Question

The albedo of the earth’s surface is only about 4% yet the combined albedo of earth and atmosphere is 30%. Which set of conditions below explain why is this so?
A) High albedo of clouds, the low albedo of water
B) High albedo of clouds, high albedo of water
C) Low albedo of clouds, low albedo of water
D) Low albedo of clouds, high albedo of water

Answer 1

Hint: Albedo measures the light reflected by the surface without being absorbed. White areas reflect more light than darker areas, and hence white areas have a high albedo. Snow and ice have the highest albedos of any parts of the Earth's surface.

Complete answer: Albedo is the measure of solar radiation or sunlight reflected by the surface. Light coloured surfaces such as snowy hills have high albedo, whereas dark coloured surfaces such as roads have a low albedo. The surface of the earth has numerous albedos that combine to form a single albedo. Cloud and water albedo have a significant effect on atmospheric albedo. Water reflects only 10% of incoming radiations resulting in a low albedo, whereas clouds have albedo from a minimum 10% to 90% depending on the liquid water, drop size and thickness of the cloud. This combined high albedo of clouds and low albedo of water gives an atmospheric albedo value of 30%. The amount of light reflected by the atmosphere without being absorbed is 30%. The higher value of cloud albedo indicates that clouds reflect a large amount of solar radiation, and low value of water albedo indicates water reflects a small amount of solar radiation.
Hence, the correct answer is option A.

Note: Albedo plays a significant role in maintaining the climate of the earth. If the albedo is low, more light is absorbed and the temperature of the area rises up, and if the albedo is high, more light is reflected and the temperature of an area decreases.