Definition
The ratio of the amount of solar radiation reflected by a surface to the amount of solar radiation that strikes it, usually expressed as a percentage or decimal value between 0 and 1. A surface with a high albedo reflects most of the sunlight that hits it; a surface with a low albedo absorbs most of it.
Plain English
How much sunlight a surface bounces back instead of soaking up. Fresh snow bounces back a lot; dark asphalt bounces back very little.
Context Anchor
Seen in aviation weather discussions about surface heating, cloud reflection, snow cover, and temperature differences over different terrain.
Derivation
From the Latin albedo, meaning 'whiteness,' from albus ('white'). The original idea was simply how white or bright something appears — which corresponds directly to how much light it reflects.
Why Pilots Care
Affects calculations for surface temperatures, radiation fog formation, and runway conditions at night.
Analogy
A white shirt feels cooler in the sun than a black shirt because it reflects more sunlight. Albedo is the same idea applied to the ground, clouds, snow, water, or other surfaces.
Grounding Statement
Picture flying over a patchwork of dark plowed fields and bright snow-covered fields on a sunny day. The dark fields absorb sunlight and warm the air above them; the snow reflects sunlight and stays cool. That difference in albedo is what makes the air bumpy as you cross between them.
Intuition Check
Albedo is not the same as temperature. It describes how much sunlight a surface reflects, which then affects how much that surface may heat up.
Example Sentence 1
The high albedo of the snow-covered terrain reduced surface heating and weakened thermal activity that afternoon.
Example Sentence 2
The pilot reviewed albedo values when assessing the likelihood of frost forming on the runway overnight.