Skip to main content

Heat Budget of Earth

Image
By
Earth and its atmosphere are continuously receiving solar energy. Most of the solar energy reaches the surface of the earth in the form of short waves. Earth absorbs it and converts it into heat. Due to its special temperature, the earth sends the heat absorbed by terrestrial radiation back to the space through long waves.

Earth absorbs black body that means each and everybody whereas atmosphere is very selective, and it absorbs 85% of long waves and it is transparent for short waves, that transparency is known as atmospheric window.

In this way the earth does not store solar energy but sends the same amount of energy back to the space through terrestrial radiation. This exchange of energy is made possible by highly complex processes of radiation. This is the reason why the annual average temperature of the earth's surface remains constant. There is no significant change in it.

Let the temperature received at the upper surface of the atmosphere be 100 units. Out of this, only 51 units of heat reaches the earth. 49 units heat gets reflected in the atmosphere and space. 35 units of heat is converted into space even before reaching the surface of the earth. Out of this, 6 units are scattered in space (by dust-particle), 27 units are reflected by the clouds and 2 units are reflected by snow covered areas (Glacier) on the earth.

This reflected amount of solar radiation is called the Albedo (it is the ratio of incoming solar radiation to the outgoing solar radiation. In case of snow Albedo is 80% whereas in case of land it is 30-35%) of the Earth. Out of the remaining 65 units, 14 units of heat is absorbed by the atmosphere (water vapor). Thus, out of 100 units on the earth, only 51 units of heat reach the surface.
51 units absorbed by the earth are returned back to the atmosphere in the form of terrestrial radiation. Of these, 17 units are directly returned to space and 34 units are absorbed by the atmosphere. Out of these 34 units, 6 units are absorbed by the atmosphere itself, 9 units by convection process and 19 units as latent heat.

48 units absorbed by the atmosphere (14 units from solar heat and 34 units from terrestrial radiation) are returned to space. Thus, the heat received by the earth and its atmosphere is equal to the heat released by them. The balance of heat received by the earth and atmosphere and the loss of heat by them is called heat budget or heat balance.
Labels:

Comments

Post a Comment

Popular posts from this blog

The Geology and Formation of the Shiwalik Range: A Result of Tectonic Processes in the Himalayas.

By
The Shiwalik Range , also known as the Shivalik Hills or the Outer Himalayas , is a mountain range in northern India and southern Nepal. It is the southernmost and outermost range of the Himalayas. The formation of the Shiwalik Range is closely linked to the geological processes that shaped the Himalayan Mountain system. The Himalayas, including the Shiwalik Range, have been formed through the collision of the Indian and Eurasian tectonic plates over millions of years. Around 50 million years ago, the Indian plate, which was originally located south of the equator, began moving northward towards the Eurasian plate. As the Indian plate approached the Eurasian plate, it started to subduct beneath it. Subduction is the process where one tectonic plate sinks beneath another due to the difference in density. The subduction of the Indian plate led to the upliftment of the overlying sedimentary and crustal rocks, creating the Himalayas. The Shiwalik Range specifically formed during the ...
Post a Comment
Read more

Why is Earth called a Dynamic Planet

By
Earth is often referred to as a "dynamic planet" because it is constantly undergoing various dynamic processes and changes. These processes occur on different spatial and temporal scales, and they shape the planet's surface, atmosphere, and even its interior. Here are some reasons why Earth is called a dynamic planet: 01. Plate Tectonics : Earth's lithosphere, the rigid outer layer composed of tectonic plates, is in constant motion. This movement, known as plate tectonics, leads to the creation of mountains, the opening and closing of ocean basins, and the formation of earthquakes and volcanoes. It is a dynamic process that continuously reshapes the Earth's surface. 02. Earthquakes and Volcanoes : Earth is seismically active, with earthquakes occurring regularly around the world. These seismic activities are a result of the movement and interaction of tectonic plates. Volcanoes are also a consequence of plate tectonics, where molten rock (magma) rises to the surf...
Post a Comment
Read more