Global Circulation Of The Atmosphere

Question 1

What are the 3 cells created in each hemisphere

Answer 1

• Hadley cell
• Ferrel cell
• Polar cell

Question 2

What is the troposphere

Answer 2

• the air that circulates within the cells
• it’s an area of the atmosphere from the Earths surface up to 10-15km high
• It’s the part of the atmosphere where the Earth’s weather takes place

Question 3

Where is the Hadley cell

Answer 3

• it’s the largest cell
• extends from the equator to between 30’ and 40’ north and south

Question 4

What happens in the Hadley cell

Answer 4

• Near the equator, the trade winds meet and warm air rises and forms thunderstorms
• from the top of these storms air flows towards higher latitudes where it becomes cooler and sinks over sub-tropical regions

Question 5

What are trade winds

Answer 5

• Winds that blow from the tropical regions towards the equator
• they usually travel from an easterly direction

Question 6

Where is the ferrel cell

Answer 6

• The middle cell, which generally occurs from the edge of the Hadley cell to between 60’ and 70’

Question 7

What happens in the ferrel cell

Answer 7

• It moves in the opposite direction from the Hadley and Polar cells, similar to a cog in a machine
• Air in this cell joins the sinking air of the Hadley cell and travels at low heights to mid-latitudes where it rises along the border with the cold air of the polar cell
• this accounts for frequently unsettled weather in UK
• Air then flows back towards the low latitudes, in the direction of the equator

Question 8

Where can you find the polar cell

Answer 8

It’s the smallest and weakest cell, which extends from the edge of the Ferrel cell to the poles at 90’

Question 9

What happens in the polar cell

Answer 9

• Air in this cell sinks over the highest latitudes, at the poles, and flows out towards the lower latitudes

Question 10

What is the Atmospheric air pressure

Answer 10

• The force exerted on the Earth’s surface by the weight of the air
• measured in millibars

Question 11

Where do you find low pressure in relation to the cells

Answer 11

• where the air in the Hadley cells rises at the Equator, low pressure is created

Question 12

Where do you find high pressure in relation to the cells

Answer 12

• where the Hadley and Ferrel cells meet at 30’ north and south of the Equator, air descends, creating high pressure

Question 13

What happens in areas of low pressure

Answer 13

• it occurs when atmospheric pressure is lower than that of the surrounding area
• associated with: high winds, warm, rising air
• so lots of rainfall due to rising air forming clouds
• temps are high as the clouds cover reflects solar radiation during the day and traps heat during the night

Question 14

What happens in areas of high pressure

Answer 14

• air cools and becomes denser = starts to fall towards ground = creating high pressure
• associated with: clear skies, dry (possibly hot), calm weather
• this is due to the heavy rain at the equator, meaning most of the moisture in the atmosphere is removed before the air reaches the sub-tropics