Lecture 7

Question 1

What angle is solar radiation distributed on earth?

Answer 1

Oblique, resulting in same amount of radiative energy being distributed over a large surface area

Question 2

On average, incoming solar radiation is how much of the solar constant?

Answer 2

1/4

Question 3

Absorption

Answer 3

Radiative energy converted to other forms of energy by gases/particles in the atmosphere

Question 4

Reflection

Answer 4

Radiative energy is reflected back into space when hitting a surface

Light that bounces off at a surface at the same angle at which it strikes

Question 5

Scattering

Answer 5

Radiative energy is (at least partly redirected by air molecules and particles)

Deflects in all different directions

Question 6

Transmission

Answer 6

Radiative energy passes through the atmosphere

Question 7

Raleigh scattering

Answer 7

Air molecules
0.0001 to 0.001
Blue sky
Red sunsets

Question 8

Mie scattering

Answer 8

Aerosols
0.01 to 1.0
Browish smog

Question 9

Geometric scattering

Answer 9

Cloud droplets
10 to 100
White clouds

Question 10

Clouds deflect with what type of scattering?

Answer 10

Geometric

Question 11

What wavelengths are scattered more efficiently?

Answer 11

Shorter wavelengths

Question 12

Raleigh scattered diffuse light appears what colour?

Answer 12

Blue

Question 13

The longer the path length of sunlight through the air the more…

Answer 13

Blue light is scattered

The sun and its immediate area appear red

Question 14

Albedo effect

Answer 14

Earths albedo is approx 30%

It’s the % of radiation returning from a surface compared to what it strikes (aka ratio between reflected radiation to incoming radiation

E.g. Fresh snow = 75-95%

Question 15

Modes of thermal energy transfer:

Answer 15

Conduction: through contact
Convection: gases + fluids
Radiation: works also in a vacuum

Question 16

Energy transfer in the troposphere

Answer 16

Air in lower atmosphere - heated from ground upwards
Sunlight warms ground and air above through conduction, convection infrared radiation
Further warming - during condensation as latent heat is given to air inside the cloud

Question 17

Greenhouse gas effect

Answer 17

GHG’s are atmospheric gases which absorb thermal radiation emitted by the earths surface.
The blanketing effect leads to an increase in surface temperatures

Question 18

Which gas is the main temperature controller on earth?

Answer 18

Co2

Question 19

What is responsible for most of the GHG warming?

Answer 19

Water vapour, but it’s atmospheric abundance is not changing directly as a consequence of human activities

Question 20

Important GHGs influenced by human activities:

Answer 20

CO2 (most important and 2nd largest after water vapour) 
Methane CH4
Nitrous oxide N2O 
Chloro-fluorocarbons (CFCs) 
Ozone (O3)

Question 21

What is insolation?

Answer 21

Incoming solar radiation