Worked examples questions - Weather Hazards

 

(Source) 

Study the diagram above and state the two circulation cells that meet at latitudes of 30 degrees North and South of the Equator.         [2 marks]

State - express in clear terms 

So first of all look for the two command words. Actually look at the diagram, identify where the 30 degree latitude lines. Latitude lines are the ones that go horizontal. 

Then write down the two cells that meet at the 30 degree line of latitude. These are Hadley and Ferrell cells. Note that there are two answers for two marks. 

Too easy for you? How about this one?

Explain how global atmospheric circulation contributes towards distinctive weather and climate patterns.                                     [4 marks]

Explain - set out purposes or reasons

So, first of all you need to know something about the global atmospheric circulation - the Earth's atmosphere is constantly moving, transferring heat from one location to another via atmospheric circulation cells. each cell has distinctive cells.

You also need to know the difference between weather and climate. Weather is the state of the atmosphere over a small area and a short period of time (e.g. 1 hour) and climate is the state of the atmosphere over a large area and ta long period of time (e.g. 30 years).

Here are some bullet points that may help to create your answer, but I am not going to write the answer for you:

  • Warm rising air creates low air pressure
  • Cold sinking air creates high air pressure
  • Air blows from areas of high pressure to low pressure areas. 
  • Wind is affected by the Coriolis Effect (CE) - the spin of the Earth on its axis acts upon the movement of air flow. The CE deflects winds to the right in the Northern hemisphere and vice versa, wind is deflected to the left in the Southern hemisphere.
  • Different circulation cells cause different air pressure and surface winds cause different weather conditions due to their location
  • Remember that warm air rises and cold air sinks - look for the radiator to remind yourself 
  • Warmed air rises at the equator
  • The air cools and sinks (high pressure) at 30 degrees North or South of the Equator, this is the Hadley Cell.
  • Some of the cooled air moves towards the equator as a trade wind and the rest of the air goes towards the north or south pole as the Ferrel cell. 
  • The Polar Cell at 60 degrees north or south is where cold air meets warm air and it forms a polar front. Above this is a Polar Jet Stream that powers an unstable atmosphere. The Polar Cell has warm air sinking to form cooler air. 
  • The Polar Easterlies create dry, cold air conditions near the poles. 
  • The Trade Winds absorb moisture as they move from east to west producing precipitation when they blow over land, 
  • Do you remember the three types of rainfall?

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