Albedo of Earth - Facts for UPSC Exam

A body or a surface reflects a fraction of light which is called ‘Albedo.’ There are two types of  Albedo – terrestrial albedo and astronomical albedo. The normal albedo is called normal reflectance (a measure of a surface’s relative brightness when illuminated and observed vertically.)

The topic ‘ Albedo’ is a factual topic under Geography syllabus for IAS Exam and has to be studied by aspirants carefully. This article will mention the details from the UPSC exam perspective helping them to understand what is Albedo and how does it affect climate change.

What is Albedo?

  • Albedo is the portion of solar energy reflected from the surface of the Earth back into space. It is a reflection coefficient and has a value of less than one.
  • When the solar radiation passes through the atmosphere, a certain amount of it is scattered, reflected and absorbed. The reflected sum of radiation is called the albedo of the earth.
  • Albedo is an important concept in climatology, astronomy, and environmental management.
  • It plays a major role in the energy balance of the earth’s surface, as it defines the rate of the absorbed portion of the incident solar radiation

Values of Albedo

  • Different surfaces have different values.
  • Albedo is higher in Snow or Ice.

Types of Albedo

There are two types of Albedo:

Type of Albedo Details about the Albedo
Terrestrial Albedo
  • The measurement of Earth’s albedo is known as Terrestrial Albedo.
  • The Terrestrial Albedo of Earth around 0.31 which is about two-thirds of the solar radiation reaching the Earth.
  • This figure (0.31) is dependent on many factors like an ocean, forest, clouds, deserts etc.
Astronomical Albedo
  • Astronomical albedo is the measure of the reflectivity of planets (excluding Earth), asteroids and other celestial bodies the albedo is an indicator of the surface and atmospheric characteristics of a celestial body.
  • It is important in the study of astronomy.

How does the Albedo of Earth affect Climate?

Albedo and Global Warming

  • The difference in the average albedo of Earth has an important influence on the temperature of the Earth.
  • If the average albedo is lower than the previous year’s albedo, it specifies that the amount of radiation absorbed is higher
  • This results in the rise in the temperature of the Earth.
  • Earth’s albedo is constantly measured using satellites to monitor global warming.

Frequently asked Questions about Albedo

Q1

What is Albedo?

Albedo is a non-dimensional, unitless quantity that indicates how well a surface reflects solar energy. Albedo varies between 0 and 1. Albedo commonly refers to the “whiteness” of a surface, with 0 meaning black and 1 meaning white.
Q2

Why is Albedo important?

Albedo is the reflectivity of a surface. A surface that has a high albedo reflects a lot of solar radiation from the sun back into the atmosphere, whilst a surface that has a low albedo reflects little solar radiation, absorbing it instead.

Related Links:

Climate Change
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Forces Affecting Wind

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