Lesson 4 Earth’s Radiation Budget Sci 20F

S2-4-02 Outline factors influencing the Earth’s radiation budget.Include: solar radiation, cloud cover, surface reflection (albedo), absorption, latitude

Read Science Power 10 p. 423 – 426 and make notes:

Radiant energy takes the form of electromagnetic waves Vary in wavelengths Solar radiation includes all visible light (ROYGBIV) as well as a little Ultraviolet (UV) and Infrared

(IR) All forms of life on Earth depend on solar energy (radiant energy from the Sun) Solar energy drives all weather systems Solar constant is the amount of energy that reaches Earth’s outer atmosphere (1367 J/m2s) –

only applies to rays that hit perpendicularly Solar energy is either reflected or absorbed by either the atmosphere or the Earth’s surface All objects emit radiation – cooler objects emit radiation with longer wavelengths Earth’s radiation lies within the infrared range Earth maintains an energy and temperature balance Solar radiation is emitted as infrared radiation – this drives weather systems

The Earth's Radiation Budget

The Earth's Radiation Budget is how much of the sun's energy is absorbed by the Earth versus how much of it is reflected back out to space.

In total, approximately 70% of the sun's energy is absorbed while 30% isreflected.

If the Earth and its atmosphere keep more solar energy than it sends back to space, the Earth will warm up.

If more energy is sent back to space than is kept by the Earth and its atmosphere, the Earth will cool down.

Scientists think of the Radiation Budget in terms of a see-saw or balance.When absorbed sunlight and reflected energy balance each other, the Earth's temperature doesn't change - the radiation budget is in balance. This is called Radiative Equilibrium.

The ozone layer filters out/reflects many of the sun's harmful rays andprevents some sunlight from reaching the earth.

The heat produced by the Sun travels to the Earth as waves known as electromagnetic waves. These waves come in a variety of lengths. The name given to the full range of all the wavelength is the electromagnetic spectrum.

The Albedo Effect

Read this article at home: https://www.worldatlas.com/what-is-albedo.html

Albedo video (4 min): https://www.youtube.com/watch?v=sCxIqgZA7ag

Albedo is a latin word meaning “whiteness”

The term albedo refers to the amount of solar energy that gets reflected off of the Earth and lands back in space.

The Albedo of CloudsThe albedo of the Earth depends on whether there are clouds in the sky.

• Clouds reflect more sunlight back into space than blue sky does.

• The albedo of a cloud depends on many factors including: the height of the

cloud, its size and the number of water droplets inside the cloud.

The color of a cloud, from bright white to dark grey, depends on the waterdroplets in the cloud.

• Big droplets have a large surface area and reflect more light than small

droplets.

• The presence of large numbers of water droplets leads to bright white clouds.

Quick Cloud Type Refresher

Discuss: If you are under a large cumulonimbus cloud, would it look the same from underneath it as it would from space? Or would it look different? Explain.

Would it be the same situation for a different type of cloud? Explain.

Answer: If you are under a big cumulonimbus cloud it's dark because the sunlight can't pass easily through the clouds. From space, however, the same cloud would look bright white because it actually has a high albedo. In contrast, a cirrus cloud is nearly transparent to sunlight but looks greyfrom space because it has a low albedo.

Lesson 4 Earth’s Radiation Budget Sci 20F

S2-4-02 Outline factors influencing the Earth’s radiation budget.Include: solar radiation, cloud cover, surface reflection (albedo), absorption, latitude

Read Science Power 10 p. 423 – 426 and make notes:

Notes:

The Earth's Radiation Budget

The Earth's Radiation Budget is how much of the sun's energy is absorbed by the _________ versus how much of it is reflected back out to _____________.In total, approximately ____% of the sun's energy is absorbed while ____% is reflected.

If the Earth and its atmosphere keep more solar energy than it sends back to space, the Earth will ___________ __________.

If more energy is sent back to space than is kept by the Earth and its atmosphere, the Earth will _____________ ____________.

Scientists think of the Radiation Budget in terms of a ____________ or ____________.When absorbed sunlight and reflected energy balance each other, the Earth's _____________ doesn't change - the radiation budget is in balance. This is called ________________ _______________.The _____________ layer filters out/reflects many of the sun's harmful rays and prevents some sunlight from reaching the earth.

The heat produced by the Sun travels to the Earth as waves known as ________________________ __________. These waves come in a variety of lengths. The name given to the full range of all the wavelength is the _______________ ________________.

The Albedo Effect

Read this article at home: https://www.worldatlas.com/what-is-albedo.html

Albedo video (4 min): https://www.youtube.com/watch?v=sCxIqgZA7ag

Albedo is a latin word meaning “_______________”

The term albedo refers to the amount of _________ energy that gets _______________ off of the __________ and lands back in ___________.

The Albedo of Clouds

The albedo of the Earth depends on whether there are _____________ in

the sky.

• Clouds ______________ more sunlight back into ___________ than

blue sky does.

• The albedo of a cloud depends on many factors including: the

______________ of the cloud, its ___________ and the number of

_____________ _____________ inside the cloud.

The color of a cloud, from bright white to dark grey, depends on the

___________ _______________ in the cloud.

• Big droplets have a __________________ surface area and

____________ more light than small droplets.

• The presence of large numbers of water droplets leads to

_____________ ____________ clouds.

Quick Cloud Type Refresher

Discuss: If you are under a large cumulonimbus cloud, would it look the same from underneath it as would from space? Or would it look different? Explain.

Would it be the same situation for a different type of cloud? Explain.