Albedo is defined as the fraction of solar radiation reflected by a surface.

Albedo is defined as the fraction of solar radiation reflected by a surface.

• A. The fraction of solar radiation reflected by a surface
• B. The amount of infrared radiation absorbed by the atmosphere
• C. The rate of solar energy reaching the surface
• D. The density of surface features

Answer: (A)

Albedo is a measure of how reflective a surface is, specifically the portion of incoming solar radiation that a surface reflects back rather than absorbs. It is defined as the fraction of solar radiation reflected by a surface, and it can be expressed as a number between 0 and 1 (or as a percent). For example, fresh snow has a high albedo because it reflects most of the sun’s energy, while dark asphalt has a low albedo because it absorbs much of the energy. This concept is central to understanding how different surfaces influence the Earth's energy balance and climate. The chosen definition fits best because it directly describes the proportion of reflected solar radiation. The other options describe different ideas: infrared absorption by the atmosphere pertains to the greenhouse effect and atmospheric heat trapping, not surface reflectivity; the rate of solar energy reaching the surface refers to solar irradiance or insolation, not reflectivity; and the density of surface features is unrelated to how much light is reflected.

Albedo is a measure of how reflective a surface is, specifically the portion of incoming solar radiation that a surface reflects back rather than absorbs. It is defined as the fraction of solar radiation reflected by a surface, and it can be expressed as a number between 0 and 1 (or as a percent). For example, fresh snow has a high albedo because it reflects most of the sun’s energy, while dark asphalt has a low albedo because it absorbs much of the energy. This concept is central to understanding how different surfaces influence the Earth's energy balance and climate.

The chosen definition fits best because it directly describes the proportion of reflected solar radiation. The other options describe different ideas: infrared absorption by the atmosphere pertains to the greenhouse effect and atmospheric heat trapping, not surface reflectivity; the rate of solar energy reaching the surface refers to solar irradiance or insolation, not reflectivity; and the density of surface features is unrelated to how much light is reflected.