GEOGRAPHY CLIMATE FINAL

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TABLE OF CONTENTS 1. INTRODUCTION 3 2. HOW TO USE THIS SELF STUDY GUIDE? 4 3. EXAMINATION STRUCTURE 5 4. EXAMINATION TIPS 6 5. REVISION: GRADE 10 AND 11 8 ACTIVITY 5.1: GRADE 11 REVISION 10 ACTIVITY 5.2: GRADE 11 REVISION 11 6. MID-LATITUDE CYCLONES 12 A. KEY CONCEPTS: MID-LATITUDE CYCLONES 13 B. NOTES/SUMMARIES ON MID-LATITUDE CYCLONES 14 ACTIVITY 6.1: MID-LATITUDE CYCLONE 20 ACTIVITY 6.2: MID-LATITUDE CYCLONE 22 ACTIVITY 6.3: MAP WORK APPLICATION 23 7. TROPICAL CYCLONES 24 A. KEY CONCEPTS: TROPICAL CYCLONES 25 B. NOTES/SUMMARIES ON TROPICAL CYCLONES 26 C. ACTIVITY 7.1: TROPICAL CYCLONES 32 ACTIVITY 7.2: TROPICAL CYCLONES 33 7.2 STUDY THE CASE STUDY OF TROPICAL CYCLONE ELOISE 33 WHICH HITS MOZAMBIQUE. ACTIVITY 7.3: TROPICAL CYCLONES 34 ACTIVITY 7.4: MAP WORK APPLICATION 35 8. SUB-TROPICAL ANTICYCLONES 37 A. KEY CONCEPTS: SUBTROPICAL ANTICYCLONES AND 38 ASSOCIATED WEATHER CONDITIONS B. NOTES/SUMMARIES ON SUB-TROPICAL CYCLONES 39 C. ACTIVITY 8.1: SUB-TROPICAL ANTICYCLONES 47 ACTIVITY 8.2: SUB-TROPICAL ANTICYCLONES 48 1

ACTIVITY 8.3: SUB-TROPICAL ANTICYCLONES 49 ACTIVITY 8.4: SUB-TROPICAL ANTICYCLONES 50 ACTIVITY 8.5: MAP WORK APPLICATION 51 9. VALLEY CLIMATE 52 A. KEY CONCEPTS: VALLEY CLIMATE 53 B. NOTES/SUMMARIES ON VALLEY CLIMATE 54 ACTIVITY 9.1: VALLEY CLIMATE 57 ACTIVITY 9.2: VALLEY CLIMATE 58 ACTIVITY 9.3: VALLEY CLIMATE 59 ACTIVITY 9.4: MAP APPLICATION 60 10. URBAN CLIMATE 61 A. KEY CONCEPTS 62 B. NOTES/SUMMARIES ON URBAN CLIMATE 63 C. ACTIVITY 10.1: URBAN CLIMATE 69 ACTIVITY 10.2: URBAN CLIMATE 70 ACTIVITY 10.3: URBAN CLIMATE 71 REFER TO FIGURE 10.3 SHOWING A POLLUTION DOME OVER A 71 SOUTH AFRICAN CITY. ACTIVITY 10.4: MAP WORK APPLICATION 72 11. POSSIBLE ANSWERS 73 12. ANNEXURE A: EXAMINATION ACTION VERBS 87 13. REFERENCES 89 14. ACKNOWLEDGEMENTS 90 2

1. INTRODUCTION The declaration of COVID-19 as a global pandemic by the World Health Organisation led to the disruption of effective teaching and learning in many schools in South Africa. The majority of learners in various grades spent less time in class due to the phased-in approach and rotational/ alternate attendance system that was implemented by various provinces. Consequently, the majority of schools were not able to complete all the relevant content designed for specific grades in accordance with the Curriculum and Assessment Policy Statements in most subjects. As part of mitigating against the impact of COVID-19 on the current Grade 12, the Department of Basic Education (DBE) worked in collaboration with subject specialists from various Provincial Education Departments (PEDs) developed this Self-Study Guide. The Study Guide covers those topics, skills and concepts that are located in Grade 12, that are critical to lay the foundation for Grade 12. The main aim is to close the pre-existing content gaps in order to strengthen the mastery of subject knowledge in Grade 12. More importantly, the Study Guide will engender the attitudes in the learners to learning independently while mastering the core cross-cutting concepts. 3

2. HOW TO USE THIS SELF STUDY GUIDE? This Self-Study Guide only covers the section on Climate and Weather of South Africa. The booklet is designed to explain concepts that seem to be challenging to learners in the Grade 12 Examinations. The first part focuses on the examination structure for Paper 1 and Paper 2, followed by explanation of the most common action verbs used in the question paper and how learners should manage their time. The second part focuses on the selected key concepts with their explanatory notes, followed by assessment activities designed from previous examination question papers. The guide also provides relevant answers and guide learners on how to use a mark allocation (on a question) in order to determine the extent of your response. Mapwork has been integrated in all the relevant sections to follow the new Examination structure. The guide should be used in conjunction with other resources such as DBE approved textbooks, 2021 Examination Guidelines and Geography CAPS document. 4

3. EXAMINATION STRUCTURE 3.1 PAPER 1 3.1.1 This is a 3-hour question paper which is written on a SEPARATE DAY from Paper 2. 3.1.2 The mark allocation for this paper is 150. 3.1.3 The question paper consists of two sections, namely SECTION A and SECTION B: SECTION A: Climate and Weather and Geomorphology (Theory) SECTION B: Geographical Skills, Techniques, Application and Interpretation and GIS (Map work) 3.1.4 SECTION A consists of TWO questions of 60 marks each. SECTION B consists of ONE question of 30 marks. 3.1.5 All the THREE questions are compulsory. 3.2 PAPER 2 3.2.1 This is a 3-hour question paper which is written on a SEPARATE DAY from Paper 1. 3.2.2 The mark allocation for this paper is 150. 3.2.3 The question paper consists of two sections, namely SECTION A and SECTION B: SECTION A: Settlement and Economic Geography of South Africa (Theory) SECTION B: Mapwork- Geographical Skills and Techniques (Map work) 3.2.4 SECTION A consists of TWO questions of 60 marks each. SECTION B consists of ONE question of 30 marks. 3.2.5 All the THREE questions are compulsory. 5

4. EXAMINATION TIPS TYPES OF QUESTIONS The types of questions in both Paper 1 and Paper 2 are as follows: 4.1 Short objective questions: ü Multiple-choice: • Know what each multiple-choice question is asking. • Evaluate each answer to the multiple-choice question. • Eliminate each answer that is clearly wrong. • Do not leave any question unanswered. ü Matching: • Know the definitions/explanations of concepts for each section as you will be required to pair each item with the correct terminology provided. • These questions assess recognition and recall of knowledge acquired. 4.2 Data response questions • With a data response question, you are required to interpret diagrams, maps, photos, tables, statistics, cartoons, etc. • Data response questions require knowledge, application analysis and evaluation. • Marks for data response questions range from 2-8 marks. 4.3 Paragraph-type questions Paragraph assess communication skills, knowledge and insight. These questions require critical and analytical thinking. In order to master these questions, learners should: • underline the main topic of the question, • underline the action words or question verbs, • underline the focus areas of the question (note that most paragraph questions might require two aspects or issues that must be discussed/ explained in two equal parts), • write in full sentences to explain answers, and • avoid repetition of facts. 6

An illustration of how to analyse a paragraph question statement: The cost of food will increase because the polluted water will be expensive to purify so that it could be used in agriculture. Farmers will have to buy more chemicals to purify the water. If not, they will have to buy purified water from other service providers at a costly price. This will have a negative impact on production costs in agriculture, leading to increased food prices. Furthermore, polluted water reduces soil fertility which could lead to crop failure. This could lead to food being imported from other countries at very expensive prices in order to prevent food insecurity in the country. Polluted water will be expensive to purify so as to generate hydro-electricity, thereby causing Eskom to inflate electricity prices. Increased production costs will increase electricity costs. Less production of electricity due to river pollution will increase demand and supply, making electricity costs expensive. (4 x 2) (8) 7

5. REVISION: GRADE 10 AND 11 HIGH- AND LOW-PRESSURE CELL (Grade 10) Importance of High- and Low-pressure Cells: The unequal heating of the atmosphere results in the development of high- and low- pressure cells. It is important that you know the characteristics of High- and Low- pressure cells High pressure cell Low pressure cell Cross section Plan view • Air subsides (decends) • Air ascends (rises) • Air diverges at the centre • Air converges at the centre • Clear/dry skies • Condesation takes place • No release of latent heat • Latent heat is released during • No cloud formation condensation • Oval shaped isobars • Clouds form and precipitation Characteristics • Air circulates in an occurs anticlockwise rotation • Circular shaped isobars • Isobar values increase • Air circulates in a clockwise towards the centre of the high rotation pressure • Also known as a cyclone • Also called an Anticyclones • Isobar values decrease towards • Forms: the centre of the low pressure - South Atlantic Anticyclone • Also called a Cyclone - South Indian Anticyclone • Forms: - Kalahari Anticyclone - Coastal low - Mid-Latitude cyclones - Tropical cyclones 8

