2.2 Global Energy Budgets

Question 1

Disproportional Heating of the earth

Answer 1

Differential Heating of the earth due to;
- Insolation levels; equator receives more overhead insolation year round; shorter days in winter at poles

• Angle of insolation; more direct heating at equator vs polar90 degrees at equator - therefore concentrates heating on a smaller area
• Albedo; increased reflection at poles = less absorption

This all leads to net surplus of energy at the low latitudes & net deficit in the polar regions

Question 2

Heat Redistribution

Answer 2

Due to this differential heating the earth redistributes its heat in several ways;

Atmospheric circulation; cells - 80% of heat redistribution
- surface trade winds
- Jet streams

Ocean Currents
- surface ocean currents
- deep ocean currents

Question 3

Jets Streams

Answer 3

What are they?
- Fast moving high altitude narrow bands of wind
- 250km/h
- responsible for rapid transfer of heat energy
- blow from east to west (meandering - rossby wave)

How do they form?
- when warm air meets cool air
- leads to a difference in air pressure
- higher pressure difference - faster the jet stream

Rossby Waves
- meandering motion of jet streams
- due to differential heating topography

Small Scale breezes
- differential temps of land and sea due to different SHCs
- convection winds

Variation over space & time
- most heat in winter due to large temp difference
- come lower over more land
- doesn’t effect the equator at all

Question 4

Trade Winds

Answer 4

Caused by
- pressure gradient difference at the boundaries of different cells
- low pressure at equatorial - high at subtropical - low at temperate
- pressure differences drive them and air moves from high to low pressure
- these pressure differences are caused by differential heating between equator and poles

These winds blow southeast in northern hemisphere and northern east in the southern as they are deflected right by the Coriolis effect

Question 5

Surface Gyres

Answer 5

• dynamic transfer of heat
• driven by winds
• circular and clockwise
• warm currents move to the poles and cold currents move to the equator
• can effect winds temperature above

Question 6

Example of cold surface gyre

Answer 6

Benguela Current
- cold ocean current
- transfers cold water from the south Atlantic up past the coast of south Africa towards the equator
- driven by the south-east trade winds
- leads to cooler climate - helps formation of Namid Desert

Question 7

Example of warm ocean gyre

Answer 7

Gulf Stream
- warm ocean current
- transfer warm energy from the equator to Northern Europe
- driven by the northeastern trade winds
- leads to mild winters in Northern Europe; 5 degrees london vs -10 in moscow winter

Question 8

Deep Ocean Currents

Answer 8

Great Ocean Conveyer Belt
- driven by gyres
- 4km below surface
- very slow transfer of energy - consistent - moderate climate

Question 9

What causes seasonal variations in pressure belts, winds & temperature?

Answer 9

Latitude - thermal equator shift
Land vs Sea - Specific Heat Capacity change 4200j/kg vs 800 j/kg
Ocean Currents - warm or cool winds (sensible)