State PCS

Edit Template
Edit Template

Heat & Temperature

The Earth’s surface temperature is controlled mainly by solar heating which happens from dawn to sunset. During the typical day the surface heats and during.....Heat and temperature...

The Earth’s surface temperature is controlled mainly by solar heating which happens from dawn to sunset. During the typical day the surface heats and during the night it cools. Exceptions to this happen during unusual wind events, where warm or cold air moves over the surface.

  • Changes in the surface temperature heat or cool the air above, which leads to air movement (wind).
  • Solar heating of the Earth’s surface is uneven because land heats faster than water, and this causes air to warm, expand and roise over land while it cools and sinks over the cooler water surface.
  • Earth intercepts only one in two billion partsof solar radiation. This intercepted  radiation  is called Insolation. It is the proportion of solar energy received or intercepted by earth.
  • Some heat within the core and mantle is transferred to the surface and ocean bottoms through volcanoes, springs and geysers. But this heat received at the surface form interiors of the earth is negligible compared to that received from sun.
  • Earth receives Sun’s radiation (heat) in the form of short waves which are of electromagnetic nature.
  • The earth absorbs short wave radiation during daytime and reflects back the heat received into space as long-wave radiation during night.
  • The insolation is not constant over the surface of the Earth — it is concentrated near the equator because of the curvature of the Earth.
Heat Budget :
  • The earth receives a certain amount of Insolation (short waves)and gives back heat into space by terrestrial radiation (longwave radiation). Through this give and take, or the heat budget, the earth maintains a constant temperature.
  • The energy flows and the storage in and between each of the Earth’s subsystems involve many components
  • The total energy available to drive all climate processes comes mainly from the distribution of solar radiation arriving and leaving the Earth.
  • To maintain a constant global average temperature, all of the sun’s radiation that enters Earth’s atmosphere must eventually be sent back to space. This is achieved through Earth’s energy balance.
  • The 70% of the sun’s energy that is absorbed by the surface, clouds, and atmosphere causes warming.
  • Most of the energy emitted from the earth’s surface does not go directly out to space. This emitted energy is reabsorbed by clouds and by the gases in the atmosphere.
  • The majority of the energy is absorbed by the greenhouse gases, methane, nitrous oxide, ozone, carbon dioxide and water vapor. These gases constantly emit the sun’s energy back into the atmosphere and keep the Earth at a habitable temperature. Eventually, most of the energy makes its way back out to space and Earth’s energy balance is sustained.
Albedo :
  • Albedo is another name for reflectivity determines how much sunlight will be absorbed and warm the surface compared to another surface that reflects most of the light and does not change temperature.
  • Something that appears white reflects most of the light that hits it and has a high albedo, while something that looks dark absorbs most of the light that hits it, indicating a low albedo.
  • Gases and particles in the atmosphere allow about half of the solar rays to pass through to the Earth’s surface. However, not all of it passes directly through to the surface uninterrupted.
  • Much of it – virtually all of it on a cloudy day – arrives as diffuse radiation, having been scattered by atmospheric particles and molecules.
  • About one third of the total of the Sun’s radiant energy that reaches the Earth eventually hits the surface without being scattered and about 25% reaches the surface as diffuse radiation.
  • At the surface, about 85% of the total amount is absorbed.
  • Over dark a surface such as the oceans, more than 90% is absorbed.
  • In the seas or in very wet, vegetated areas this absorbed heat is used to evaporate water.
  • Over bright surfaces, such as deserts and snowfields, 40-80 percent is reflected.

Heat & Temperature,Heat & Temperature

Read more : Weather & Climate

Demo Class/Enquiries

blog form

More Links
What's New
IAS NEXT is a topmost Coaching Institute offering guidance for Civil & Judicial services like UPSC, State PCS, PCS-J exams since more than 10 years.
Contact Us
Social Icon

Copyright ©  C S NEXT EDUCATION. All Rights Reserved