How is albedo expressed?

Albedo is a measure of the reflectivity of a surface, particularly in relation to solar radiation. It quantifies how much sunlight is reflected off a surface compared to how much is absorbed. This measurement is typically expressed as a ratio ranging from zero to 1.0, where 0 indicates that no sunlight is reflected (the surface absorbs all incoming solar radiation), and 1.0 represents a surface that reflects all sunlight (absorbing none).

Understanding albedo in this way allows for comparisons between different surfaces, such as ice, water, grass, and urban materials, providing insight into their potential effects on temperature and climate. Surfaces with high albedo, like fresh snow, contribute to cooling by reflecting much of the sunlight, whereas surfaces with low albedo, like asphalt, absorb more heat, contributing to warming.

While albedo can be expressed as a percentage, which conveys the same information as a decimal ratio, the standard scientific practice often uses the ratio format to simplify calculations and discussions in environmental science and architecture. The temperature scale and qualitative assessments do not directly convey the concept of reflectivity in a quantifiable manner applicable to albedo.