Albedo Calculator
Compute albedo using validated scientific equations. See step-by-step derivations, unit analysis, and reference values.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Albedo = Reflected / Incoming Radiation
Where albedo is a dimensionless ratio between 0 and 1. Absorbed radiation equals incoming minus reflected. Planetary equilibrium temperature uses the Stefan-Boltzmann law.
Worked Examples
Example 1: Fresh Snow Surface Albedo
Problem:A snow-covered field receives 850 W/m2 of incoming solar radiation and reflects 680 W/m2. The measurement area is 200 m2. Calculate the albedo and absorbed energy.
Solution:Albedo = 680 / 850 = 0.80\nAbsorbed = 850 - 680 = 170 W/m2\nTotal absorbed = 170 x 200 = 34,000 W\nEnergy balance ratio = 170 / 850 = 0.20
Result:Albedo: 0.80 (80%) | Absorbed: 170 W/m2 | Total: 34,000 W
Example 2: Dark Ocean Surface
Problem:Open ocean receives 1,100 W/m2 of incoming solar radiation and reflects only 66 W/m2 over a 500 m2 area.
Solution:Albedo = 66 / 1100 = 0.06\nAbsorbed = 1100 - 66 = 1034 W/m2\nTotal absorbed = 1034 x 500 = 517,000 W
Result:Albedo: 0.06 (6%) | Absorbed: 1,034 W/m2 | Total: 517,000 W
Frequently Asked Questions
What is albedo and how is it measured?
Albedo is a dimensionless measure of how much incoming solar radiation a surface reflects back into space, expressed as a ratio between 0 and 1. A value of 0 means the surface absorbs all incoming radiation while a value of 1 means it reflects everything. Scientists measure albedo using pyranometers that detect both incoming and reflected shortwave radiation, or from satellite instruments such as CERES aboard NASA satellites. Ground-based measurements typically involve placing one pyranometer facing upward and another downward at one to two meters above the surface.
What surfaces have the highest and lowest albedo values?
Fresh snow has one of the highest natural albedo values, typically ranging from 0.80 to 0.90, meaning it reflects 80 to 90 percent of incoming solar radiation. Ocean water at low sun angles has an albedo of only about 0.06, making it one of the darkest natural surfaces on Earth. Dense forests generally have albedo values between 0.10 and 0.20, while deserts range from 0.30 to 0.40 depending on sand color and mineral composition. Clouds are also highly reflective with albedo values between 0.40 and 0.80 depending on their thickness and droplet size.
How does albedo affect global climate?
Albedo plays a critical role in regulating the Earth energy budget because it determines how much solar energy the planet absorbs versus reflects back to space. The global average albedo is approximately 0.30, meaning Earth reflects about 30 percent of incoming solar radiation. Changes in albedo due to melting ice sheets, deforestation, or urbanization can amplify or dampen climate warming through feedback loops. As Arctic sea ice melts, the darker ocean surface absorbs more heat which melts more ice, creating a powerful positive feedback known as the ice-albedo feedback.
What is the ice-albedo feedback loop?
The ice-albedo feedback is a positive climate feedback mechanism where changes in ice and snow cover amplify temperature changes in polar regions. When warming causes ice and snow to melt, they expose darker land or ocean surfaces with much lower albedo values that absorb more solar radiation. This causes further warming and additional melting in a self-reinforcing cycle that accelerates ice loss over time. This feedback is particularly important in polar regions where it contributes to Arctic amplification. Climate models consistently identify ice-albedo feedback as one of the most significant amplifying mechanisms in the climate system.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy