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Albedo

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The albedo is a fraction of light reflected on a body or on a surface . It is a term commonly used in the area of astronomy to be able to describe the different reflective properties that planets , satellites and asteroids have . The term is seen as a way of expressing the ability of surfaces to reflect sunlight or heat from the sun.  Light colored surfaces return a large part of the sun’s rays to the atmosphere while dark surfaces are responsible forabsorb the sun’s rays.

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What is albedo?

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We call albedo the relationship that occurs between the light energy diffused through a surface through reflection and the incident energy , it is the one that reveals the radiation level of a surface.

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Definition

Albedo can be defined as a way of quantifying the amount of radiation that is reflected from the surface . It is a comparison that is made between the radiation reflected from the surface and the amount of radiation that hits it. This term is also used to refer to the amount of radiation that is produced by electromagnetic rays and by which it is therefore reflected.

It is part of the energy from sunlight that is returned to the atmosphere . These rays have a very important and significant effect on our climate . When the albedo rises, the universe reflects more light and, for this reason, it is sent back into space in higher levels of radiation so that the earth can cool down . The albedo is the one in charge of determining the level of heat that exists in the earth .

Explanation of the albedo effect

The explanation of this type of effect is actually quite simple to do. While a part of the solar radiation is reflected by means of the Earth through the water , the ground , the atmosphere and other types of surfaces; the other part of the radiation is absorbed by the planet, thus causing a warming effect . We must remember that the earth reflects part of the sun’s radiation through three main factors: the atmosphere , clouds and the earth’s surface.. The radiation that is reflected by this earth’s surface is what we know by the name of albedo . In this way then, we can say that albedo is the amount of solar radiation that can be returned to the atmosphere after it collides with the earth’s surface .

As measured

The planetary albedo is located at approximately 0.1 , which means that around 30% of the solar energy that enters part in the form of direct radiation towards space . The albedo of the continents is approximately 34% , and the albedo of the oceans is 26% and that of medium and low altitude clouds is between 50% and 70%.

Although the planetary scale has an energy balance equal to zero, in few places on earth do we find the balance in equilibrium . Some areas receive more energy than they emit ; and in others, more is emitted than they receive. The balances are in surplus until the parallels between 35º and 40º where the amounts are equal, and they become deficit.

It can also be measured as follows:

  • Value  “ 0” : if a score of zero is given, the surface is said to be very receptive to light , which means that the surface receives all the light that comes in contact with it. It is characterized by black surfaces.
  • Value “1” : this score is evidence that the surface does not absorb incoming light . It is characterized by white surfaces .

Planetary albedo

Some of the planets that contain albedo are as follows:

  • Earth : in its atmosphere determines the albedo of the planet. The albedo of water , from light in the sky, is low, about 10 percent, and that of most land areas , such as soil or sand , is also relatively low, ranging from 15 to 45 percent. percent. The exception is snow , which is most often found at the Earth’s poles. Snow reflects most of the light that hits it, leading to a high albedo of about 90 percent.
  • Mercury : composed primarily of aporous dark rock surface, it reflects very little light. Its atmosphere consists of 95 percent carbon dioxide , which is optically transparent and  does not contribute to the planet’s albedo at only 6 percent.
  • Saturn : It does not have a solid surface , so albedo is formed by gases in its atmosphere, hydrogen , helium, and other trace gases that combine to form clouds made of water vapor , ammonia, and ammonium hydro sulfide . These clouds reflect a significant amount of incident light, leading to a planetary albedo of 47 percent.
  • Mars : Its surface is mostly red soil that includescommon volcanic minerals and glass particlesso its albedo, at 29 percent, is dominated by the relatively dark surface.

Relationship with climate change

Global albedo has been found to have risen recently, and on a measurement scale, watts per square meter are now higher . This according to research by Anthony Watts. The universe is gradually warming due to deforestation and therefore better forest management must be adopted to mitigate the effects of albedo . Trees reduce the radioactive effects of solar reflection and we must also protect our wetlands and the fractions of the snow cover . The loss of the Arctic is a huge concern.

Many states advocate reforestation as the trees are darker and have low albedo emission rates . If you plant more trees, you are remunerated based on a system called a carbon credit . Clouds can sometimes reflect sunlight, but they can still keep warm, thus warming the Earth. Today, climate scientists and researchers are concerned that if global warming continues, the polar ice caps will melt and ocean water will absorb more sunlight., which will increase global warming. It is in this context that we must all work to find better models to curb its effect in the future. 

Other consequences of albedo

Other consequences that can occur with the affectation of the albedo of the earth are the increase in temperatures , which in turn can cause the planet to heat up more quickly. When the albedo of the Earth is reduced, the planet absorbs a greater percentage of the solar radiation it receives and this, together with the greenhouse effect , would accelerate the increase in temperatures.

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