Valonheijastuskykyä

Valonheijastuskykyä, often translated as albedo, is a measure of the diffuse reflection of solar radiation, usually expressed as a fraction or percentage. It describes how much of the incident solar energy is reflected back into space by a surface. Surfaces with high albedo, such as snow and ice, reflect a large proportion of sunlight, appearing bright. Conversely, surfaces with low albedo, like asphalt or dark forests, absorb more solar energy and appear darker.

The albedo of a surface is not static. It can change depending on factors such as the angle of incidence of sunlight, the spectral composition of the radiation, and the physical state of the surface. For example, a fresh snow cover has a very high albedo, but as the snow melts or becomes dirty, its albedo decreases. Similarly, vegetation can have varying albedo throughout the seasons.

Albedo plays a crucial role in regulating Earth's temperature and climate. Areas with high albedo reflect more solar radiation, contributing to cooler temperatures. Conversely, areas with low albedo absorb more radiation, leading to warmer temperatures. Changes in albedo, such as those caused by deforestation or the melting of polar ice caps, can have significant feedback effects on global climate patterns, influencing energy balance and contributing to phenomena like global warming. Understanding and measuring albedo is therefore important for climate modeling and environmental studies.