topic: climatology: consolidation learner note...

GAUTENG DEPARTMENT OF EDUCATION SENIOR SECONDARY INTERVENTION PROGRAMME

GEOGRAPHY GRADE 12 SESSION 9 LEARNER NOTES

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TOPIC: CLIMATOLOGY: CONSOLIDATION

Learner Note: The climate chapter is dealt with in this session. This is usually split over two questions in the final exam in section A and combined with Geomorphology. For this exercise we will just focus on climate

SECTION A: TYPICAL EXAM QUESTIONS

The questions below come from a variety of past papers, textbooks and other resources.

They cover the main topics in the Climate chapter.

QUESTION 1: Global circulation / changes in energy balance 20 minutes 34 marks

1.1. Use the following sketch to answer the questions that follow.

1.1.1. The 2 features labelled A and B represent a high pressure and a low pressure cell.

Compare the air movement in these 2 features in table form. (6 x 2 = 12)

B

E

C

D

A



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1.1.2. There are 3 forces at work between the high pressure and the low pressure cells. These forces are indicated by the arrows C, D and E. Identify these three forces. (3 x 2 = 6)

1.1.3. Describe how forces C, D and E will influence the wind respectively. (3 x 2 = 6)

1.1.4. In which hemisphere are the pressure cells? (1 x 2 = 2)

1.1.5. Motivate you answer in question 1.1.4 with climatic evidence. (2 x 2 = 4)

1.1.6. The high pressure cell forms part of a global pressure belt. Identify the pressure belt that the high pressure forms part of. (1 x 2 = 2)

1.1.7. The low pressure cell is moving eastwards. Identify the global wind belt which pushes the low pressure eastwards. (1 x 2 = 2) [34]

QUESTION 2: Cyclones 40 minutes 66 marks

2.1. Read the weather report on the next page and answer the questions below.

2.1.1. Identify the approaching low pressure system that will lead to the weather

changes described in the report. (1 x 2 = 2)

2.1.2. Explain why nice clear skies and cool temperatures are predicted for the first part of this report (Tuesday and Wednesday) (2 x 2 = 4)

2.1.3. Account for the predicted changes in the weather form Thursday onward. Refer to the following: cloud cover, winds, temperature and precipitation (4 x 2 = 8)

2.1.4. List the stages in the cyclogenesis of these types of cyclones in chronological order. (3 x 2 = 6)

2.1.5. Draw a cross section along the line labelled L on the satellite image to illustrate the air masses, air movement, weather features, clouds and precipitation that occur in this area. (5 x 2 = 10)

HINTS:

Hint 1 – Read the questions very carefully. Underline or high light the action words and make

sure you understand the question, and answer what is asked.

Hint 2 – Use full sentences and good language in your answer, but do not use words that are

too difficult. Number correctly and make sure your answer book looks neat.



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L



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2.2. Use the map and weather report, and maps below page to answer the questions that follow.



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2.2.1. Where did this hurricane originate? (1 x 2 = 2)

2.2.2. What circumstance is required for hurricanes to develop? (3 x 2 = 6)

2.2.3. In what stage of development is hurricane Ike on the satellite image? (1 x 2 = 2)

2.2.4. Motivate you answer in question 2.2.3 with evidence from the satellite image. (1 x 2 = 2)

2.2.5. Explain what a storm surge is. (2 x 2 = 4)

2.2.6. Why must people in the low lying areas near the coast evacuate their houses and move to higher lying land? (2 x 2 = 4)

2.2.7. Why do you think do people ignore the weather warnings? (2 x 2 = 4)

2.2.8. Explain how hurricanes are named with Ike as an example. (2 x 2 = 4)

2.2.9. Global warming leads to changing climatic patterns. Explain what global warming is. (2 x 2 = 4)

2.2.10. Why would global warming lead to increased hurricane numbers, intensity and areas influenced by tropical cyclones. (2 x 2 = 4)

[66]

QUESTION 3: Weather over South Africa 20 minutes 34 marks

3.1. Use the sketch below to answer the following questions:



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3.1.1. Explain what a temperature inversion is. (1 x 2 = 2)

3.1.2. What causes the temperature inversion in these sketches? (2 x 2 = 4)

3.1.3. Identify the seasons illustrated in sketch A and B respectively. (2 x 2 = 4)

3.1.4. Describe the weather that will be experienced over the central plateau at A and account for these weather conditions. (6 x 2 = 12)

3.1.5. Describe the weather that will be experienced over the central plateau at B and account for these weather conditions. (6 x 2 = 12) [34]

QUESTION 4: Valley conditions 19 minutes 32 marks

4.1. Refer to figure 4 below showing a valley along the foothills of the

KwaZulu-Natal Drakensberg.

a) Identify wind Y as a Katabatic or an Anabatic wind. (2 x 2 = 4)

b) Does the figure represent day or night time? (1 x 2 = 2)

c) Give one reason for your answer to Question 4.1. (b) (1 x 2 = 2)

d) Briefly explain how wind Y develops. (2 x 2 = 4)



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4.2. Refer to the figure below that represents summer and winter conditions in a valley. X and Y represent different angles at which the sun’s rays strike the earth during these seasons.