WORLD PRESSURE BELTS (Grade 11) Importance of the Pressure belts: The development of High- and Low-pressure cells results in the development of the pressure belts at different latitudes because of pressure gradient and Coriolis force that have an impact on the global circulation of the atmosphere. Pressure belts Caracteristics of the Pressure belts Polar high at • Associated with cold, dense air which subsides over the poles. 90° N and S • Stable, clear and cold • conditions prevail • A region of low pressure associated with the convergence of two different air masses. Sub-polar • The air is forced to rise. Low at • This creates a low-pressure area. 60° N and S • Also called the polar front and this is where mid-latitude cyclones originate. • A region of high pressure associated with subsiding air Sub-tropical • The descending air is warm and dry. High at • Deserts form in these regions. 30 °N and S • Associated with clear skies and low rainfall. • A region of high pressure associated with subsiding air. • Associated with clear skies and low rainfall. • Also called the inter-tropical convergence zone (ITCZ) where Equatorial low maximum heating takes place. at 0° • Hot air rises creating a low-pressure area at the surface. • The rising air is moisture laden. • Associated with convergence thunderstorms and high rainfall. • Confluence of NE trade winds and SE trade winds at 5° North Source: https://www.40knots.net/what-are-the- trade-winds/ and South results in the development of Tropical cyclones. 9

ACTIVITY 5.1: GRADE 11 REVISION 5.1 Study FIGURE 5.1, the world map showing Global Air Circulation and identify the following features. [Source: https://www.internetgeography.net/topics/what-is-global-atmospheric-circulation/ 5.1.1 Name the pressure cell that develops at 90⁰ N and S. (1) 5.1.2 The surface wind which develops between the 30⁰ and 60⁰ North and South. (1) 5.1.3 The pressure belt that would dominates the 30⁰ North and South latitude. (1) 5.1.4 Identify the surface wind that will be experienced between the 90⁰ and 60⁰ North and South latitudes. (1) 5.1.5 What is another name for the 0⁰ latitude area? (1) 5.1.6 Name the pressure cell that develops at 60⁰ N and S. (1) 5.1.7 Identify the surface wind that will be experienced between the 30⁰ and 0⁰ North and South latitudes. (1) (7 x 1) (7) 10

ACTIVITY 5.2: GRADE 11 REVISION 5.2 Study FIGURE 5.2 and answer the questions that follow by choosing the appropriate word/phrase from the text box. [Source: http://geophile.net/Lessons/atmosphere/atm_circulation_05.html] High, Low, Warm, Cold, Diverge, Pressure Cells, Rise, Polar Easterlies, Converge 5.2.1 In the Polar Cell there is a … pressure. (1) 5.2.2 In the Polar Cell air sinks because it is … (1) 5.2.3 Winds in the Polar Cell … in the upper atmosphere. (1) 5.2.4 The winds in the Ferrel Cell … on the surface. (1) 5.2.5 Winds converge and … at the equator. (1) 5.2.6 The Hadley Cell is associated with … pressure. (1) 5.2.7 Air rises in the Hadley Cell because it is … (1) (7 x 1) (7) 11

6. MID-LATITUDE CYCLONES AREA OF DEVELOPMENT STRATEGIES TO MINIMISE THE IMPACT CONDITIONS FOR DEVELOPMENT IMPACT ON MID-LATITUDE CYCLONES HUMANS, ECONOMY CHARACTERISTICS AND ENVIRONMENT WEATHER PATTERNS SATELITE IMAGES STAGES AND SYNOPTIC WEATHER MAPS 12

A. KEY CONCEPTS: MID-LATITUDE CYCLONES Term Explanation A huge mass of air, extending for hundreds of kilometres, with similar Air mass temperature and humidity The anticlockwise change in wind direction that occurs as a mid-latitude Backing cyclone passes over. The leading edge of a cold air mass of a mid-latitude cyclone. Cold front An occlusion where the overtaking cold air is colder than the cold air ahead Cold front of it. The overtaking cold front lifts warm air off the ground. occlusion The mass of colder air behind the cold front in a mid-latitude cyclone. Cold sector The development and strengthening of a mid-latitude and Tropical cyclone. Cyclogenesis The boundary separating two air masses with different densities. Front The Inter Tropical Convergence Zone; an area where the tropical easterlies ITCZ converge. A band of very strong westerly winds high in the atmosphere (troposphere) Jet stream: which partly controls the development of mid-latitude cyclones. A large, low-pressure weather system made up of warm and cold fronts; Mid-latitude also called an extra-tropical cyclone, temperate depression or frontal cyclone depression. Occluded A front formed when a cold front overtakes and replaces a warm air mass. front The decaying stage in the development of a mid-latitude cyclone where the cold front to the rear catches up with the leading warm front, lifts the warm Occlusion air off the ground and meets the cold air ahead of the warm front. Zone separating the cold polar air (easterlies) and warm tropical air Polar front (westerlies). The shift of wind in a clockwise direction over time at a specific location, for Veering wind example from a southerly to south easterly. The leading edge of a warm air mass. Warm front An occlusion where the overtaking cold air is warmer than the cold air Warm front ahead of it. occlusion The warm air behind the warm front of a mid-latitude cyclone. Warm sector 13

B. NOTES/SUMMARIES ON MID-LATITUDE CYCLONES AREA OF DEVELOPMENT • Located in the middle or temperate latitudes • Between latitudes 30° - 60° north and south of the equator. • Forms at the polar front where warm westerlies and cold polar easterlies meet OTHER NAMES • Moderate Cyclone • Extratropical Cyclone • Temperate Cyclone [Source: https://lotusarise.com/temperate-cyclone-extratropical-cyclone-upsc/] • Frontal depression CHARACTERISTICS CONDITIONS NECESSARY FOR DEVELOPMENT • Extensive low-pressure in center of the system. • Clockwise movement of air in Mid-Latitude Cyclone in Southern • Cold polar air mass from cold polar easterlies and Hemisphere. warm tropical air from warm westerly winds, meet. • Presence of a cold front. • Cause an imbalance in energy distribution • Cold sector (Area of cold air behind cold front). because of difference in temperature. • Presence of a warm front. • Differences in wind patterns(direction) contribute to • Warm sector (Area of warm air behind warm front). resultant formation. • Isobar pattern is oval. • Moves from west to east because its driven by stronger westerly winds MORE PROMINENT IN WINTER OVER SOUTH • Affects the Western side of continents in the middle latitudes. AFRICA • Diameters are between 1 500 and 3 000km. The northward migration of the ITCZ and with it the • Travels at a speed of about 50 – 60 km per hour. migration of the high-pressure cells, results in the low- • Lifespan of system is between 4 and 14 days. pressure systems moving over Southern part of South • They usually occur in families (two or more). Africa. • Forms all year but better developed in winter from April to October in South Africa. 14

STAGES OF DEVELOPMENT OF A MID-LATITUDE CYCLONE 4. OCCLUDED STAGE FOUR STAGES 1. Initial stage 2. Development stage 3. Mature stage 4. Occluded stage • Warm sector continues to narrow. • Cold front overtakes the warm front cold air wedges in under warm air. • The warm air then becomes isolated from the ground. [Source: wcedonline.westerncape.gove.za] • This is called an occlusion. 1. INITIAL STAGE 2. DEVELOPMENT STAGE 3. MATURE STAGE •The low pressure intensifies. • The Polar front is stationary. • A wave develops in the polar •It moves into the westerly wind belt away from • Warm westerly and cold polar easterlies. front. the polar front. blow in opposite directions along the • A small mass of warm air • A well-developed cold and warm sector polar front. extends into the cold air and develops. • The different air masses do not have the rises. • Cold dense air moves faster and forces the light same density, temperature, and humidity. • This rising air cause a low humid less dense air in the warm sector to rise. • Therefore, they do not mix. pressure in the centre. • The cold sector becomes larger than the warm • Friction develops between the air sector as the cold air moves and lifts the warm masses. air. 15

TWO TYPES OF OCCLUSIONS: COLD FRONT OCCLUSION: WARM FRONT OCCLUSION: • Air ahead of the cold front is slightly warmer than the air • Air ahead of the cold front is colder than the air behind the behind the cold front. cold front. • This causes the warm air in front to be uplifted along the • This results in the air behind the cold front and the warm air in cold front. warm sector, rising over the cold air in the front. • Rising air cools, condensation takes place and forms • Rising air cools, condensation takes place and forms nimbostratus clouds. nimbostratus clouds. • This results in rain. • This results in rain. [Source: https://slidetodoc.com/air-masses-and-fronts-ii-brief-review-an/] [Source: https://slidetodoc.com/air-masses-and-fronts-ii-brief-review-an/] 16

