Greenhouse Effect and Earth's Energy Balance

Question 1

How is Earth’s atmosphere warmed and cooled?

Answer 1

Warming and cooling occur through the transfer of energy from the sun to the Earth, and back into the atmosphere. The energy that reaches the surface of the Earth will be absorbed and will result in warming.

Question 2

Four different mechanisms by which heat energy can be transferred in the atmosphere.

Answer 2

Radiation: sunlight warms the ground
Conduction: the warm ground heats the air
Convection: Cool dense air sinks downward and pushes warm air out of the way, carrying energy upward
Cooling

Question 3

What is latent heat? Know when latent heat is absorbed or released as water changes phases.

Answer 3

Liquid -> ice is released

Question 4

Why is latent heat important for the distribution of energy?

Answer 4

Latent heat supplies weather energy. As water condenses, latent heat from the water molecule is released into the air, heats the air, makes it lighter, and makes it rise fast. As the air rises, more air flows in and promotes storms.

Question 5

What are the most abundant gases in the Earth’s atmosphere?

Answer 5

N2 (78%)
O2 (21%)
Argon (0.9%)
Trade gases (water vapor, CO2, etc.)

Question 6

What are greenhouse gases and list the four major ones.

Answer 6

CO2
Methane
Water Vapor
Nitrous oxide

Question 7

What are the key natural and anthropogenic processes that contribute to greenhouse gases in the Earth’s atmosphere?

Answer 7

Agriculture, Industry use, Electricity & Heat, Transportation, Land Use Change

Sources:
- Burning fossil fuels
- wildfires

Sinks:
- Ocean
- Biosphere

Question 8

Why are O2 and N2 not greenhouse gases?

Answer 8

They are diatomic which means they vibrate moving closer and further apart rather than the stretching, bending, and rotation that map happen with non-diatomic molecules where the photon will be absorbed.

Question 9

What is the magnitude (size) of the natural greenhouse effect on Earth?

Answer 9

GHE = Surface Temp (Ts) - Effective Radiating Temp (Te)

288K - 255K = 33K

Question 10

GE equation

Answer 10

Ts = 2^(1/4) x 155K = 303.25K

Question 11

Why is the sky blue during the day and red at sunrise/sunset?

Answer 11

Rayleigh scattering, blue scatters more as sunlight travels through the atmosphere because it is smaller and the angle of the sun helps it.

Red gets transmitted more when the sun is low in the sky because it has to travel longer and through a denser environment before it reaches the viewer’s eye. Thus, other colors are easily scattered away before it reaches the viewer.