4.2.1. In which hemisphere is this valley situated? Provide a reason for your answer. (2 x 2 = 4)

4.2.2. Which seasons do angles X and Y represent respectively? Provide a brief explanation of each case. (4 x 2 = 8)

4.2.3. Z represents a wind that develops during a particular time of day only.

a) Identify Z as a Katabatic or Anabatic wind. (1 x 2 = 2)

b) How does this wind develop? (3 x 2 = 6)

[32]

Summer and winter conditions in a valley

HINTS

Hint 1 – Keep the mark allocation in mind. There must at least one fact for each set of double

marks. Do not give long paragraph answers if you are not asked to do so.

Hint 2 – If a paragraph is asked and you give it as points or a bulleted list, you will be

penalised with at least 50% of the marks.



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WORD MEANING

Account to answer for - explain the cause of - so as to explain why

Analyse separate, examine and interpret critically

Annotate to add explanatory notes to a sketch, map or drawing

Argue put forward reasons in support of or against a proposition

Classify to divide into groups or types so that things with similar characteristics are in the same group - to arrange according to type or sort

Comment write generally about

Compare to point out or show both similarities or differences

Contrast stress the differences, dissimilarities, or unlikeness of things, qualities, events or problems

Define give the concise and clear meaning

Demonstrate to show or make clear - to illustrate and explain - to prove by reasoning and evidence - can give examples

Describe list the main characteristics of something - give an account of

Discuss examine by means of argument, presenting both sides and reaching a conclusion

Evaluate to make an appraisal or express an opinion concerning the value - to define, analyse and discuss

Explain to make clear, interpret and spell out the material you present

Give to state facts without discussions

Identify give the essential characteristics of - to name

Interpret to give an explanation of - to give the meaning of

Justify prove or give reasons for decisions or conclusions, using logical argument

List write an itemised series of concise statements

Mention refer to relevant points

Name to state something - give, identify or mention

Outline give a summary, using main points and leaving out minor details

Predict to say what you think will happen - to foretell - to say in advance

Provide to state facts without discussions

State to present information plainly without discussion

Suggest to propose an explanation or solution

Show to make clear - to point out - to explain

SECTION B: ADDITIONAL CONTENT NOTES



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SECTION C: HOMEWORK

Questions have been adapted from the gr.12 SBA tasks and cycle tests for 2010.

QUESTION 1: Urban Climates 5 minutes 10 marks

1. Refer to the figure illustrating a ‘heat island’ on the next page before answering the

questions that follow. Various options are provided as possible answers to the

questions. Choose the correct answer and write only the letter A to D next to the

question number.

1.1 The lines drawn on the map representing temperatures are called . . .

A Isohyets

B Isobars

C Isotherms

D Isolines

1.2 The temperature recorded at Uxbridge is . . .

A 6ºC

B 8ºC

C 5ºC

D 10ºC

1.3 The temperature range between Croydon and Edgeware is . . .

A 7ºC

B 5ºC

C 1ºC

D 0ºC

1.4 The steepest temperature gradient is recorded between the city centre (A) and …

A Dagenham

B Croydon

C Edgeware

D Uxbridge

1.5 The greatest effect of the heat island is experienced at . . .

A Epping Forest

B Central London

C Weybridge

D Edgeware (5 x 2) (10)



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QUESTION 2: Urban heat islands 25 minutes 40 marks

2. Refer to the figure below before answering the following questions.

2.1 Define the term ‘heat dome’. (1 x 2) (2)

2.2 Identify two sources of pollution within the city centre. (2 x 2) (4)

2.3 Is a heat dome better developed in winter or summer? (1 x 2) (2)

2.4 Account for your answer in 2.3 (2 x 2) (4)

2.5. Account for the irregular shape of the heat island. (1 x 2) (2)

2.6 What effect does the River Thames have on the mean annual temperature

of London? (1 x 2) (2)