THE APPEARANCE OF MID-LATITUDE CYCLONES ON SATELLITE IMAGES AND SYNOPTIC WEATHER MAPS COLD FRONT WARM FRONT SATELLITE IMAGE CROSS-SECTION SYNOPTIC WEATHER MAP TOP VIEW / PLAN VIEW [Source:Adapted from https://www.futurelearn.com/info/courses/learn- about-weather/0/steps/28922 17

ASSOCIATED WEATHER PATTERNS COLD FRONT WARM FRONT [Source: https://apollo.nvu.vsc.edu/classes/met130/notes/chapter11/cf_xsect.html] CYCLONE WEATHER COLD SECTOR COLD FRONT WARM SECTOR WARM FRONT APPROACHING Air pressure Increase slowly Sudden increase Remains steady Decrease stops Steady decrease Wind South Backing from west West Backing from north-west Northwest direction to south to west Wind speed Gusty, decrease Very strong to gale Decrease Strong Increase slowly slowly force Temperature Cold, around 5 °C Sudden decrease Warm to mild, Sudden rise Cool, around 8 °C around 12 °C Relative Rapid fall High during Steady and high High during precipitation Slow rise humidity precipitation Cloud cover Decreasing in Very thick and Low stratus clouds Low and thick High and thinner clouds succession to towering/vertical with clear patches in nimbostratus altostratus, cirrostratus cumulus cumulonimbus between and cirrus Precipitation Heavy and later Short period of Intermittent drizzle or Continuous rainfall – None soft, persistent heavy rain and hail stop steady and quite heavy showers Visibility Very good, but poor Poor, especially Often poor Decrease rapidly Good, but decreasing during showers during showers with nearing front and fog 18

REASONS FOR WEATHER CHANGES IN COLD FRONT CHANGE COLD FRONT REASON Temperature Decrease Cold air behind front has arrived. Wind “backs” becomes SW Clockwise rotation from air around the low pressure. Cloud cover Increases Warm air rises over the approaching cold air, cools and condenses. Cloud type Cumulonimbus Cold air forces the warm air to rise rapidly and condensation occurs to great heights. Pressure Decrease then increase Pressure at its lowest just before cold front then it rises as cold air arrives. Rainfall Heavy rainfall over small area Strong convection taking place and cumulonimbus clouds. IMPACT OF MID-LATITUDE CYCLONE ON HUMANS, ECONOMY AND ENVIRONMENT HUMANS ENVIRONMENT ECONOMY • Winter rainfall determined type of crops that are cultivated. • Winter rainfall that is necessary for • Production of POSITIVE • Rain replenish water in dams. winter crops. winter crops • Snow in mountains replenish water when it melts. • Production of winter crops results in benefits the GDP. food security. • Snow that falls is dangerous for people. • Snow that falls is dangerous for • Expensive for • Extreme cold can result in power cuts and disruption of livestock. farmers to protect human activities. • Extreme cold damage crops and crops and • Berg winds that develop in warm sector is hot and dry and livestock. livestock. can encourage the spread of veld fires. • Berg winds damage vegetation • Floods can • Gale force winds behind cold front results in stormy because of dry warm conditions. damage crops and NEGATIVE conditions over ocean and is a danger to ships. • Gale force winds damage crops. impact the • Heavy rain from cold front leads to poor visibility and traffic • Heavy rain cause floods which is economy negative. accidents. negative for crops and livestock. • Mountain passes may be closed if there is snow. STRATEGIES TO MINIMISE THE IMPACT OF MID-LATITUDE CYCLONES • Monitoring the development of Mid-Latitude cyclones. • Keep livestock in barns to protect them against the cold . • Early warning systems for people to be prepared. • Plant winter crops that can resist cold. • Evacuate low lying areas to protect it against floods. • People should stay indoors for protection against the cold, wind, and rain. 19

ACTIVITY 6.1: MID-LATITUDE CYCLONE 6.1 Various options are provided as possible answers to the following questions based on the cross-section of the mid-latitude cyclone in FIGURE 6.1. Choose the answer and write down only the letter (A–D) next to the question numbers (6.1.1 to 1.1.8), e.g. 6.1.9 D. [Source: DBE Paper 1 November 2019] 6.1.1 The general direction of movement of the mid-latitude cyclone in the Southern Hemisphere is … -wards. A north B west C east D south 6.1.2 Identify cloud A that is associated with the warm front. A Stratus B Cumulus C Nimbostratus D Cumulonimbus 6.1.3 The area at B is referred to as the … A warm sector. B cold sector. C polar front. D apex. 20

6.1.4 The type of cloud at C is … A stratus. B cirrus. C cumulonimbus. D nimbostratus. 6.1.5 The gradient at D can be described as … A steep. B gentle. C weak. D vertical. 6.1.6 The … front is found at D. A polar. B cold. C occlusion. D warm. 6.1.7 The more active and faster moving front is the … front. A polar B cold C warm D moisture 6.1.8 The type of rainfall at E is/are … A light showers. B frontal rain. C orographic rain. D convectional rain. (8 x 1) (8) 21

ACTIVITY 6.2: MID-LATITUDE CYCLONE 6.2 Refer to FIGURE 6.2 which shows a mid-latitude cyclone. [Source: http://lukemweather.blogspot.com/2011/01/something-little-different- look-at.html] 6.2.1 Provide ONE point of evidence visible in FIGURE 6.2 to substantiate that the mid-latitude cyclone shown is in the mature stage of development. (1 x 1) (1) 6.2.2 Which hemisphere is depicted in FIGURE 6.2? (1 x 1) (1) 6.2.3 Draw a transverse profile from E to F in FIGURE 6.2 and indicate the following: (a) An arrow indicating the direction of movement of the front. (b) A label for the cloud type depicted. (c) The area of cold air. (d) The area of warm air. (4 x 1) (4) 6.2.4 Account for the likelihood (chance) that expected rainfall at location A in FIGURE 6.2 will be gentle. (2 x 2) (4) 6.2.5 An outdoor music festival is planned at location D in FIGURE 6.2 in the next 24 hours. Recommend the rescheduling of the event by providing TWO climatological reasons as to how the music festival could be affected by the expected changes in weather that may occur. (2 x 2) (4) 22

ACTIVITY 6.3: MAP WORK APPLICATION 6.3 Study the extract of the 3419 AC HERMANUS topographic map and the simplified map of South Africa showing an approaching mid-latitude cyclone. Source: Glenn Samaai PowerPoint presentation [Source: Extract from 3419 AC HERMANUS] 6.3.1 Predict the direction of movement of the mid-latitude cyclone located South-west of Hermanus. (1 x 1) (1) 6.3.2 In which general direction will fishermen launch their boats from the New Harbour? (1 x 1) (1) 6.3.3 Explain how the approaching mid-latitude cyclone will impact the launching of the fishing boats at Hermanus harbour? (2 x 2) (4) 23

7. TROPICAL CYCLONES KEY CONCEPTS AREA OF STRATEGIES TO DEVELOPMENT MINIMISE THE IMPACT CHARACTERISTICS IMPACT ON HUMANS, TROPICAL ECONOMY AND CYCLONES ENVIRONMENT CONDITIONS FOR DEVELOPMENT WEATHER PATTERNS SATELITE IMAGES AND SYNOPTIC STAGES WEATHER MAPS 24

A. KEY CONCEPTS: TROPICAL CYCLONES Term Explanation Adiabatic Occurs when air descends and compresses, resulting in very little heating precipitation. Is the rate at which the temperature of an air parcel changes in response to the compression or expansion associated with elevation Adiabatic lapse change, under the assumption that the process is adiabatic, i.e., no rate heat exchange occurs between the given air parcel and its surroundings. A force caused by the rotation of the earth which results in the deflection of the winds and ocean currents. Deflection is to the right Coriolis force in the northern and to the left in the southern hemisphere. Dissipate Is to break up or disappear or weakening The calm area at the centre of a tropical cyclone Eye The walls of cumulonimbus cloud which surround the eye of a Eyewall tropical cyclone. The heat or energy that is absorbed or released during a phase Latent heat change of a substance. It could either be from a gas to a liquid or liquid to solid. The term used to describe the arrival of the eye of a tropical cyclone Make landfall over the coast. An abnormal rise of water along the coast associated with a low- Storm surge pressure system as a tropical cyclone. A powerful, rotating storm system, around a low-pressure cell which Tropical develops over a warm ocean between the tropics. the eye moves Cyclone: over land. Tropical A tropical cyclone is classified as making a landfall when the centre cyclone landfall of the storm moves across the coast, in strong tropical cyclones. A mass of spinning air that attracts more air to its centre. Vortex It is a weak tornado that forms at sea in association with the storm Water spout clouds of a tropical cyclone. 25

