The Climate System

Question 1

Effects of differential heating of the

Earth

Answer 1

• Energy surplus at the equator and
deficit at the poles leads to heat
transfers
• Convection – the dominant process
for transferring heat upwards from
the Earth’s surface
• Mass balance dictates that as some
air masses rise some must also fall –
hence the atmosphere is continually
turning
• This overturning occurs in the
troposphere

Question 2

What are jet streams?

Answer 2

• Fast-moving bands of air embedded in Rossby waves caused by sharp temperature differences (speeds up to 140 kms-1)

Question 3

What is subtropical westerly jet stream?

Answer 3

– Poleward boundary of the tropical Hadley cell
– Just below tropopause
– In winter it divides around the Tibetan Plateau

Question 4

What is polar front jet stream?

Answer 4

• Associated with the warm and cold fronts of temperate-latitude depressions
  – Considerable day-to-day variation

Question 5

What leads to heat transfers?

Answer 5

Energy surplus at the equator and deficit at

the poles leads to heat transfers.

Question 6

The large-scale circulation of the atmosphere is organised into what?

Answer 6

Cells.

Question 7

Where do jet streams form?

Answer 7

Jet streams form at the boundaries of the cells and play a major role in storm development.
Jet streams form into standing waves that affect the positions of major air masses.

Question 8

What does the term climatic system refer to?

Answer 8

An interactive system consisting of 5 major components: atmosphere, hydrosphere, cryosphere, land surface and biosphere.

Question 9

What is the present day atmosphere makeup?

Answer 9

78.1% nitrogen
20.9% oxygen
0.035% carbon dioxide
Surface pressure of 1 atmosphere

Question 10

What would the atmosphere be like if there was no life?

Answer 10

Like Venus-
1.9% nitrogen 
0% oxygen
98% CO2
Surface pressure of 70 atmospheres

Question 11

What is biomass?

Answer 11

The tissue formed in plant material as a result of solar radiation providing energy for photosynthesis- vegetation converts co2 into carbon and o2, the carbon is then combined with other elements to form the tissue.

Question 12

Where is most of the carbon on earth?

Answer 12

Contained in solid rocks such as limestone.

Question 13

What would happen if 0.03% of the buried carbon was returned to remain in the atmosphere?

Answer 13

The atmospheric conc would double, with devastating results for climate change.

Question 14

Atmospheric Co2 conc before and after industrial revolution…?

Answer 14

Before- 280 parts per million

383 ppm in 2007.

Question 15

Who is the largest consumer of energy globally?

Answer 15

China has overtaken the US.

However even after years of growth to 2035 China will still use less energy per person than countries in OECD.

Question 16

Statistics about those without energy?

Answer 16

1. 4 billion do not have access to electricity

2. 7 billion still use wood or other biomass to cook.

Question 17

Temperature rise over the past 30 years?

Risks!?

Answer 17

0.2 degrees per decade
Once temperature increases rises above 2 degrees up to 4 billion people could be experiencing water shortages.
This rise in temperature could see 40-60 million more people exposed to malaria in Africa.
Agriculture could cease to be viable in some locations, particularly in the tropics.
The melting of the Greenland ice sheet would contribute to sea level rise.

Question 18

What have the IPCC (2007) concluded needs to be achieved by 2050?

Answer 18

50% reduction in global Co2 levels compared with 2000 levels to limit the long term global average temperature rise to between 2.0 and 2.4%.

Question 19

What are the two major causes of the global wind circulation?

Answer 19

Inequalities in the distribution of solar radiation over the Earth’s surface, particularly in a north-south direction (more received at the equator), and the Earths rotation.

Question 20

What is global atmospheric circulation?

Answer 20

Global wind and ocean current circulation redistribute heat from equatorial regions where it is in surplus to polar regions where it is deficit

Question 21

What provides the energy for global atmospheric circulation?

Answer 21

Solar radiation received mainly at the equatorial East’s surface and reradiated back from the whole surface.

Question 22

What are the fundamental causes of seasonal differences in climate across the globe?

Answer 22

The approximately spherical shape of the Earth and the way the Earth’s axis of rotation is tilted at 23.44 degrees in relation to a perpendicular to the plane of the Earth’s orbit around the sun.
The greater the tilt of the axis the greater the difference between winter and summer.

Question 23

Why is there a sharp north-south temperature difference?

Answer 23

The same amount of solar radiation is spread over a larger area nearer the poles and also has a thicker layer of atmosphere to penetrate because of the angle at which the solar radiation is recieved.

Question 24

What causes the month by month changes in the amount of solar radiation reaching each part of the planet?

Answer 24

The tilt in the earth’s rotation.

Question 25

What creates the south-south temperature gradients that drive atmospheric/ocean circulation?

Answer 25

Solar radiation is mainly absorbed by the Earth’s surface in low latitude regions, while infrared long-wave radiation is continuously radiated to cold space from across the whole of the Earth’s surface.

Question 26

What is the three-cell circulation model?

Answer 26

Provides a view of global circulation

• Atmospheric circulation cells are located between the equator and 30 latitude, 30 latitude and 60 latitude, and 60 latitude an the pole
• Horse latitudes: areas of general subsidence in the zone between 20 and 35
• In each hemisphere the equator-ward flow from the horse latitudes forms the reliable *trade winds
• Prevailing Westerlies: the circulation between 30 and 60 latitude (N & S)
• Polar Easterlies: Air that moves equator ward from the poles produces PE in both hemispheres

Question 27

Hadley model (single-cell circulation model)

Answer 27

Proposed that the contrast in temperatures between the poles and the equator creates a large convection cell in both hemispheres
-Hadley cell: warm air rises @ equator until it reaches the tropopause where it spreads toward the poles.
(does not take into account earths rotation) (unequal heating in atmosphere of non-rotating earth)

*Suggested that the large temperature contrast between the poles and the equator creates a large convection cell in both the Northern and Southern Hemisphere

Question 28

Three- cell circulation model: Doldrums

Answer 28

Trade winds meet at the equator in a region with weak pressure gradient

Question 29

Three- cell circulation mode: Ferrel Cell

Answer 29

The westerly circulation of surface winds (prevailing westerlies) between 30-60 latitude

Question 30

Three- cell circulation mode: Polar Cell

Answer 30

Circulation at 60-90 within a polar cell produces polar easterlies; surface flows that move toward equator

Question 31

What are trade winds?

Answer 31

The equator ward-flowing easterly winds on the equatorial sides of the subtropical anticyclones.

Question 32

What is the intertropical convergence zone?

Answer 32

Trade winds meet in a trough of low pressure near the equator. This tough contains a convergence one near the surface known as the ITCZ.

Question 33

Air masses at the Intertropical Convergence Zone (ITCZ)

Answer 33

Meet and rise causing a trough of low pressure and heavy rainfall

Question 34

Monsoons are principally caused by

Answer 34

Seasonal differential heating/cooling of land and sea