Longwave radiation

Definition

Longwave radiation refers to the infrared radiation emitted by the Earth as it releases energy absorbed from solar radiation. This type of radiation typically has wavelengths longer than 4 micrometers, distinguishing it from shorter wavelengths of ultraviolet and visible light. Longwave radiation plays a crucial role in the Earth's energy balance and is essential for understanding processes like greenhouse warming and radiative transfer in the atmosphere.

5 Must Know Facts For Your Next Test

1. Longwave radiation is primarily emitted by the Earth's surface and atmosphere as it cools down after absorbing solar energy during the day.
2. The amount of longwave radiation emitted depends on the temperature of the emitting surface; warmer surfaces emit more longwave radiation according to Stefan-Boltzmann Law.
3. Greenhouse gases such as carbon dioxide and methane absorb longwave radiation, which leads to an increase in atmospheric temperature.
4. The balance between incoming shortwave radiation from the sun and outgoing longwave radiation from Earth is crucial for maintaining the planet's climate.
5. Variations in longwave radiation can significantly impact weather patterns and climate change over time.

Review Questions

• Explain how longwave radiation contributes to the greenhouse effect and its significance for Earth's climate.
  • Longwave radiation is vital for the greenhouse effect as it represents the energy that Earth emits after absorbing sunlight. Greenhouse gases like carbon dioxide trap some of this outgoing longwave radiation, preventing it from escaping into space. This process warms the atmosphere and helps maintain a stable climate. Without this mechanism, Earth would be much colder and less hospitable for life.
• Discuss the role of longwave radiation in radiative transfer and how it interacts with different atmospheric components.
  • Longwave radiation plays a key role in radiative transfer by interacting with various atmospheric components, including gases, aerosols, and clouds. As longwave radiation travels through the atmosphere, it can be absorbed by greenhouse gases, leading to warming. Additionally, clouds can both absorb and emit longwave radiation, influencing local weather conditions. This interaction is essential for understanding energy balance within the atmosphere.
• Evaluate how changes in greenhouse gas concentrations could alter the balance of longwave radiation and affect global climate patterns.
  • Increased concentrations of greenhouse gases enhance the absorption of longwave radiation, leading to more heat being retained in the atmosphere. This change disrupts the natural balance between incoming solar energy and outgoing longwave energy, resulting in an overall warming effect known as global warming. Such alterations can trigger significant shifts in global climate patterns, including altered precipitation rates, increased frequency of extreme weather events, and changes in ecosystems across the planet.

Related terms

Greenhouse Effect: The process by which certain gases in the Earth's atmosphere trap longwave radiation, preventing it from escaping into space and contributing to warming.

Radiative Transfer:

The process by which energy in the form of electromagnetic radiation is transmitted through a medium, such as the atmosphere, involving absorption, emission, and scattering.

Shortwave Radiation: Radiation emitted by the sun, primarily in the visible spectrum and near-infrared range, with wavelengths shorter than 4 micrometers.