B. NOTES/SUMMARIES ON TROPICAL CYCLONES Grade 11 Revision: Refer to pressure belts as indicated in the revision section on the Mid-latitude cyclones. (Page 9) The diagram below shows the areas where tropical cyclones are found. [Source: https://www.mapsofworld.com/hurricane/distribution/spatialdistribution.html] AREA OF DEVELOPMENT • Develop between latitudes 30° N and 30°S. • Result of the confluence of the Tropical easterlies at 5°N - 30°N and 5°S to 30° S of the equator. • Do not develop on the equator and 5°N and 5°S because there is a weak Coriolis force that can deflect the wind. OTHER NAMES: Named differently in different regions: • Hurricane: Golf of Mexico • Typhoon: Japan and eastern China • Tropical cyclones: Africa and Australia SOURCE OF ENERGY: • Latent heat is released as warm, moist tropical air condenses. 26

CONDITIONS NECESSARY AND REASONS FOR DEVELOPMENT • 5° N and S of equator - Weak Coriolis force at equator. • Ocean must be warmer than 26.5 °C – Warm water has a high evaporation rate to feed the LP system. • Develop only over the tropical oceans – there is less friction over a smooth surface. • Hot moist air - creates unstable air that continue to rise. • Unstable air results in condensation - condensation release latent heat into the atmosphere which provides more energy. • Surface air convergence - Air is forced to rise when it converges at a low- pressure system. • Upper air divergence - More moist air is drawn into the system at the surface as the air diverge in the upper air. • Intense low-pressure cell enhanced by the tropical jet stream in the upper air – because of stronger surface convergence, convection and upper air divergence. • Needs Coriolis forced to cause spiraling winds - deflection of air results in clockwise circulation in Southern Hemisphere. CHARACTERISTICS OF A TROPICAL CYCLONE • Intense low-pressure system, below 1000 hPa. • Late summers and autumns over warm tropical oceans. • Clockwise movement of air in Tropical Cyclone in the Southern Hemisphere. • Steep pressure gradient increases the wind speed. • Winds up to 300km/h. • Move from west to east within the tropical easterlies. • Eye develop in the centre of low pressure. • High Cumulonimbus clouds forms the eye wall. • Heavy rainfall, hail, storm surges and hurricane winds. • Receive alphabetic names. • Affect the east coast of continents. • Develop only over oceans, dies out over land because of friction and lack of moisture. 27

STAGES OF DEVELOPMENT OF TROPICAL CYCLONES INITIAL STAGE DEVELOPMENT STAGE MATURE STAGE DECAYING STAGE • Convergence of air towards a • Intensity of storm increases as • Storm reach its maximum • Air cools down low pressure (LP). air continue to coverge and intensity. when entering the • Creates a vortex. rise in LP centre. • Pressure drops to about 950 temperate latitudes. • Air pressure about 1002hPa. • Divergence takes place in hPa. • Cooler air flows into • Wind speed up to 60 km/h. upper atmosphere. • Wind speed exceed 180 km/h. the cyclone • Air pressure drops below • Fully developed eye. increasing the 990hPa. • Eye is clear, cloudless due to pressure. • Wind speed increases to adiabatic warming of • When moving about 120 km/h. subsiding air. inland, supply of • Eye forms in centre of LP. • Vortex well developed. moisture is cut of [Source: • Huge cumulonumbus clouds • Up to 600 km in diameter. and surface friction https://www.legacyias.com/low- slows it down. forms the eyewall around the • Torrential rain, thunder and pressure-area-may-intensify-into- cyclonic-storm/ eye. lighting. • Huge cumulonumbus clouds forms around the eye and swirls to form a vortex. 28

PRESENTATION OF TROPICAL CYCLONES ON SATELLITE IMAGES AND SYNOPTIC WEATHER MAPS SATELLITE IMAGE SYNOPTIC WEATHER MAP [Source: http://earthobservatory.nasa.gov] [Source: https://www.researchgate.net/figure/Surface-synoptic-weather-map] ACTIVE QUADRANT • Strongest area of a Tropical Cyclone. • When winds rotating around the storm center coincide with the winds moving the cyclone system from east to west. • Forward left-hand quadrant in Southern hemisphere. 29

ASSOCIATED WEATHER PATTERNS CROSS-SECTION TOP VIEW WEATHER ELEMENTS [Source: Adapted from https://wps.prenhall.com/wps/media/objects/616/631756/tropcycl /pages/structurehtml rom Unknown resources] 1 2 3 4 5 Rises but still Air pressure Dropping Drops < 950hPa Normalises low Rises to ± Drops due 28°C due to Temperature ±27°C to cloud ± 27°C Normilises adiabatic cover heating Hurricane strength Calm in the Hurricane Slow down and Wind speed Fast winds – eye, no strength wind normilises Strongest in wind the cyclone Torrential Clear sky, Softer rain that clears Rainfall Light rain Torrential rain rain no rain up 30

IMPACT ON HUMANS, ECONOMY AND ENVIRONMENT HUMANS ENVIRONMENT ECONOMY • Torrential rain results in the risk of flooding. • Strong winds cause storm surges • Airports are closed. • Strong winds damage and shatter windows and rip off which can cause rapid rise in • Damage harbor facilities. roofs. sea-levels. • Businesses are closed. • Storm surges cause damage to the coastal areas. • Floods and salt water destroy • No trading is possible. • Damage infrastructure. Roads and bridges washed away. agricultural crops. • Costly to repair damages. • Loss and damage of homes. • Flooding and rise in river levels • Job losses, unemployment • Damaged water pipes result in lack of fresh water. because of rain can cause • High medical expenses. • Wind and water damage power lines. mudslides and landslides. • Costly insurance claims • Deaths and injuries of people and animals because of • Destroy ecosystems and (business and personal). wind, floods and storm surges. biodiversity. • Put a strain on local civic • Starvation because of lack of food. • Livestock drowns. services. • Outbreak of deseases e.g. cholera, typhoid etc. • Lack of clean water. • Limits export. • Major financial strain on families. • Threatening of food security. • Increases imports (food and • Subsistence farmers lose everything. • Damaged sewerage pipes result other commodities). • Swell of waves is dangerous for fisherman/humans. in pollution. STRATEGIES TO MINIMISE THE IMPACT OF TROPICAL CYCLONES • Monitoring the development of Tropical cyclones. • Keep livestock in barns to protect them against the wind and rain. • Satellite tracking can monitor the development and path. • People should stay indoors to protect themselves against flying • Satellite censors to collect details e.g. rainfall rates. debris, wind, and rain. • Advanced weather predictions and warnings. • Upgrade technology in LEDC countries. • Early warning and communication for people to prepare. • Good medical care will reduce outbreak of deseases. • Evacuate low lying areas to protect people against floods. • Good emergency services that is well-equipped. • Ensure that infrastructure is of good quality. • Local civic/emergency services should be well-prepared to assist. 31

C. ACTIVITY 7.1: TROPICAL CYCLONES 7.1 Refer to FIGURE 7.1 showing a cross-section of a tropical cyclone. Choose the correct word(s) from those given in brackets to make the statements TRUE. Write only the word(s) next to the question numbers (7.1.1 to 7.1.7) in the ANSWER BOOK. [Source: https://www.tulane.edu/~sanelson/Natural_Disasters/tropical_cyclones.htm 7.1.1 Cloud A is a (cumulus/cumulonimbus) cloud. 7.1.2 The updrafts at B are caused by (convection/advection) currents. 7.1.3 Area C is named the (eye/eye wall). 7.1.4 The atmospheric condition experienced at C is (stable/unstable) 7.1.5 D indicates an area of (divergence/convergence). 7.1.6 E will experience (light rain/thunderstorms). 7.1.7 Ocean F is likely (warm/cold). (7 x 1) (7) 32

ACTIVITY 7.2: TROPICAL CYCLONES 7.2 Study the Case Study of Tropical Cyclone Eloise which hits Mozambique. Tropical Cyclone Eloise made landfall early morning on 23 January near Mozambique's city of Beira, causing widespread damage and flooding on a long swathe of coastline and impacting an area still recovering from Cyclone Idai Neighbouring southern African nations are also being hit by torrential rainfall and flooding from Eloise, which weakened to a tropical storm after landfall. Tropical Cyclone Eloise made landfall at Category 1 strength, with winds of 140 km/h and [Source: http://earthobservatory.nasa.gov] gusts up to 160 km/h, According to Mozambique’s National Institute of Meteorology. Beira received 250 mm of rain in 24 hours, and other areas that were flooded ahead of Eloise’s landfall also received additional heavy rains. Eloise impacted Madagascar before crossing the Mozambican Channel, killing at least one person. RSMC La Réunion warned of heavy rains in parts of Zimbabwe, South Africa, Botswana, says WMO regional centre La Réunion. The South African Weather Service issued top-level Red Alerts as floods swept through the northern part of the country, including the famed Kruger National Park. Eloise poses a serious threat to the coast of Mozambique, and is dangerous cyclone, “according to RSMC La Reunion. “High winds, heavy rainfall and dangerous sea conditions are to be expected. There is a major risk of coastal flooding. [Source:https://public.wmo.int/en/media/news/tropical-cyclone-eloise-hits-mozambique] 7.2.1 How many tropical cyclones have occurred before tropical cyclone Eloise in this season? (1 x 1) (1) 7.2.2 Give evidence from the satellite photo that Eloise is a tropical cyclone in the Southern Hemisphere. (1 x 2) (2) 7.2.3 In what stage of development is this weather system? (1 x 1) (1) 7.2.4 Give a description of the characteristics of the storm in this stage. (2 x 2) (4) 7.2.5 In a paragraph of approximately EIGHT lines describe the possible impact that Eloise will have on Mozambique, Zimbabwe and South Africa. (4 x 2) (8) 33

