Albedo of Earth
By : Neha Dhyani
Updated : May 16, 2022, 5:58
'Albedo' is defined as the reflection of a proportion of light by a body or a surface. The Albedo of Earth is classified into two types: Terrestrial Albedo and Astronomical Albedo. Normal Albedo is referred to as normal reflectance, which measures the surface's relative brightness when lighted and examined vertically. Whereas the overall fraction of solar radiation reflected back into space from a planetary surface is called the Bond Albedo.
The Albedo of Earth influences its climate by evaluating the amount of radiation it absorbs. The climatic and weather conditions could be influenced by the uneven heating of the Earth caused by differences in Albedo across the land, ice, and ocean surfaces.
What is Albedo in Geography?
- Albedo in Geography is the amount of solar radiation reflected back into space from the Earth's surface. It has a value less than one and is a reflection coefficient.
- As solar radiation traverses through the atmosphere, some of it gets dispersed, reflected, and absorbed. The sum of reflected radiation is referred to as the Albedo of Earth.
- It is critical to the energy balance of the Earth's surface because it determines the rate of absorption of incident solar radiation.
- The concepts and principles governing the Albedo Effect are essential in astronomy, climatology, and environmental sciences and management.
Values of Albedo of Earth
- Albedo is measured on a scale of 0 to 1, with 0 representing a dark body that absorbs all incident radiation and 1 representing a body that reflects all incident radiation.
- Due to cloud cover, the average Albedo of the Earth from the upper atmosphere, or Planetary Albedo, is 30–35 per cent, but it varies greatly regionally over the surface due to diverse geological and environmental factors.
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Types of Albedo of Earth
1. Terrestrial Albedo
- Terrestrial Albedo is the measurement of the Earth's Albedo.
- The Terrestrial Albedo of the Earth is approximately 0.31, which accounts for approximately two-thirds of the solar radiation reaching the Earth.
- This statistic (0.31) is affected by a variety of circumstances such as an ocean, forest, clouds, deserts, and so on.
2. Astronomical Albedo
- The reflectivity of planets (except Earth), comets, and other celestial objects are measured by Astronomical Albedo.
- The Albedo of a celestial body is a measure of its surface and atmospheric properties.
- It is necessary for the study of astronomy.
Effect of Albedo of Earth on the Climate Change
- The variance in the mean Albedo of the Earth has a significant impact on the planet's temperature.
- If the average Albedo is lower than the previous year's Albedo, it indicates that more radiation absorption rate has been on the higher end. As a result, the temperature of the Earth rises.
- Satellites constantly measure the Earth's Albedo to monitor global warming and climate change.
The Albedo of Earth is a measure of how much a substance reflects radiation. It is expressed as a decimal between 0 and 1. A low Albedo indicates a dark surface, whereas a high Albedo indicates a bright surface. Albedo is determined by a material's physical properties, notably, its surface properties.
FAQs on Albedo of Earth
Q1 What is the Albedo of Earth?
The Albedo of Earth of a surface is a non-dimensional, unitless number that indicates how well it reflects solar radiation. Its value ranges between 0 and 1.
Q2 How is the Albedo of Earth useful in Astronomy?
The Albedo of Earth is vital in astronomy for identifying hazy objects like asteroids, modelling the surfaces of faraway solar system bodies, and perhaps for exoplanet exploration.
Q3 How is Albedo of Earth different from emissivity?
The Albedo of Earth differs from emissivity as it considers the radiation reflected from a surface. In contrast, emissivity considers the radiation that a surface emits.
Q4 Where does the Albedo of the Earth peak out?
Snow and ice have the maximum Albedos of any surface on Earth. Some areas of Antarctica can reflect up to 90 per cent of received solar radiation.