Peegeldusmäär

Peegeldusmäär, also known as albedo, is a measure of the reflectivity of a surface. It is defined as the ratio of the amount of electromagnetic radiation reflected by a surface to the amount of radiation that strikes it. Albedo is typically expressed as a dimensionless fraction or a percentage, ranging from 0 (perfectly absorbing) to 1 (perfectly reflecting).

Different surfaces have varying albedo values. For instance, fresh snow has a very high albedo (around 0.8-0.9), meaning it reflects most of the sunlight that hits it. Dark surfaces, like asphalt or dark soil, have low albedo (around 0.05-0.15), absorbing a significant portion of incoming radiation. Water bodies generally have a moderate albedo, which can vary depending on the angle of the sun and the presence of waves. Vegetated areas also exhibit a range of albedo values, influenced by the type of vegetation and its condition.

Albedo plays a crucial role in Earth's energy balance. Surfaces with higher albedo reflect more solar radiation back into space, contributing to cooling. Conversely, surfaces with lower albedo absorb more solar energy, leading to warming. Changes in land cover, such as deforestation or the expansion of urban areas, can alter the average albedo of a region, potentially impacting local and global climate patterns. The concept of albedo is also applied in various fields, including remote sensing, climate modeling, and the design of energy-efficient buildings.