Difference Between Albedo and Reflectance (With Table)

Albedo and reflectivity are two key terms in electromagnetic wave reflection. Both concepts are extremely important in science such as astronomy for the transmission of long, short FM wavelength Radio waves, in chemistry for studying effects of EM waves created by vibrations between the magnetic field and electromagnetic field, in geology for studying Electromagnetic Radiation, and even in biology.

Albedo vs Reflection

The main difference between Albedo and Reflectance is that The Albedo of an object is a measure of how efficiently it reflects light. On the other hand, The ratio of the reflected radiant flux to the incident radiant flux on a surface is called Reflectance.

Albedo is a measure used to determine how much radiation is reflected from a surface. It’s a comparison of the quantity of radiation reflected from a surface with the amount of radiation that strikes it. This concept also refers to the amount of energy emitted by electromagnetic waves that are reflected in the source.

The correlation of the quantity of light leaving a target to the amount of light striking the target is known as Reflectance. Reflectance doesn’t have any units. Reflectance is a concept that is more commonly used in science that can be in the form of a microscope, which uses mirrors to reflect light and study the specimen under microscope and engineering field to study the effects of electromagnetic Reflectance is based on the thickness of the substance.

Comparison Table Between Albedo and Reflection

Parameters of Comparison AlbedoReflectance
DefinitionAlbedo is a measure used to determine how much radiation is reflected from a surface.The correlation of the quantity of light leaving a target to the amount of light striking the target is known as Reflectance.
PropertiesAlbedo is used in describing the properties of planets, satellites, and asteroids.Reflectance doesn’t describe the specific properties, It describes functions of frequency, the wavelength of light, polarization, etc.
UseAlbedo is used in the field of astronomy, Geology, etc.Reflectance is used in the field of science and engineering.
DependencyAlbedo does not depend on the thickness of the medium.Reflectance depends on the thickness of the substance.
ExampleAn example of Albedo is snow and ice, as they are non-reflective.An example of Reflectance can be a microscope, which uses a mirror to reflect light.

What is Albedo?

Albedo is a measure used to determine how much radiation is reflected from a surface. It’s a comparison of the quantity of radiation reflected from a surface with the amount of radiation that strikes it. This concept also refers to the amount of energy emitted by electromagnetic waves that are reflected in the source.

In astronomy, there are two types of Albedos, the Normal Albedo and the other is the Bond Albedo. The Normal Albedo is reflected from a surface where both directions (i.e., the illumination direction and the viewpoint are perpendicular). The Bond Albedo is the small part of the fragment of solar radiation reflected into space from the Earth’s surface.

Albedo is also used in astronomy to determine the imprecise size of objects in the solar system. Because asteroids gravitate to be small and distant, they become visible as points of light to astronomers. Consequently, astronomers cannot directly measure their size. Astronomers instead use the perceivable brightness, along with the object’s Albedo and distance from Earth, to evaluate the object’s size.

Albedo is an aggregate that indicates how successfully a material reflects solar radiation. Albedo is measured in decimal between 0 and 1. A value of 0 is said to be a perfect absorber that does not reflect any radiation. A value of 1 specifies the material that reflects all radiation, or in other words a perfect reflector.

What is Reflectance?

Reflectance is defined as The correlation of the quantity of light leaving a target to the amount of light striking the target. Reflectance doesn’t describe the specific properties, It describes functions of frequency, the wavelength of light, polarization, etc.

Reflectance is the ratio of the reflected transmitted energy of a surface to the incident transmitted energy of the surface. Since the Reflectance is a ratio of fluxes, it is unitless.

Reflectance depends on the thickness of the substance and is used in the field of science and engineering. Reflectance is used in studying soil science to determine the physical properties of soil, which includes particle size and moisture content. It is also important in astronomy, as reflectance spectroscopy is the main method for understanding the nature and composition of planets and asteroids.

The portion of an electric field reflected at a boundary or crossing point is called the reflection coefficient. And in turn, links to reflectance. Fresnel’s equation is used to calculate the reflection coefficient. It can be a real or a complex number. The surface’s reflectivity is said to be always positive and when the object’s reflectance is seen as zero it shows that there won’t be any reflection of any electromagnetic Waves that hit or collide.

Main Differences Between Albedo and Reflectance

  1. Albedo is a measure used to determine how much radiation is reflected from a surface. whereas Reflectance is the ratio of the reflected transmitted energy of a surface to the incident transmitted energy of the surface.
  2. Albedo does not depend on the thickness of the medium. on the contrary, Reflectance depends upon the thickness of the substance.
  3. Albedo is used in describing the specific properties of planets, satellites, and asteroids. On the other hand, Reflectance doesn’t describe the specific properties, It describes functions of frequency, the wavelength of light, polarization, etc.
  4. Albedo is used in the field of astronomy, Geology whereas Reflectance is used in the field of science and engineering.
  5. Albedo is measured in decimal between 0 and 1. A value of 0 is said to be a perfect absorber that does not reflect any radiation. A value of 1 specifies the material that reflects all radiation, or in other words a perfect reflector. where Reflectance is a ratio of fluxes, it is unitless.

Conclusion

Albedo is a measure used to determine how much radiation is reflected from a surface. Whereas, Reflectance is the ratio of the reflected transmitted energy of a surface to the incident transmitted energy of the surface.

Albedo and reflectance, are crucial sensors for detect detecting objects’ domains. Albedo is considered to be the property of the surface, while reflectance is considered to be the connection between the two medium.

References

  1. https://curry.eas.gatech.edu/Courses/6140/ency/Chapter9/Ency_Atmos/Reflectance_Albedo_Surface.pdf
  2. https://www.osapublishing.org/abstract.cfm?uri=ao-25-3-431