9: Energy Balance

Question 1

Define Earth’s Energy Balance

Answer 1

The earth-atmosphere energy balance is the balance between incoming energy from the Sun and outgoing energy from the Earth. Energy released from the Sun is emitted as shortwave light and ultraviolet energy. When it reaches the Earth, some is reflected back to space by clouds, some is absorbed by the atmosphere, and some is absorbed at the Earth’s surface.

Question 2

Define Planetary Albedo

Answer 2

The fraction of the incoming solar energy scattered by Earth back to space

Question 3

Earth’s Energy Balance Calculation (Shortwave)

100 Units

Answer 3

8 Scattered by air
17 Reflected by clouds
6 Reflected by surface
=
31 Total lost to space

(69 Total gain of Shortwave))

19 absorbed by ozone water vapor & dust
4 absorbed by clouds
46 absorbed by surface

Question 4

Earth’s Energy Balance Calculation (Longwave)

100 Units

Answer 4

15 total Emit by surface
6 absorbed by GHGs
(9 Lost to space)

20 Emit by clouds to space
40 Emit by H2O, CO2 & O3

Total loss of Longwave = 69

Question 5

Earth’s Energy Balance Calculation (Land)

Answer 5

46 SW absorbed
15 LW emitted
=
Surplus of 31 units

Need to transfer to atmosphere
(sensible & latent heat)

Question 6

Earth’s Energy Balance Calculation (Atmosphere)

Answer 6

23 SW & 6 LW units
= 29 absorbed

60 units emitted

Deficit of 31 units

Need to transfer to land (latent & sensible heat)

Question 7

Sensible Heat

1) Define

Answer 7

1) The thermal energy whose transfer to or from a substance results in a change of temperature.
(heat you can feel)
Flux of energy which heats the atmosphere above the surface

Question 8

Latent Heat

1) Define
2) Give Two Examples
3) Why is it the most efficient mechanism for heat transfer?

Answer 8

1) Transfer of heat resulting in a change of phase, but no change in temperature
2) Water vapor
a) condensation in troposphere
b) evaporation at the surface
3) Due to large ocean mass of Earth

Question 9

Latent or Sensible Heat

1) Water Melting
2) Water Boiling
3) Water Freezing
4) Steam cooling or warming

Answer 9

1) Sensible heat
2) Latent heat
3) Neither
4) Neither

Question 10

1) Which is higher, latent or sensible heat?

2) Why?

Answer 10

1) Latent heat will always be higher

2) Due to Earth large ocean mass & so water is constantly evaporating

Question 11

Which will be dominated by latent heat or sensible heat?

1) Saturated Soil
2) Dry Soil
3) Vegetated Surface

Answer 11

1) Latent heat
2) Sensible heat
3) Latent heat due to transpiration, drives thermals & convection over the land

Question 12

Energy Balance - Net All-Wave Radiation
1) Define
2) Formula
3) Surface Energy Balance formula
What Denotes
4) Q*
5) Qh
6) Qle
7) Qg

Answer 12

1) Balance between incoming & outgoing long & short wave radiation
2) Q* = (SW low - SW high) + (LW low - LW high)
3) Q* = Qh + Qle + Qg
4) Net radiation
5) Sensible heat
6) Latent heat
7) Ground heat flux

Question 13

Ground Heat Flux

1) Depends on
2) In comparison with latent & sensible is it large or small

Answer 13

1) Thermal conductivity of the soil

2) Generally very small

Question 14

Define Austral Summer

Answer 14

Summer in the Southern Hemisphere; November-February

Question 15

Define Austral Winter

Answer 15

Winter in the Southern Hemisphere; June-September

Question 16

Energy Balance

During the austral summer, where is the peak radiation?

Answer 16

Southern hemisphere

Question 17

Energy Balance

During the austral winter, where is the peak radiation?

Answer 17

Northern hemisphere

Question 18

Net Radiation (Positive)

1) Where?
2) What colour/s depicts it?

Answer 18

1) At equator 40 N to 40 S
(always positive)
2) Yellow to red

Question 19

Net Radiation (Negative)

1) Where?
2) What does it mean if you are negative
3) What colour/s depicts it?

Answer 19

1) At the poles
2) Means you are losing more energy than you are gaining
3) Blue/green

Question 20

The oceans & atmosphere transfer heat & moisture from the equator to the poles
Why is it positive at the equator yet negative at the pole?

Answer 20

less and less energy from the sun, due to earth being a sphere,
-same ray of light heating the poles is heating a bigger area than the ray of light heating equator,
energy is more diffuse, so as we move down, we have a positive balance at the equator and a negative balance at the poles

Question 21

Where is the

1) Low incidence angle
2) High incidence angle

Answer 21

1) 40* N

2) At the equator

Question 22

Why do we get a Net Energy

1) Gain
2) Neutral
3) Loss

Answer 22

1) Solar input higher than infrared output
2) At the equator
3) Solar input lower than infrared output

Question 23

Global Atmospheric Circulation

When do Jet Streams occur?

Answer 23

When cells meet (Ferrel, Hadley, Polar), these are regions where you have a lot of air coming together

Question 24

Global Atmospheric Circulation
Name the three cells
&
Where are they located

Answer 24

Ferrel Cell 60 N & S
Hadley Cell 30 N & S
Polar Cell 60 - 70 N & S

Question 25

Which is slower, Atmospheric or Ocean Circulations

Answer 25

Ocean circulations are very slow in comparison

Question 26

Global Ocean Circulation
What colour denotes:
1) Warm water
2) Cold & Salty water

Answer 26

1) Red & Yellow

2) Blue

Question 27

Energy Imbalance

Is everywhere heated at the same time?

Answer 27

No, in one place it could be cold one year, than hot the next

Question 28

1) What Creates an Energy Imbalance?
&
2) What happens to it?

Answer 28

1) Adding CO2 to the atmosphere

2) Becomes excess heat, need which needs to be transferred around