Question

Identify the correct statements:
Statements:
A. Eddy diffusion is a dominant mixing process in the stratosphere.
B. Height of the troposphere at poles is less than that over the equator.
C. Mean free path of molecules in the mesosphere is longer than that in the troposphere.
Choose the correct answer from the options given below:

• A. (A) and (B) only
• B. (B) and (C) only
• C. (A) and (C) only
• D. (A), (B) and (C)

Hint:

Remember that atmospheric mixing mechanisms vary by altitude: the troposphere relies on turbulence and convection, while molecular diffusion becomes significant in the upper layers like the mesosphere.

Answer 1

The Correct Option is B

1. Statement A is incorrect. Eddy diffusion is not the primary mixing mechanism in the stratosphere; molecular diffusion predominates at these higher altitudes.
2. Statement B is correct. The troposphere is shallower at the poles (approximately \( 8{-}10 \, \text{km} \)) compared to the equator (approximately \( 16{-}18 \, \text{km} \)), a result of temperature variations and atmospheric dynamics.
3. Statement C is correct. Molecular mean free path lengthens with increasing altitude due to decreased air density, making it longer in the mesosphere than in the troposphere.

Therefore, statements (B) and (C) are correct.