Atmosphere

Question 1

Ocean currents

Answer 1

-At the equator, water moves towards the west

• this is because of the coriolis force. This is the force that causes deflection in the winds and the Renault ant global winds which pushes water to the west by frictional drag
• this is aided by the fact that this area has the most intense heating and so the convection currents are set up within the water
• examples in the Atlantic Ocean are the north and south equation along currents
• when these currents reach land such as North America, they are deflected to the north and south
• thus transferring warmer water from the equator towards the poles.

-eg of these currents could be the Gulf Stream

• at around 30 degrees N+S of the equator, the currents are pulled eastwards again

As they are caught up in the next bands of global winds eg North Atlantic drift

• they are then deflected of the land again and some of the water is deflected back towards the water again
• thus completing a large circulation cell or gyre
• these circulate clockwise in the northern hemisphere and anticlockwise in the south

They bring warmer water to cooler areas and vies versa, thus helping balance the surplus and deficit due to global isolation

The colder currents are denser and so move out at lower levels. Warmer currents are nearer the surface

Question 2

3. What is atmospheric circulation

Answer 2

Ferrell 3 cell model

Question 3

Whats the ICTZ movement and impact on Western Africa

Answer 3

The ITCZ and its associated winds (TMand TC) move north and south with the overhead sun

The ictz is furthest south in December and migrates ro its most northerly position in June.

The tc and Tm air masses move with it in Dec/ Jan and the area its overhead will experience rainfall

As the ictz moves north, the tm winds are pulled further south, bringing wet weather to places which are south of the ictz

Places to the north of the ictz are still under the influence of the TC so are hot and dry

This means that towns recieve rain for a spell of the summer, known as seasonal rainfall- the rainy seasons get shorter the further north you go

Sometimes places will have 2 peaks of rainfall, this could be when the ICTZ moves over on its way north and south again

Question 4

Whats the ITCZ

Answer 4

Inter tropical convergence zone

Question 5

Describe the ITCZ

Answer 5

The thermal equator

Rainy water as air rises where 2 wind bands reach

tropical continental
It’s very hot and dry
Not as high levels of insolatiom
Dry as comes over land eg Sahara
Low humidity- 10-17%

Tropical marine
Warm and wet
War as area of greater insoaltion
-unstable air mass- changeable weather

Question 6

define ferrels 3 cell model -

Answer 6

atmospheric circulation

Question 7

what is atmospheric circualtion

Answer 7

-warm air rises at the equator. as it rises it cools and splits to the north and south and an area of low pressure is created at the surface

• as the air moves away from the equator it cools further and sinks back to the earth at 30 degrees north and south, creating an area of high pressure at the surface. thus completing the hadley cell

at 60 degrees north and south, warm air coming from the direction of the quator meets the cooler air coming from the poles

this warm air is forces up creating an area of low pressure at the surface. again, this air rises and splits. some heads back towards the equator, completing the ferrel cell

this is when air heads towards the poles and cools further and sinks back to eart, creating high pressure at the surface. this air then flows from high to low at the surface, thus completing the polar cell. this assists in the redistriubution of solar energy

this sets up t pattern of global surface winds as air flows from high to low pressure areas. because of the earths rotation, these winds are deflected to the right in the north hemisphere and to the left in the southern. this is known as the corrolis force. also known as trade winds

Question 8

Global insolation

Answer 8

It is warmer in the tropics and colder in the poles because the sun has more atmosphere to travel through to reach the poles. This means there is more chance of deflection because of dust, gasses etc. so less reaches the poles

• the angle of incidence is greater at the poles 120 Degrees compared to the equator 90 degrees
• because of earth, the suns energy is more concentrated at the equator. The same amount of energy is spread over a wider area at the poles
• at the equator we have more green vegetation which absorbs the suns energy, making it warmer. At the poles white ice and snow reflect energy through the albedo effect so its cooler
• due to the earths orbit around the sun, north the north and south hemisphere spend parts of the year tilted away from the sun so recieve less energy. The sun is always overhead in the tropics so they recieve energy all year round making it warmer.

Question 9

Global heat budget

Answer 9

Earth absorbs 50% of the solar energy is because 20% is reflected back from the albedo effect which is when surfaces reflect sunlight , and they get reflected back into the atmosphere by white clouds

Another 20% is absorbed by the atmosphere by having 3% absorbed by dark colours and a further 17% by atmospheric dust and vapours. 5% of solar energy is reflected back into the atmosphere by light surfaces on earth such as snow and ice

The earth then recieved 50% which is primarily absorbed by dark surfaces such as rainforests and deep oceans