2.1 Diurnal Energy Budgets

Question 1

What is the difference between weather and climate

Answer 1

Climate is the average extended conditions of the atmosphere over an area over a long period of time.
Weather refers to the current conditions of the atmosphere

Question 2

What is a budget

Answer 2

• Refers the amount of energy entering a system, leaving the system and the transfer of energy within the system

Question 3

What is a microclimate

Answer 3

• Used to describe regional climates, such as those associated with large urban areas, coastal areas or mountainous regoins

Question 4

Describe the 6 components of a daytime energy budget

Answer 4

1. Incoming (shortwave) solar radiation (insolation)
2. Reflected radiation (albedo)
3. Surface absorption
4. Sensible heat transfer - conduction
5. Long-wave radiation
6. Latent heat (evaporation and condensation)

Question 5

Describe the 4 components of night-time energy budget

Answer 5

• Long-wave earth radiation
• Latent heat transfer (condensation)
• Absorbed energy returned to earth surface (from below the surface)
• Sensible heat transfer

Question 6

Explain incoming solar radiation

Answer 6

• Main energy input
• Affectred by latitude, season and cloud cover
• The less cloud cover/the higher the cloud, the more radiation reaches the surface

Question 7

Explain reflected solar radiation/albedo

Answer 7

• The proportion of enrgy reflected back to the atmosphere - albedo
• Albedo - varies with colour: light materials reflect more than dark materials
• Grass reflects around 20-30% of the radiation it recieves

Question 8

Explain serface and sub-surface absorption

Answer 8

• Energy that reaches the earth’s surface has the potential to heat it
• If the surface can conduct the heat to layers below it will stay cool, if it is concentrated at the surface it warms up
• The heat transferred to the soil and bedrock during the day mey bel released back to the surface at night

Question 9

Explain sensible heat transfer

Answer 9

• The movement of parcels of air
• For example air that is warmed may rise and be replaced by cooler air (convection)
• At night cold air can move into areas reducing temperatures/warm air parcels may increase temperatures

Question 10

Long-wave radiation

Answer 10

• Refers to the radiation from the earth into the atmosphere
• Net long-wave radiation balance = the difference between two flows of LWR from the atmosphere and from the earth
• During a clear day, there is much more LWR going out than coming back in = net loss of energy from the surface e.g. at night in deserts

Question 11

Explain latent heat transfer

Answer 11

• When liquid water is turned into water vapour energy is used up
• When liquid water becomes ice heat is released
• THERFORE WHEN WATER IS EVAPORATED INTO WATER VAPOUR, THE TEMPERATUER OF THE SURROUNDINGS GOES DOWN

Question 13

Latent heat transfer: absorbed energy returns to earth

Answer 13

• The insolation recieved by the earth will be reradiated as long-wave radiation
• Some of this will be absorbed by water vapour and other greenhouse gases, thereby raising the temperature

Question 14

Explain temperature changes close to the surface

Answer 14

• During the day the ground heats up due to SWR, conduction (contact) and convection
• Air recieves more energy than it emits, therefore is warmed
• Air close to the ground is also warmed through conduction
• Air speed is lower due to friction against surface therefore has more time to be heated