ACTIVITY 7.3: TROPICAL CYCLONES 7.3 FIGURE 7.3 is based on a case study of a tropical cyclone that recently affected Southern Africa. FIGURE 2.3 Tropical cyclone Idai has quickly strengthened into an intense tropical cyclone and has been fluctuating (changing) in intensity over the past 48 hours. An intense tropical cyclone is equivalent to a category 3 hurricane. Idai is slowly moving in a westerly direction towards Mozambique with wind speeds exceeding 170 km/h closer to the eye. It is expected to reach the coastal area near Beira, Mozambique's fourth largest city with 530 000 residents, [Adapted from turntable.kagiso.10] before midnight on Thursday. 7.3.1 Refer to the article. With what can you compare this intense tropical cyclone? (1 x 1) (1) 7.3.2 Name ONE condition that was necessary for the formation of tropical cyclone Idai. (1 x 1) (1) 7.3.3 Refer to the image and determine the expected wind speed with which tropical cyclone Idai will reach the coast of Mozambique. (1 x 1) (1) 7.3.4 Why will the wind speed decrease as you move further from the eyewall? (1 x 2) (2) 7.3.5 Explain how the dangerous semi-circle of tropical cyclone Idai originated (developed). (1 x 2) (1) 7.3.6 In a paragraph of approximately EIGHT lines, suggest the negative impact that high wind speeds will have on the coastal areas of Mozambique. (4 x 2) (8) 34

ACTIVITY 7.4: MAP WORK APPLICATION 7.4 Refer to the satellite image of tropical cyclone Idai and topographic map of 2732 CD KULENI Greater St. Lucia) below. Tropical Cyclone Idai had devastating impact on the St Lucia Estuary Tropical cyclones will affect South Africa during January and February. Only Tropical Cyclones moving into the Mozambique channel influence South Africa’s weather. Shocking images of devastation were recorded on 10 March 2019 when a the bridge over the Mzinene river washed away by the cyclone, which restricted access from of KwaMduku to rescue the residence on the flooded Cloete farm. 35

7.4.1 From which direction will tropical Cyclone Idai approach the Greater St. Lucia area? (1 x 1) (1) 7.4.2 Give evidence from the topographic map that the bridge at C on the topographic map, was prone to flooding. (2 x 2) (4) 7.4.3 A leisure boat was anchored at Tonn’s Point (A). Explain what caused it to be blown to point B. (1 x 2) (2) 36

8. SUB-TROPICAL ANTICYCLONES LOCATION / CONDITIONS AREA OF NECESSARY FOR MOISTURE DEVELOPMENT FRONT DEVELOPMENT LINE THUNDERSTORM TRAVELING DISTURBANCES SUB-TROPICAL CHARACTERISTICS ANTI-CYCLONES COASTAL LOW BERG SYNOPTIC WEATHER WINDS MAPS and ASSOCIATED ANTICYCLONES WEATHER PATTERNS OVER SA 37

A. KEY CONCEPTS: SUBTROPICAL ANTICYCLONES AND ASSOCIATED WEATHER CONDITIONS Term Explanation Adiabatic heating Heating which occurs when the air is compressed. Anticyclones A large high-pressure cell of stable subsiding air. A local wind that blows down the escarpment from the plateau to the Berg wind coast, bringing hot, dry weather. A localised low-pressure system that brings changeable weather to Coastal low: a coastal region. Cut-off low A low-pressure cell which has become completely displaced over pressure system: the land and moves independently of any air around it. Inversion layer: A layer of air where temperature increases with increasing altitude. Kalahari High: A large high-pressure cell over South Africa’s interior; it is responsible for clear skies and dry conditions in winter. Summer storms that occur when a trough of low pressure develops Line thunderstorm over the interior between the thermal low and coastal low. A boundary over the interior where warm, moist air blowing from the Moisture front: north-east (Indian Ocean) meets cool, dry air from the south-west (Atlantic Ocean). An extension of a high-pressure cell when the isobars extend along Ridge: the east -west axis. This happens when the south Atlantic high sometimes extends behind a passing cold front in winter or around the southern tip of South Africa in summer. South Atlantic A large high-pressure cell over the Atlantic Ocean; it sometimes High-Pressure: pushes cold fronts inland. South Indian High A large high-pressure cell over the Indian Ocean; it is responsible Pressure: for rain in the eastern half of South Africa. Sub-tropical High-pressure cells of the general circulation centred at about 30ᵒ anticyclones North and South. Thermal low- A thermal low-pressure that develops over the central interior of pressure: Southern Africa in the summer. Occurs between two low pressure cells or an extension of a low- Trough: pressure cell. Subsiding air Is sinking air. 38

B. NOTES/SUMMARIES ON SUB-TROPICAL CYCLONES CLIMATE AND WEATHER REVISION (GRADE 10 AND 11) 1. Oceans: South Africa is surrounded by the THE 3 MAIN FACTORS THAT INFLUENCE SOUTH AFRICA’S ocean and the weather is influenced by ocean WEATHER currents. - The warm Mozambique/Agulhas current CROSS SECTION over the Indian Ocean. Onshore winds bringing warm air that has high moisture content. - The cold Benguela current over the Atlantic Ocean flows next to the west coast and onshore winds bring cold/cool air that has low moisture content. 2. Relief: The interior part of South Africa is a high–lying plateau; temperatures in South Africa are generally lower because the higher the altitude the lower the temperature). TOP VIEW 3. South Africa’s latitudinal position in the sub- tropics results in the weather being affected by the subtropical high-pressure cells, called anticyclones. The anticyclones are: § South Atlantic Anticyclone [Source: www.learnxtra.co.za] § South Indian Anticyclone § Kalahari Anticyclone 39

SUB-TROPICAL ANTICYCLONES CONDITIONS NECESSARY FOR THE DEVELOPMENT OF SUBTROPICAL ANTICYCLONES • Descending air from tropical and mid-latitude cells at 30° North and South of the equator. http://www.ecn.ac.uk/what-we-do/education/tutorials-weather-climate/climate/oceancurrents.png CHARACTERISTICS OF ANTICYCLONES • Anticlockwise circulation. • Air diverges at the centre • Dry descending air results in stable atmospheric conditions and intensifies high pressure system. • Clear skies with sunshine. • Winds blow outwards in an anti- clockwise direction in the southern hemisphere. • Adiabatic warming of decending air in the anticyclone. [Source: Unknown] • Responsible for the semi-arid conditions over South Africa. • Affect climate of South Africa because of the location at 30° South. • More prominent in winter over South Africa because of the northward Migration of the ITCZ. 40

THREE ANTICYCLONES THAT HAVE AN IMPACT ON SOUTH AFRICA’S CLIMATE SOUTH ATLANTIC ANTICYCLONE KALAHARI ANTICYCLONE SOUTH INDIAN ANTICYCLONE • Location – Namibian coast. Location - above the central plateau. • Location - east coast of South • Semi-permanent and semi-stationary. Summer: Africa. • Changes are seasonal, linked to • Temperature is warmer above plateau. • Semi-permanent and semi- seasonal shift of ITCZ. • Inversion is formed above the escarpment. stationary. • Clear, stable weather. • Moist air from the Indian Ocean can flow into the • Air moves Anticlockwise • Air moves Anticlockwise around system. interior which results in summer rainfall. around system. • Cool dry air moves into the western and • When close to SA – moist southern coasts. winds reach the coast. • May deflect mid-latitude cyclones away • Blow over warm ocean. from the coast in summer. • Warm, moist onshore winds. • Cooler land could cause Winter: precipitation. • Temperature is lower. • Cool dense air sinks onto the interior. [Sources: • Sinking air compress and heat adiabatically which https://studylib.net/doc/185856 cause lower layers to be warmer than those above. 19/session-three--factors-that- • Inversion is formed below the escarpment. influence-weather-in • When it ridges in behind cold front • Pressure system rests on escarpment and prevents weather along front will intensifies. session-three--factors-that- warm air from the Indian Ocean to reach the interior. influence-weather-in [Source: www.learn.xtra .co.za] 41

