Solar Radiation and What Happens To It

Summary

This video explains the fundamentals of solar energy, focusing on the electromagnetic spectrum, including ultraviolet, visible, and infrared radiation. It discusses how different wavelengths of radiation interact with the Earth's atmosphere and surface, highlighting absorption, reflection, scattering, and transmission processes. The script also covers the concepts of shortwave (solar) and longwave (terrestrial) radiation, the effects of ozone depletion, and the importance of understanding insolation patterns. Additionally, it explores how radiation impacts daily life, such as how cars heat up in the sun, setting the stage for a discussion on the greenhouse effect.

Takeaways

• 😀 The solar energy that reaches Earth is in the form of electromagnetic waves, which vary in wavelength.
• 😀 Wavelengths are measured in micrometers, and they can range from very short (ultraviolet) to very long (infrared).
• 😀 Physical geographers focus on three bands of the electromagnetic spectrum: ultraviolet radiation, visible light, and infrared radiation.
• 😀 Ultraviolet radiation has the shortest wavelengths and can be harmful to humans, animals, and plants.
• 😀 Ozone in the upper stratosphere absorbs most ultraviolet radiation, protecting life on Earth.
• 😀 Visible light, which is the portion of the spectrum our eyes can perceive, makes up about 47% of the radiation that reaches Earth.
• 😀 Infrared radiation, which makes up about 45% of the incoming radiation, is emitted by both the Sun (short infrared) and the Earth (long infrared).
• 😀 Solar radiation (shortwave radiation) differs in wavelength from the radiation emitted by Earth (longwave radiation).
• 😀 The term 'insolation' refers to incoming solar radiation and is not to be confused with 'insulation'.
• 😀 Solar radiation can be absorbed, reflected, scattered, or transmitted as it passes through Earth's atmosphere, affecting how much reaches the surface.

Q & A

What is the primary form of energy that reaches the Earth from the Sun?

The primary form of energy that reaches the Earth from the Sun is solar energy, which comes in the form of electromagnetic waves.

What are the three key bands of the electromagnetic spectrum that physical geographers focus on?

The three key bands are ultraviolet radiation (0.01 to 0.4 micrometers), visible light (0.4 to 0.7 micrometers), and infrared radiation (0.7 micrometers to 1000 micrometers or 1 millimeter).

How does ozone protect us from ultraviolet radiation?

Ozone in the upper stratosphere absorbs ultraviolet radiation and re-emits it as infrared heat, reducing the amount of UV radiation that reaches the Earth's surface.

What are the differences between shortwave and longwave radiation?

Shortwave radiation refers to solar radiation emitted by the Sun, including ultraviolet, visible, and short infrared radiation. Longwave radiation, or terrestrial radiation, is emitted by the Earth, primarily in the form of thermal infrared radiation.

What is 'insolation'?

Insolation refers to incoming solar radiation, or the total amount of solar energy that reaches the Earth from the Sun.

What happens to solar radiation as it travels through the Earth's atmosphere?

Solar radiation can be absorbed, reflected, scattered, or transmitted as it passes through the atmosphere. These processes reduce the amount of radiation that reaches the Earth's surface.

Why do different materials absorb radiation differently?

Different materials absorb radiation differently based on their properties. For example, ozone absorbs ultraviolet radiation, while water vapor and carbon dioxide absorb thermal infrared radiation. Earth's surface materials, like rocks, soil, ice, and snow, also vary in how well they absorb or reflect radiation.

How does reflection differ from scattering of radiation?

Reflection occurs when radiation is bounced back in the opposite direction without changing wavelength. Scattering, on the other hand, deflects radiation in many different directions, but the wavelength remains unchanged.

Why do we experience higher temperatures inside a car parked in the Sun?

Shortwave radiation (visible light) passes through car windows, where it is absorbed by the interior materials. These materials then re-emit the absorbed energy as longwave infrared radiation (heat), which is trapped inside because the windows do not transmit infrared radiation well.

What role do color and material play in the absorption and reflection of radiation?

Color and material properties affect how much radiation is absorbed or reflected. For example, black surfaces absorb more visible light and become hotter, while white surfaces reflect more light and stay cooler.