Atmosphere

Question 1

Explain the physical and human factors leading to increased variations in the earths temperature.

Answer 1

PHYSICAL

1) sunspot activity = changes in solar radiation outputs raise and lower earths temperatures.
2) ORBITAL VARIATIONS= every 41,000 years there is a tilt in earths axis = increases insolation at the poles
3) VOLCANIC ERUPTIONS = dust shields incoming radiation = lowers earths temperature
4) methane levels = peat bog and termites

HUMAN CAUSES

1) increase in C02 from burning fossil fuels for industry and transport
2) CHOPPING DOWN RAINFOREST= deforestation and decomposing material releases c02
3) FARMING = methane levels increase through grazing.

Question 2

Explain fully the ways in which circulation cells and surface winds assist in helping to redistribute energy across the world.

Answer 2

HADLEY CELLS

1) direct heating at the equator = low pressure
2) air cools and sinks at the tropics = high pressure

POLAR CELLS

1) cold air sinks in polar zones = high pressure
2) air moves towards equator and is warmed by sea and land= rises at sub-tropics and returned back to the poles

FERREL CELLS

1) lies between Hadley and FERREL cells
2) warm air at tropics = transferred to higher latitudes
3) reduces DEFLICT at poles and SURPLUS at equator

CORIOLIS effect
1) deflects surface winds to right in northern hemisphere and left in Southern Hemisphere.

SURFACE WINDS
Tradewinds = energy from tropics to the equator
Westerlies = energy from tropics to poles

ROSSBY WAVES
Formed by westerly winds
Southward cold air = from lower latitudes
Northward warm air = higher latitudes

Question 3

Account for the variations in the Suns energy (polar and tropical)

Answer 3

TROPICAL

1) midday sun is directly overhead = Suns rays are more concentrated so higher energy is received
2) suns Ray’s have less atmosphere to pass through = less energy loss through absorption and reflection
3) tropical rainforest have dense vegetation and absorb radiation. = low albedo effect

POLAR

1) suns angles is much lower= Ray’s spread over larger area and therefore Sun is less intense
2) earths curvature means Ray’s have to travel further through atmosphere = 85% chance of more of reflection
3) polar regions have snow and ice which reflects more solar radiation= high albedo effect created
4) 6 months poles do not receive sums energy due to tilt and Earth orbit = DEFLICT OF ENERGY AT THE POLES

Question 4

Describe and explain the earths energy exchanges

Answer 4

1) 21% lost by highly reflective clouds
2) 5% reflected by atmospheric gasses and dust
3) 6% reflected by earths surface
4) 56% of energy reaches earths surface.
50% absorbed by Earth (land and vegetation)
6% reflected by glaciers, water and deserts

EXPLANATION: snow, ice and clouds reflect more of the Suns energy and have a relatively high albedo effect ( COOLING EFFECT)

Question 5

Describe the origin, nature and characteristics of tropical maritime and tropical continental

Answer 5

TROPICAL MARITIME

1) origin = SEA Atlantic Ocean on tropical latitudes
2) characteristics= warm, moist and unstable
3) Nature = associated with very hot, hot and humid weather

TROPICAL CONTINENTAL

1) originates = LAND over Sahara ( large land mass in tropics)
2) characteristics= stable, dry and warm
3) nature= associated with very warm and dry weather winter and summer = extremely hot

Question 6

Account for the patterns in Atlantic and Pacific Ocean.

Answer 6

1) ocean currents are surface movements of water
2) North Atlantic = circular and clockwise movements (GULF STREAM)
3) South Atlantic = circular and anti-clockwise routes (CANARIES CURRENT)
4) this is because atmospheric circulation cells produced prevailing winds which blow over he surface
5) ocean currents = dragged in same way As the direction in the prevailing winds
I.e clockwise = north hemisphere
Anti-clockwise = Southern Hemisphere
6) currents from poles to equator are cold water
7) currents from equator to poles = warm water

Question 7

Describe the role of ocean re-distribution of earths energy

Answer 7

1) equatorial waters = heated more than polar waters due to increased energy at the tropics
2) polar waters = colder and heavier and sink to ocean floor
3) POLAR CURRENTS (Labrador) = flows towards equator and displaces lighter and warmer water upwards
4) GULF STREAM= at the same time light and warm water rises and as surface currents and flow polewards.
5) cold polar water = travels to equator and warm Equatorial water = poles
6) CONC. Oceanic circulation transfers heat energy from surplus to DEFLICT.

Question 8

Describe and account for the variations in rainfall across Africa.

Answer 8

In January ITCZ = South Africa
Tropical airmass affects most of Africa = dry season and stable air mass + no RAIN
Tropical maritime = only affects coastal areas = heavy rainfall due to low pressure of ITCZ

IN JULY: ITCZ dominates Northern Africa
Tropical continental = limited to north Sahara and in drought years may extend further south (due to high pressure)
Tropical maritime = warm wet air over south Sahara = unusable air mass.
Brings heavy rains as the ITCZ passes = some places receive a twin peak of rainfall that year