IMAGES, SYNOPTIC WEATHER MAPS AND ASSOCIATED WEATHER PATTERNS WINTER CONDITIONS SUMMER CONDITIONS CROSS SECTION [Source: Ace it, p 54] PLAN / TOP VIEW [Source: Focus, Geography Grade 12] Winter: Summer: • Anticyclones are in their northerly • Anticyclones are in their southerly position and allow cold fronts to position and prevent the cold fronts affect the country. from affecting the country. • Mid-latitude cyclones move closer to • Kalahari Anticyclone is not present ASSOCIATED WEATHER the Southern Coast. on surface but located in upper air. • Frontal rainfall over South Western • Warm air rises and forms thermal LP Cape. which are associated with • Interior is cool, dry and clear convectional thunderstorms over because of dominance of Kalahari interior. Anticyclone. • Warm, moist air moves in over the • Inversion layer is formed below the escarpment from north-east to bring escarpment. clouds and rain into interior. • Kalahari pressure system rests on • Higher temperatures and humidity escarpment and prevents warm air over the interior. from the Indian Ocean to reach the • Moisture front and squall line interior. thunderstorms develop. • Berg wind conditions develop. 42

TRAVELLING DISTURBANCES MOISTURE FRONT AND LINE THUNDERSTORMS CROSS SECTION TOP VIEW [Source: Focus, Geography grade 12] • Develop when a thermal/heat low pressure cell and a coastal low is located over South Africa. CHARACTERISTICS • Low-pressure trough forms and feeds moist air into the interior. • Occurs in summer when the low pressure dominates the interior. • The moisture front develops where the cool dry air from the South West, meets the warm moist air from the North East. • The cool air lifts the warm air which cools adiabatically, condenses and forms cumulonimbus clouds. • Rain falls to the North East of the moisture front. • No rain falls to the South West of the moisture front. NEGATIVE: POSITIVE • Thunderstorms can cause damage • Replenish water in dams in summer. • Relief drought in the interior IMPACT • Torrential downpour can cause • The heat and the pressure from flooding. the lightning turns nitrogen and in • Hail, thunder, and lightning can the air into natural fertilizer for cause damage to property and soil. crops. 43

MOISTURE FRONT AND LINE THUNDERSTORMS CROSS SECTION TOP VIEW [Source: https://www.enca.com/south-africa/cut-low-cold-front-brings-rain-and-snow • Line thunderstorms develop along the moisture front. • When a thermal low-pressure cell - and coastal low-pressure cell is located over South Africa. CHARACTERISTICS • Results in a low-pressure trough that feeds warm moist air to the interior from the northeast. • It converges with cold, dry air from the southwest. • Cold air lifts the warm air which cools adiabatically, condenses, and forms tall cumulonimbus clouds. • Associated with thunderstorms, heavy rain, and possible hail. • Can occur at night as it is not caused by heating of the atmosphere but convergence of two air masses with cold dry, dense air and warm, moist less dense air. NEGATIVE: POSITIVE • Thunderstorms can cause damage • Replenish water in dams in summer. • Relief drought in the interior IMPACT • Torrential downpour can cause • The heat and the pressure from flooding. the lightning turns nitrogen and in • Hail, thunder, and lightning can the air into natural fertilizer for cause damage to property and soil. crops. 44

COASTAL LOW-PRESSURE CELLS DIAGRAM [Source: Own sketch] • Develop during summer and winter in SA. CHARACTERISTICS • The air moves in a clockwise direction around the cell. • These low pressure sytems cause completely different weather on either side of the pressure cell. • On the one side of the pressure cell, air will move from the land to the sea and will cause warmer drier conditions. Also called offshore winds. • Other side of the pressure cell where the air moves from the sea to the land, moist cloudy conditions will develop that can lead to rain along the coastline areas. Also called onshore winds. • Low Pressure systems moves from west to east along the coastline. West coast: East coast: • Onshore winds are cold and dry • Onshore winds are warm with IMPACT with limited moisture. moisture that results in coastal • Offshore winds are warm and dry rainfall. with no moisture. • Offshore winds are warm and dry with limited moisture. 45

BERG WINDS TOP VIEW CROSS SECTION DIAGRAMS [Source: https://learn.mindset.africa/sites/default/files/resourcelib/emshare-show-note- asset/859_fdoc.pdf • Develop during winter. CHARACTERISTICS • Gusty, hot, dry winds. • Berg wind conditions occur ahead of the mid latitude cyclone, • Air flows from the Kalahari High Pressure cell to the costal low pressure. • Air subsides from the plateau and down the escarpment (off-shore winds) • Winds heats at Dry Adiabatic temperature lapse rate and become drier and hotter. • This causes hot dry uncomfortable conditions which is generally replaced quickly with cold conditions associated with the cold front. • It encourages veld fires. • Can encourages the spread of veld fires. • Veld fires impact natural environment, humans and animals. IMPACT • Farmers may lose houses, equipment and livestock. • Natural bush and grazing may be lost. • Animal habitats may be destroyed. • Dry, warm conditions can cause heat stroke and discomfort. • People and animals can suffer from dehydration. 46

C. ACTIVITY 8.1: SUB-TROPICAL ANTICYCLONES 8.1 FIGURE 8.1 shows a coastal low-pressure cell (L), associated with travelling disturbances. [Source: http://www.1stweather.com/education.php?wid=77107& prov=WC&metric=true&language=] 8.1.1 Use the isobars to prove that L is a low pressure. 8.1.2 Where does low pressure L originate? 8.1.3 In which direction does low pressure L travel between Langebaan and Cape Town? 8.1.4 What type of precipitation is associated with low pressure cell L along the West coast? 8.1.5 State the air temperature associated with the onshore flow of low- pressure cell L at Langebaan. 8.1.6 How does air rotate around low pressure cell L? 8.1.7 With which travelling disturbance is the hot, dry north easterly wind associated? (7 x 1) (7) 47

ACTIVITY 8.2: SUB-TROPICAL ANTICYCLONES 8.2 Study FIGURE 8.2, based on a diagram showing the influence of the plateau on the weather and climate of South Africa. [Source: https://learn.mindset.africa/sites/default/files/resourcelib/emshare-show- note-asset/859_fdoc.pdf 8.2.1 Does sketch X or Y indicate a summer condition? 8.2.2 Name the pressure cell A. 8.2.3 Name the ocean over which pressure cell A is located. 8.2.4 Name pressure cell C. 8.2.5 Is pressure cell associated with rising or subsiding air? 8.2.6 Will clear and stable conditions occur in sketch X or sketch Y? 8.2.7 Does a strong or weak subsidence give rise to the position of the inversion layer in sketch Y? 8.2.8 Must the inversion layer be above or below the plateau for rain to occur over the interior? (8 x 1) (8) 48

ACTIVITY 8.3: SUB-TROPICAL ANTICYCLONES 8.3 Study FIGURE 8.3, a tweet from SA Weather warning of severe thunderstorms in the Malalane region. [Source:IEB; 2020] 8.3.1 Name the main weather system responsible for the development of line thunderstorms over South Africa. (1 x 1)) (1) 8.3.2 Name ONE other hazard not mentioned in the tweet. (1 x 1) (1) 8.3.3 Using a diagram, explain how line thunderstorms develop over the interior of South Africa. (5 x 1) (5) 8.3.4 Why are line thunderstorms generally associated with summer? (1 x 2) (2) 8.3.5 Explain why there is a thicker band of clouds to the east of the moisture front (line thunderstorms). (1 x 2) (2) 8.3.6 Explain why the weather conditions associated with line thunderstorms are more severe than isolated (normal) thunderstorms. (2 x 2) (4) 49

ACTIVITY 8.4: SUB-TROPICAL ANTICYCLONES 8.4 Study FIGURE 8.4, Anticyclones over South Africa [Source: DBE; Feb – March 2016] 8.4.1 Name anticyclones A, B, and C. (3 x 1) (3) 8.4.2 Anticyclones are associated with stable weather conditions over the interior of South Africa, particularly during winter. Draw a labelled sketch to illustrate the influence of the interior anticyclone on South Africa's weather. (4 x 1) (4) 8.4.3 In a paragraph of approximately EIGHT lines, explain the influence of the intertropical convergence zone (ITCZ) on the changing position of the three anticyclones, relative to South Africa. (4 x 2) (8) 50

ACTIVITY 8.5: MAP WORK APPLICATION 8.5 Study the extract of the 3318 CD CAPE TOWN topographic map and the synoptic weather map showing a coastal low [Source: Madmapper.com] 8.5.1 In which direction will a coastal low, located north of Cape Town, move? (1 x 1) (1) 8.5.2 Give evidence that a coastal low has not yet moved along Cape Town (1 x 2) (2) 8.5.3 Describe the weather that will be experienced at Green Point after the coastal low has moved along the coast. (2 x 2) (4) 51

9. VALLEY CLIMATE IMPACT ON HUMANS, SETTLEMENT AND FARMING ANABATIC and KATABATIC WINDS SLOPE ASPECT and their IMPACT and its IMPACT VALLEY CLIMATES RADIATION FOG INVERSIONS and and the IMPACT the IMPACT FROST POCKETS and the IMPACT 52

