Download Atmosphere HW - Exercise 2 and model answer

HIGHER GEOGRAPHY – ATMOSPHERE HOMEWORK 2
QUESTIONS
1. Explain fully the ways in which the circulation cells in the atmosphere help to
redistribute energy.
2. For either the Pacific or Atlantic Ocean, explain fully how the ocean
currents operate to maintain the energy balance.
16 marks
GENERAL POINTS
Question 1
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The best way to structure this answer would be to move through the cells one by
one
Finish by making a stated about the general / overriding picture
Avoid talking too much about pressure and weather – the question does not ask
about this
At 60 degrees we have a zone of convergence, this forces air upwards
A lot of you are saying that heating forces air upwards – this is slightly incorrect, it
is about two air masses meeting forcing air up in the atmosphere
MODEL ANSWER:
Question 1
Warm air rises at the equator before travelling in the upper atmosphere to 30° N and S.
This air then cools and sinks. Some of the air returns over the surface to the equator to
form the Hadley Cell.
The remainder of the air travels N over the surface and converges at about 60° N and S
with cold air sinking at the Poles and flowing towards lower latitudes. The convergence
forces air to rise. Some of this air flows polewards in the upper atmosphere where it sinks
to form the Polar Cell.
The remainder of this air in the upper atmosphere travels south and sinks at 30° N and S
to form the Ferrel Cell.
It is in this way that warm air from the equator is distributed to higher (and cooler)
latitudes and cold air from the Poles is distributed to lower (and warmer) latitudes.
GENERAL POINTS:
Question 2
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Only discussing the North Atlantic
Not referring to named currents
Failing to mention / conclude the bigger picture
Including reasons for the direction of currents – not exactly what the question is
asking
Discussing weather implications in certain regions is not asked for
Focus should be on how energy is redistributed
MODEL ANSWER
Question 2
In the Northern Hemisphere a clockwise loop or gyre is formed. . Warm currents travel
westwards across the Atlantic at the equator. This movement is linked to the prevailing
westerlies (winds) which are found here.
Warm water from the Gulf of Mexico travels Northwards, e.g. The Gulf Stream linking
into the North Atlantic Drift. Cold water flows South to complete the gyre, e.g. The
Canaries current moves colder water from higher latitudes towards the equator.
In addition colder water also moves south from Polar latitudes, e.g. the Labrador Current.
This movement of warm and cold water helps to maintain the energy balance.
Mention should also be mentioned of currents in the Southern Hemisphere