2.7. Explain why the river has an effect on the temperatures of London. (2 x 2) (4)

2.8 Temperature in an urban environment is higher compared to the

temperature in rural areas. Discuss this statement in a paragraph

(no longer than 12 lines) by providing reasons for this phenomenon. (6 x 2) (12)

2.9. Humidity and precipitation in cities are different in rural areas.

a. Describe how the humidity in cities differs from rural areas. (1 x 2) (2)

b. How does the precipitation differ in cities from rural areas? (1 x 2) (2)

c. Account for these differences. (2 x 2) (4)



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QUESTION 3: Mid-latitude Cyclones 35 minutes 50 marks

3.1.1. Mid-latitude cyclones develop

a. in summer

b. in winter

c. all year round

d. autumn

3.1.2. Frontal rain occur most often in SA

a. in summer

b. in winter

c. all year round

d. in spring and autumn

3.1.3. Mid-latitude cyclones mostly pass over SA in

a. in summer

b. in winter

c. all year round


3.1.4. Berg winds occur most often in

a. in summer

b. in winter

c. all year round


3.1.5. Berg winds occur ahead of

a. tropical cyclones

b. warm fronts

c. anticyclones

d. cold fronts (5 x 2 = 10)

Use the map on the following page to answer the following questions:

3.2. Does this map illustrate winter or summer conditions? Motivate your answer. (2 x 2 = 4)

3.3. Describe the weather at Durban and Cape Town respectively by

completing the table for Cape Town and Durban. (16)

Weather Element Durban Cape Town

Weather

Temperature

Dew Point temperature

Cloud cover

Wind speed

Wind directions

Humidity

Air Pressure



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3.4. Why does the weather at Cape Town and Durban differ so much? (2)

3.5. How will the weather at Durban change in the next few days? (4)

3.6.1. How many mid latitude cyclones are visible on the map? (1)

3.6.2. Which one is the oldest cyclone? (1)

3.5.3. In which direction are the cyclones moving and why? (2)

3.6.4. Where did these cyclones originate? (1)

3.6.5. In what stage are the cyclones? (1)

3.7. Identify the 3 anti-cyclones on the map. (3)

3.8. Draw cross section from Cape Town to Durban to illustrate the weather

features between the 2 places. (5)

See Synoptic weather map of Southern Africa on next page.



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QUESTION 1

1.1.1. (6 x 2 = 12)

A High Pressure B Low Pressure

Air sinks / descends in a high pressure cell Air rises / ascends in a low pressure cell

Air moves clockwise around the HP in the Northern hemisphere

Air move anti-clockwise around a LP in the Northern hemisphere

Air moves away from an HP Air moves towards a LP

1.1.2. C: Pressure gradient

D: Coriolis force

E: Friction (3 x 2 = 6)

1.1.3. C: Pressure gradient: causes wind to move from a HP to and LP – the bigger the pressure difference the faster the winds will blow.

D: Coriolis force: deflects winds from their original direction to the right in the Northern hemisphere and to the left in the Southern hemisphere.

E: Friction: slows down winds near the surface of the earth (3 x 2 = 6)

1.1.4. Northern hemisphere (1 x 2 = 2)

1.1.5. Air moves clockwise around the HP in the Northern hemisphere

Air move anti-clockwise around a LP in the Northern hemisphere (2 x 2 = 4)

1.1.6. Sub-tropical High Pressure Belt (1 x 2 = 2)

1.1.7. Westerly winds (1 x 2 = 2)

[34]

QUESTION 2

2.1.1. Mid-Latitude cyclones (1 x 2 = 2)

2.1.2. The conditions are associated with the

warm sector of the mid-latitude cyclone

and the Kalahari HP over the interior in winter. (2 x 2 = 4)

2.1.3. Cloud cover: will change to overcast as the cold front approach

and cumulonimbus clouds form

Winds: winds become gale forces strength and change from Northerly to North Westerly as the pressure gradient near the centre

of the mid-latitude cyclone increases and the winds back around the

low pressure.

Temperature: the cool temperatures will drop to cold and move

from the Cape to the centre of the country as the cold front passes

over SA with the cold air behind it.

