Question

Consider tropical high-level clouds and low-level stratus clouds with bases at 12 km and 1 km above the surface of the Earth, respectively. Which of the following statement(s) is/are correct?

• A. High clouds are composed of ice crystals.
• B. High clouds have a larger albedo than low clouds.
• C. High clouds have a net warming effect on climate.
• D. Low clouds have a net warming effect on climate.

Hint:

High clouds have a warming effect because they trap heat, whereas low clouds tend to reflect sunlight, leading to a cooling effect on the Earth's surface.

Answer 1

The Correct Option is A, C

High-level clouds, which are composed of ice crystals, have a net warming effect on the climate. These clouds, typically cirrus clouds, allow sunlight to pass through but trap outgoing infrared radiation, leading to a warming effect.
- Option (A) is true because high clouds are made of ice crystals due to their formation at higher altitudes where temperatures are below freezing.
- Option (C) is also correct, as high clouds generally cause a warming effect by trapping heat.
- Option (B) is false because high clouds have a lower albedo compared to low clouds, meaning they reflect less sunlight.
- Option (D) is incorrect as low clouds have a net cooling effect on the climate by reflecting more sunlight. Thus, the correct answers are (A) and (C).
Final Answer: \[ \boxed{(A), (C) \, \text{High clouds are composed of ice crystals, and high clouds have a net warming effect on climate.}} \]