1 of 25

Lesson Plan 2 – Day 2

Earth’s Energy Budget

2 of 25

Bell Work: �We know that if the Sun kept inputting energy and it didn't go anywhere, then we would eventually be fried. What do you think happens to this energy? Why don't we all burn up?

3 of 25

Variables in the Energy Budget

Where on Earth

Pole vs. Equator

Reflection (albedo)

Material type

Clouds
Atmosphere
Absorption and Re-radiation

4 of 25

Sun emits radiation

Earth intercepts

sunlight

Input = Sunlight

^{(short wave)}

Output= ?

30% is reflected

5 of 25

Follow the Energy

6 of 25

Energy Moves in Three Ways

Conduction • Convection • Radiation

7 of 25

Radiation seen in Infrared Images

8 of 25

Radiation

When energy is absorbed by an object (rock, water, building), the temperature of the object increases.
All objects emit radiation. The amount and wavelength range is dependent on the temperature of the object.

As the temperature increases (hotter), the wavelengths emitted by the object decreases (becomes shorter wavelengths).

9 of 25

Objects Radiate Heat

Earth absorbs and re-radiates energy
In Earth’s Energy Budget, all of Earth is considered together

Air (Atmosphere)
Land (Lithosphere)
Ice (Cryosphere)
Ocean/Water (Hydrosphere)
Life (Biosphere)

10 of 25

What can you say about �emitted heat?

It comes in a range of

LONG wavelengths

11 of 25

Wavelengths of Energy �Emitted by the Sun and Earth

SHORT

LONG

12 of 25

Follow the Energy . . . .

13 of 25

Sun emits radiation

Earth intercepts

sunlight

Input = Sunlight

^{(short wave)}

Output= absorbed and re-radiated

^{(long wave)}

30% is reflected

14 of 25

Missing one more variable

A small part of the atmosphere is made of heat-trapping gases.
These gases absorb long wave radiation.
They are called greenhouse gases.

Examples:

Water Vapor (H₂O), Carbon Dioxide (CO₂)

15 of 25

15

16 of 25

Not all gases have �the same behavior

Some gases are greenhouse gases.

Most of the gases in the atmosphere do

NOT absorb long wave radiation.

17 of 25

Follow the Energy

18 of 25

Sun emits radiation

Earth intercepts

sunlight

Input = Sunlight

^{(short wave)}

Output= absorbed and re-radiated,

^{(long wave)}

heat trapped by greenhouse gases

30% is reflected

19 of 25

Only a little over half of the absorbed energy is re-radiated.

What happens to the other energy?

20 of 25

It remains absorbed by the Earth and causes a change in temperature

What if there wasn’t an atmosphere?

21 of 25

Concept Map Additions

Long wave radiation
Short wave radiation

Write 2 paragraphs describing what happens to the flow of energy into the Earth system.

22 of 25

Optional Slides

23 of 25

Thus far, the discussion has represented the average of Earth. Clouds and gases are very important in the energy budget. This slide shows that different types of clouds – cirrus and cumulus clouds – have a different impact on how much energy reaches the Earth’s surface.

The thickness of the line represents the amount of energy. Yellow is the solar radiation. Red is the emitted heat.

Thin cirrus clouds permit sunlight to pass through them, while blocking a significant amount of the heat radiating (long wave infrared) from the surface. Thick cumulus clouds reflect most sunlight, and block the majority of heat radiating from the surface. Compare the red arrows coming out of the clouds. In general, more cirrus means warming and more cumulus clouds mean cooling.

Image above: The Earth’s energy balance refers to the amount of energy received from the sun (yellow arrows) minus the energy reflected and emitted from the Earth (red arrows). Clouds play an important role in regulating this balance. Thin cirrus clouds permit sunlight to pass through them, while blocking a significant amount of the heat radiating from the surface. Thick cumulus clouds reflect most sunlight, and block the majority of heat radiating from the surface. Credit: NASA�http://www.nasa.gov/centers/goddard/news/topstory/2005/earth_energy.html

24 of 25

http://www.nasa.gov/centers/goddard/news/topstory/2005/earth_energy.html

25 of 25

Follow the Energy

VIDEO Energy Budget in Equilibrium �