A. KEY CONCEPTS: VALLEY CLIMATE Explanation Term Anabatic A local wind which blows up the length of the valley during the wind day, because of rising of warm air. Downslope A local wind which blows down the sides of a valley during the wind night. An area of cold air reaching a dew point temperature below Frost pocket freezing at the bottom of the valley. May occur on clear, calm winter evenings. A local wind which blows down the slope of a valley during the Katabatic wind night, because of cold subsiding air. The climate of a small area that is different to the climate of its Microclimate surroundings. Three factors contribute to valley microclimate. Fog that forms at night under clear, calm conditions. Fog caused by condensation in air that has cooled to dew point Radiation fog temperature as a result of the loss of heat though terrestrial radiation. The part of the valley or slope that does not receive any Shadow zone sunlight. Refers to the direction to which a slope faces. Slope Aspect Temperature An increase of temperature with altitude rather than the usual inversion decrease. Warm layer of air midway up a valley with cold air below as a Thermal belt result of inversion of temperature. A local wind which blows up the sides of a valley during the Upslope wind day. 53

B. NOTES/SUMMARIES ON VALLEY CLIMATE SLOPE ASPECT NORTHERN HEMISPHERE SOUTHERN HEMISPHERE CROSS SECTION [Source: Adapted from https://horticulture.tekura.school.nz/soils/soils-2/ht1032-soils-2-study-plan/soil-temperature/] IN THE SOUTHERN HEMISPHERE SLOPE ASPECT North facing slopes: South facing slopes: • Orientation of the slope ASSOCIATED WEATHER • North-facing slopes are hot, sunny and dry. • South-facing slopes are cool, • Impact change during winter • Receive more direct Sun’s rays. shady and retain moisture. and summer because of • Smaller surface area heated thus warmer. • Soils are cooler on the south- o migration of pressure • Soils are warmer as they are in the sunny zone. facing slopes as they are in systems • Farmers have to select a slope which is best suited for the shadow zone. o angle of incomming sun certain types of crops. • Area in shadow zone on the • Warmer part of valley is called the thermal belt. south facing slope are heated • The effect of aspect is greater in the winter and in only by reflection. places further from the equator. • Humans tend to build their houses on north-facing slopes because they are warmer. IMPACT • Crops that require less moisture and more sunlight will grow on the north facing slopes. • South facing slopes too cold for humans to build settlements. • Trees and shade loving plants such as ferns will grow on the south facing slopes. 54

ANABATIC AND KATABATIC WINDS ANABATIC WINDS AND KATABATIC WINDS CROSS SECTION [Source: https://www.britannica.com/science/breeze CHARACTERISTICS • The air above the slopes warms, becomes less dense and • The air above the slopes becomes cold and dense and rises on the slopes of the valley. descends down on the valley sides/slopes. • This is a warm wind which blows up a steep slope or • This is a wind that carries high density air from a higher mountain side, driven by heating of the slope through elevation down a slope under the force of gravity. insolation. • Occurs at night when the slopes cool down due to • Occurs during the day when the slopes warm due to terrestrial radiation. insolation. • Rising air removes the pollution in the valley to higher • Descending air is cold and captures the pollution on the IMPACT altitudes. valley floor which can result in the development of smog and frost. 55

INVERSION, FROST POCKETS AND RADIATION FOG INVERSION LAYER FROST POCKETS RADIATION FOG DIAGRAM [Source: Unknown] https://www.mdpi.com/2073-4433/9/10/371 https://www.wmcactionnews5.com/2018/11/20/breakdo wn-whats-fog-why-does-it-form/ • Occurs during calm, cold and clear • Low-lying area or valley floor • On cold, clear cloudless nights when winter nights. where frosts occur more frequently rapidly terrestrial radiation occurs. • When cold air drains down the valley than in the surrounding high lying • The ground becomes cool at night. CHARACTERISTICS slopes and collects at the valley floor. areas. • The air above the ground also cools. • Warm air is displaced upwards to • This is normally after a dry, clear • When this air is below due point form an inversion layer in the mid- and cold night. temperature above 0ᵒC. it causes water valley. • Cold air drains down valley slopes vapour to condense around the dust and • It is a layer of warm air trapped • If dew point temperature is below smoke particles in the atmosphere to between two layers of cold air and freezing point, it condenses to ice create radiation fog. results in the development of the crystals. • In the morning the sun heats the surface. thermal belt. • Forming frost pockets where the • The warm air rises and evaporates. • Can lead to the formation of acid rain cold air collects. • Combined with pollution in the atmosphere which corrode buildings and damage it forms smog. crops. 56

IMPACT ON HUMANS AND THE ENVIRONMENT HUMANS ENVIRONMENT • Frost pocket can cause • Traps pollutants from industries in people to settle mid-slope in the area. the thermal belt. • Acid rain occurs. IMPACT • Smog results in poor visibility • Acid rain damages fauna and flora. • Affect farmers if frost sensitive crops and is a health hazard. are grown on the valley floor. • Can cause traffic accidents • Farmers have to plant frost resistant due to poor visibility. crops. • Affects people health e.g. • Damages natural vegetation and respiratory illnesses. crops. ACTIVITY 9.1: VALLEY CLIMATE 9.1 Give ONE term for each of the following descriptions by choosing a term from the list below. Write only the term next to the question numbers (9.1.1 to 9.1.7) in the ANSWER BOOK, e.g. 9.1.8 climate. radiation fog; katabatic; temperature inversion; anabatic; smog; thermal belt; frost; aspect 9.1.1 Zone where warm air mass is trapped between colder air masses 9.1.2 A mixture of smoke and fog 9.1.3 The direction in which the slope faces in relation to insolation 9.1.4 Forms when calm conditions and clear skies occur in a valley 9.1.5 Forms on the valley floor when the air temperature is below freezing point 9.1.6 Type of wind that results from air sinking down the valley slope at night 9.1.7 Type of wind that results from air moving up the valley slope during the day (7 x 1) (7) 57

ACTIVITY 9.2: VALLEY CLIMATE 9.2 Study FIGURE 9.2 showing a diagram on valley climates. [Source: Examiners photo IEB paper of 2011] 9.2.1 Is the slope wind at A an anabatic or a katabatic wind? (1 x 1) (1) 9.2.2 B above the valley floor is a thermal belt. Give a reason for this statement. (1 x 1) (1) 9.2.3 What is the term used to describe an increase in the temperature as the height increases in the valley? (1 x 1) (1) 9.2.4 Explain why slope wind A will be more intense in winter. (2 x 2) (4) 9.2.5 Account for the low temperature that is likely to be experienced on the valley floor during winter and how farmers have to adapt their farming techniques (methods) due to the temperature change on the valley floor. (4 x 2) (8) 58

ACTIVITY 9.3: VALLEY CLIMATE 9.3 Study FIGURE 9.3 showing slope winds. [Source :Adapted from islandnet.com] 9.3.1 Name slope wind A. (1 x 1) (1) 9.3.2 State ONE factor that is responsible for the movement of slope wind A, as shown in FIGURE 9.3. (1 x 1) (1) 9.3.3 What impact do the uneven slopes have on the air moving downslope? (1 x 2) (2) 9.3.4 Explain why a temperature inversion occurs in a valley at night. (2 x 2) (4) 9.3.5 In a paragraph of approximately EIGHT lines, discuss how slope wind A can have both a positive and negative influence on vegetation growth on the valley floor. (4 x 2) (8) 59

ACTIVITY 9.4: MAP APPLICATION Study the extract from the 3322CD& 3422AB GEORGE Topographical map. M 9.4 The bottom of the valley at area M on the topographic map experiences frost in the early hours of the morning during winter. 9.4.1 Name the local/tertiary wind that is responsible for the formation of frost. (1 x 1) (1) 9.4.2 Explain how the wind named in QUESTION 9.4.1 causes frost. (2 x 2) (4) 9.4.3 Give evidence from the topographic map how the farmers adapted their farming products to accommodate the frost in the valley? (1 x 2) (2) 60

10. URBAN CLIMATE STRATEGIES TO RURAL VS URBAN REDUCE THE EFFECT CLIMATE OF URBAN CLIMATE URBAN CLIMATE POLLUTION DOMES URBAN HEAT ISLANDS 61

A. KEY CONCEPTS Term Description A form of precipitation that is acidic due to water droplets dissolving Acid rain gaseous pollution molecules. The amount of incoming solar radiation (insolation) that is reflected Albedo by the Earth’s surface. Particles of dust, smoke or salt that water vapour sticks to and on Condensation which it condenses. Also called hygroscopic nuclei. nuclei Small solid particles in the atmosphere on which water vapour Hygroscopic condenses to form tiny water droplets – these water droplets merge nuclei to form rain drops which result in cloud formation. Isotherms A line on a map connecting points having of equal temperature. Smoke, dust, fire, or water is a large quantity of it that rises into the Plume air in a column. The dome-shaped concentration of polluted air above the centre of a Pollutants city or industrial area. A mass of polluted air temporarily trapped over a city or industrial Pollution dome area. A thick, ground level fog caused when water droplets become polluted with chemicals and gasses found in the atmosphere due to Smog pollution. (A mixture of smoke and fog). Climatic conditions specific to large urban areas. Urban climate Urban heat The temperature over the city is warmer that the surrounding rural island area. 62

