in summer minimum = 25° − 10° = 15°
Both reasons from page 50 apply:
- At Ooty's height the atmospheric pressure and air density are lower, and less dense air is cooler.
- Ooty is much farther from the heated land surface of the plains, and it is the ground that warms the air.
Why this pair is such a good example: the two towns are barely 80 km apart and sit at almost the same latitude, so the Sun stands at the same angle over both. Everything a scientist would want to hold constant is constant, leaving altitude as the only explanation. That is exactly why Ooty became a hill station and Coimbatore did not.
Try This: compare any hill station near you with the nearest town on the plain — Shimla with Chandigarh, Darjeeling with Siliguri, Mahabaleshwar with Pune. You will find the same 10–15°C gap.