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Directorate: Curriculum FET

SUBJECT and GRADE GEOGRAPHY – GRADE 12

TERM 1 Week 1 lesson 1

TOPIC MID-LATITUDE CYCLONES

AIMS OF LESSON To strengthen your knowledge, understanding and interpretation of mid-latitude cyclones and its

impact on Western Cape.

RESOURCES Paper based resources Digital resources

• Lesson on page 2

• Learner task on page 3-7

• Textbook: Mid-latitude

cyclones

https://www.youtube.com/watch?v=3kP-abSp-Q0&t=95s

https://www.youtube.com/watch?v=B_UBlkUKTMQ&t=87s

https://www.youtube.com/watch?v=RuzhMfYqldU&t=42s

INTRODUCTION You should know from previous grades/current grade/previous lessons

• Grade 10: Frontal rainfall

• Grade 11 Global air circulation - Westerlies.

CONCEPTS AND SKILLS You must know: • General characteristics of mid-latitude cyclones.

• Areas where mid-latitude cyclones are found

• Conditions needed for their formation

• Stages of development and related weather conditions

• Weather patterns associated with cold, warm and

occluded fronts

• Impact of mid-latitude cyclones

• Reading and interpreting satellite images and synoptic

weather maps

You must be able to:

• apply knowledge and

concepts on various

geographic sources.

• read and interpret graphs,

diagram synoptic weather

maps and satellite images.

• answer data response questions.

• write a paragraph.

ACTIVITIES/ASSESSMENT • Activity to the lesson is on page 3

• Additional activities in your textbook

CONSOLIDATION You must study these topics by asking key Geographic questions such as: What and where is it?

What does it look like? How does it differ? Why does it differ? How the impact can be managed

VALUES Awareness of our rainfall; sustainable use of water; and flooding..

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MID-LATITUDE CYCLONES

What does it look like? Where are mid-latitude cyclones found? What are cold and warm fronts?

Moves from west to east

WARM FRONT Air behind front warm. Warm air moves over the cooler air.

COLD FRONT Air behind front cold. Ridges underneath the warm air and lifts it.

What weather changes occur when a

cold front moves over an area?

What are the impacts?

Positive Negative

• Drop in Temperature

• Wind changes from NW to SW

• Increase in air pressure

• Increase in cloud cover

• Rainfall occurs

Must also know reasons for weather changes

• Brings rain fills dams

• Increases yield

• Water table rises

• Snow tourist attraction

• Sustains natural vegetation and animals

• Snow damages crops

• Flooding

• Stock losses

• Costly repairs

• Erosion

• Cold conditions -vegetation damage

How does a mid-latitude cyclone develop? (Development stages)

LEARNER TASK 1 Add the following labels to the diagram of the mid-latitude cyclone.

• Isobars of 1 008 and 1004 hPa

• Low pressure (L)

• Warm front

• Cold front

• Colour warm sector red

• Colour cold sector blue

• Clockwise circulation (with arrows)

2 The questions are based on the diagram below

2.1 Identify the type of front on the diagram (1x1) (1) 2.2 Draw a cross-section along the line A-B on the diagram. (4x1) (4) 2.3 Why is it a bad idea to visit one of the beaches at Cape Town? (2x2) (4) 2.4 Explain the changing weather conditions as the cold front passes over

Cape Town. (3x2) (6) 2.5 Write a paragraph of approximately EIGHT lines to describe the

human and environmental impacts of the mid latitude cyclone on agricultural activities. (4x2) (8)

[This paragraph-type question is unpacked on the following page]

UNPACKING OF PARAGRAPH-TYPE QUESTION 2.5

ANSWER

Impact on Human activities Positive: - Provides rain for agriculture

- Increases yield and income - Snow can be a tourist attraction

Negative: - Cold conditions and flooding can cause loss of life - Stock losses and damage to crops - Costly repairs and aid projects

Impact on the environment Positive: - Rain sustains natural vegetation and animals Negative: - Flooding causes erosion and loss of topsoil

- Eroded material slit up rivers and dams - Cold conditions can lead to vegetation damage (4x2) (8) Remember the

following when you attempt a paragraph-type question in Geography

3 The questions are based on the synoptic weather map

3.1 Give THREE reasons why the synoptic weather map represents winter. (3x2) (6) 3.2 Name the weather system moving across Southern Africa. (1x1) (1) 3.3 In which direction does this weather system move? (1x1) (1) 3.4 Why does this weather system move in the direction mentioned in 3.3? (2x1) (2) 3.5 Why can the front moving across the country be regarded as a cold front? (2x2) (4) 3.6 Describe the weather at the ship northwest of Cape Town. (5x1) (5) (Hint: Refer to temperature, dew point temperature, wind direction, wind speed and cloud cover)

QR CODES Scan the QR codes below to link you with the digital resources mentioned on page 1.

Characteristics of Warm and Cold fronts Development of mid-latitude cyclone mid-latitude cyclone

APPLICATION ON TOPOGRAPHIC MAPS AND ORTOPHOTO MAPS You must be able to apply your knowledge of the mid-latitude cyclone on op topographic and orthophoto maps. Answer the following two questions. In both cases hints are given to you in order to get to the answer.

1 Which of the residential areas, West End,Tuinsig oor Vleiview will receive more air pollution from the

industrial area:

(a) Before a cold front moves over Caledon? (b) After a cold front moves over Caledon?

Give a reason for your answer in (a) and (b)

HINT: Consider the wind direction before and after a cold front moves over an area.

2 Which of the runways , A or B at Port Elizabeth airport will be used:

(a) To take off BEFORE a cold front moves over the airport? (b) To land AFTER a cold front moved over the airport?

Give a reason for your answer in (a) and (b) HINT: Planes take off and land AGAINST the wind.