Precipitation: the clear conditions will change to showers as the frontal rain moves over the Cape with the cold front. Underlined parts are worth the marks (4 x 2 = 8)

SECTION D: SOLUTIONS AND HINTS TO SECTION A



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2.1.4. 1. Polar front stage / wave stage

2. Mature stage / warm sector stage

3. Occlusion stage / dissipating stage (3 x 2) (6)

2.1.5. [Any five of the six on the sketch] (5 x 2 = 10)

2.2.1. Over the warm water of the Gulf of Mexico outside 24ºN (1 x 2 = 2)

2.2.2. Water temperatures over 27ºC

Large scale evaporation from the warm water

Massive convection

Coriolis force

Intense low pressure cell [Any three] (3 x 2 = 6)

2.2.3. Mature (1 x 2 = 2)

2.2.4. The eye of the cyclone is visible (1 x 2 = 2)

2.2.5. A storm surge is the bulge of seawater that forms under the

intense LP in the centre of the cyclone and causes flooding of

coastal areas by seawater and dangerous waves. (2 x 2 = 4)

2.2.6. The storm causes the most damage near to the cost due to the fast

winds, the storm surge and the rain.

The coastal areas will be flooded by the storm surge and rain

The fastest winds hit the coast and then the winds start slowing

[Any 2] (2 x 2 = 4)

warm sector

Cold Sector



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2.2.7. They live in a hurricane zone and get warned regularly, but have

survived most of the smaller cyclones - complacent

They want to try and safeguard their houses, because looting takes

place when the houses are left unoccupied, and get damaged.

They do not have transport or money to evacuate

They are irresponsible [Any three] (2 x 2 = 4)

2.2.8. Hurricanes are named alphabetically with a person’s name

starting with an A for the first hurricane of the season.

Ike is the ninth hurricane of the season as I is the ninth letter of

the alphabet. [Any three] (2 x 2 = 4)

2.2.9. Global warming is the heating of the surface of the earth, i.e. the

atmosphere, oceans and land due to increased greenhouse

gases in the atmosphere that trap more heat and release less

heat into space. (2 x 2 = 4)

2.2.10. Global warming will increase the amount of evaporation and

moisture in the atmosphere and will cause larger areas in the

oceans to reach temperatures over 27 ºC. The warmer, moister

atmosphere will allow the hurricanes to become larger, more intense

and to last longer. More hurricanes will occur in one season

[Any three] (2 x 2 = 4)

[66]

QUESTION 3

3.1.1. A temperature inversion is an increase of temperature with an increase of attitude – a negative temperature lapse rate. (1 x 2 = 2) 3.1.2. Sinking air in the Kalahari HP heat up at D.A.L.R. and become warmer than the air from the sea which cools down at D.A.L.R. as it rises. The sinking air is warmer than the rising air underneath it.

[Any two] (2 x 2 = 4) 3.1.3. A: Winter B: Summer (2 x 2 = 4) 3.1.4. In A when it is winter the sinking air of the Kalahari High Pressure cell will heat up and become drier as it sinks. This will form an inversion below the escarpment which will not allow any moist air from over the oceans to enter the central plateau. This will lead to cool, dry, clear conditions over the interior, with frost occurring during the night as the dry air reaches dew point

temperature under 0ºC Three conditions with explanation for each] (6 x 2 = 12) 3.1.5. In summer (B) the inversion layer shifts south and moves upward with the other wind belts. Hot, moist conditions lead to convection rain. The longer warmer summer days cause convection over the interior which forms low pressure cells and drags in moist air from the Indian Ocean High pressure over the central plateau. This leads to orographic rain

along the escarpment and convection rain over the plateau. (6 x 2 = 12) [34]



The SSIP is supported by

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QUESTION 4: 4.1 a) Katabatic (2 x 2 = 4)

b) Night (1 x 2 = 2)

c) Cold night conditions cause the cold dense air to sink (1 x 2 = 2)

d) During cold nights the terrestrial radiation is lost quickly and the

surface cools down substantially.

The air in contact with the surface also cools down due to conduction,

and it becomes heavy and dense

The dense air sinks to the valley floor due to the shape of the valley

under the influence of gravity – this forms Katabatic winds [any 2](2 x 2 = 4)

4.2.1 In the southern hemisphere – the sun’s rays fall in from the north,

which means the equator must be north of the valley (2 x 2 = 4)

4.2.2. X: Summer

Sunlight more right above the valley which means the direct sunlight

is nearer to the valley

Y: Winter

Sunlight is falling in at an obtuse angle which means direct

sunlight is far from the valley (4 x 2 = 8)

4.2.3. a) Anabatic wind (1 x 2 = 2)

b) During the early morning and the day the hill tops are heated

before the rest of the valley.

This causes the air above the hills to heat up and rise which forms

low pressure cells.

The cool air in the valley bottom forms a HP.

Air moves from the HP to the LP up the slopes forming

anabatic winds. (3 x 2 = 6)

[30]

topic: climatology: consolidation learner note...

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