B. NOTES/SUMMARIES ON URBAN CLIMATE URBAN CLIMATE VS RURAL CLIMATE CROSS SECTION [Source: https://www.metlink.org/fieldwork-resource/urban-heat-island-introduction/ TEMPERATURE • Warmer due to lack of vegetation and • Cooler due to fewer transpiration. artificial surfaces and • More artificial heating, air conditioning, vehicle more vegetation cover. emission. • More artificial surfaces, tar, concrete that absorbs heat. • More dust and pollution prevent heat from escaping. POLLUTION CLIMATE CONDITIONS • More pollution and dust due to industrial activities, • Less pollution and dust combustion processes and traffic. particles. CLOUD COVER • More clouds form as there are more dust and • Fewer clouds because of pollution particles in the atmosphere. less hygroscopic nuclei. PRECIPITATION • More rain and hail due to more hygroscopic nuclei • Less rain and hail because in the atmosphere and strong updrafts of air. lower temperature and • Warmer temperature causes more evaporations. less condensation. RELATIVE HUMIDITY • Lower evaporation and relative humidity due to • Higher relative humidity lack of vegetation cover and natural resources. due to water retention in • Less surface water to evaporate. soil and vegetation. • Warmer air can hold more moisture. WIND SPEED • Wind speed is less as buildings creates friction • Wind speed is higher. and acts as windbreaks. • Turbulence is less due to • Greater turbulence because wind is channeled open space. between buildings. 63

FOG AND VISIBILITY • More fog and poorer visibility due to more • Less fog resulting in better hygroscopic nuclei and condensation nuclei. visibility. • Fog is a problem in winter when temperature inversion trap pollutants close to Earth’s surface. AIR PRESSURE • Lower because of warmer temperature. • Higher because of cooler temperature. URBAN HEAT ISLANDS Urban heat island: The temperature over the city is warmer that the surrounding rural area CROSS SECTION [Source: http://thebritishgeographer.weebly.com/urban-climates.html 64

Isotherms: A line on a map connecting points having of equal temperature. TOP / PLAN VIEW [Source: https://www.smartcitiesdive.com/ex/sustainablecitiescollective/urban-heat- islands/165241/ 65

DIFFERENCE BETWEEN DAY AND NIGHT IN URBAN HEAT ISLANDS DAY NIGHT DIAGRAM [Source: Via Afrika, Geography, p97] • Heating causes the air to expand • It is cooler so the air becomes and rise so the heat island grows denser and sinks. vertically. • Less heat results in decrease in CHARACTERISTICS • The inversion layer is elevated turbulence. vertically. • Vertical dimension decreases. • Because of vertical growth the heat • The inversion layer is closer to the is less concentrated. surface. • It may take a mushroom shape. • The heat island is more dome • It conforms to the shape of built-up shaped and pollutants are more areas. concentrated. • Pollution is dispersed over a greater • The dome is denser and shallower. area. • The trapped heat is more concentrated over CBD area. CAUSES OF DEVELOPMENT OF URBAN HEAT ISLAND AND IMPACT ON THE ENVIRONMENT AND HUMANS IMPACT CAUSES ENVIRONMENT HUMANS • Artificial surfaces in urban • Surfaces absorb heat • Increase in areas: glass, concrete, stone, during the day and discomfort. brick, tarmac, iron absorbs radiate heat into the • Exacerbated more heat. environment at night. heat stress and • Increased surface area that • Glass radiates heat deaths during can absorb heat – roof and back into the heat waves. sides of buildings. atmosphere. • Reduced visibility • Production of artificial heat: • Increase of urban because of o Combustion of factories smog due to higher smog. produce heat. temperature. • Increased costs o Air-conditioning units’ • Increase in the because of release warm air. evaporation rate. greater water o Emissions by vehicles • Creates a pollution and energy use. release heat and pollution. dome. 66

POLLUTION DOMES Pollution dome: When dust, soot and chemical emissions are trapped in the warm air of a heat island the dome becomes a pollution dome CROSS SECTION [Source: Urban Heat Island Formation, Tozam, Bulut Karaca, 2018] Pollutants act as hygroscopic nuclei and attract water vapour to them, and fog develop. Smog: A thick, ground level fog caused when water droplets become polluted with chemicals and gasses found in the atmosphere due to pollution. DIFFERENCE BETWEEN THE DAY AND NIGHT IN A POLLUTION DOME DAY NIGHT DIAGRAM [Source:urbangreenbluegrids.com]: • Convection of warm air in the center • Cooler air at night results in of the city causes a low-pressure cell pollution dome developing closer to form. to the surface. • • CHACTERISTICS Warm air rises vertically and cool This results in the pollution being down and diverges in the upper air to dense and cannot escape the spread outward to the rural areas. city. • Air circulating in the dome spreads • Pollution is more concentrated the pollution vertically and it is more because of the inversion layer disperse. closer to the earth and pollution • Pollution is carried away by upper air cannot escape the dome. divergence. • Cooler air flows into the low-pressure cell from surrounded rural area. 67

CAUSES OF DEVELOPMENT OF POLLUTION DOMES AND THE IMPACT ON THE ENVIRONMENT AND HUMANS EFFECTS CAUSES ENVIRONMENT HUMANS • Emissions by vehicle • Increase of cloud cover • Smog causes health exhausts – carbon and precipitation. problems e.g. lung monoxide and nitrogen • Acid rain develops infections, asthmatic oxide. which kills trees and attacks. • Burning of fossil fuels – erodes bricks and • Smog reduces carbon dioxide and stone. visibility and Sulphur oxide. • Old paint peeling off accidents. • The pattern of air buildings. • Lead poisoning may circulation and high levels • Contributes to global result in petrol fumes. of air pollution in the city. warming and climate change. STRATEGIES TO REDUCE URBAN HEAT ISLANDS AND POLLUTION DOMES • Make surfaces lighter color to be more reflective and less absorbent. • Greening of cities by planting trees in gardens, onto pavements and in parks. • Trees increase transpiration which decrease air temperature. • Trees absorb carbon dioxide and release oxygen. • Trees reduce energy costs as it has a natural cooling effect. • Plant roof gardens to absorb the heat and pollution. • Invest in energy saving strategies e.g. solar panels and grass roofs. • Develop sustainable public transport. • Implement building restrictions on height and materials used in building projects. • Do not use glass or reflective substances as building materials. • Controlling the amount of pollution released from factories. 68

C. ACTIVITY 10.1: URBAN CLIMATE 10.1 Refer to FIGURE 10.1 on city climates. Choose the correct word(s) from those given in brackets. Write only the word(s) next to the question number (10.1.1–10.1.8) in the ANSWER BOOK. 10.1.1 The sketch shows a (day/night) situation. 10.1.2 The inversion layer is found at a (higher/lower) altitude during the night. 10.1.3 The inversion layer (increases/decreases) pollution concentration over the city during the night. 10.1.4 The heating of the city at B is the result of (multiple reflections of heat/terrestrial radiation). 10.1.5 The channelling of wind between tall buildings (increases/decreases) the wind speed. 10.1.6 Temperature (increases/decreases) from B to C. 10.1.7 The influence of evapotranspiration on cooling the air will be (less/more) at B compared to C. 10.1.8 Area B is associated with (more/less) cloud coverage compared to area C. (8 x 1) (8) 69

ACTIVITY 10.2: URBAN CLIMATE 10.2 Study the sketch and warning below. [Source: https://www.metlink.org/fieldwork-resource/urban-heat-island-introduction/] “Alert – Due to higher temperatures, air quality is poor. Remain indoors and turn on the very aircon that uses the electricity, that’s created by the burning of fossil fuel that contributes to both the higher temperatures and poor air quality” [Source: https://www.metlink.org/fieldwork-resource/urban-heat-island-introduction/] 10.2.1 Define the concept ‘heat island’. (1 x 2) (2) 10.2.2 Describe how a heat island is formed. (1 x 2) (2) 10.2.3 Name the part of the urban area (A) that records the highest day-time temperatures. (1 x 1) (1) 10.2.4 Describe two ways in which city planners are designing urban centres to reduce the urban heat island effect. (2 x 2) (4) 10.2.5 In paragraph of approximately EIGHT lines discuss how strategies which can be implemented to reduce the heat island effect in urban areas. (4 x 2) (8) 70

ACTIVITY 10.3: URBAN CLIMATE 10.3 Refer to FIGURE 10.3 showing a pollution dome over a South African city. [Source: http://www.metlink.org/secondary/key-stage-] 10.3.1 What is a pollution dome? (1 x 2) (2) 10.3.2 Why is a pollution dome associated with an urban area? (1 x 2) (2) 10.3.3 Explain why the pollution dome is more concentrated at night. (2 x 2) (4) 10.3.4 Write a paragraph of approximately EIGHT lines explaining how pollution domes increase the maintenance costs of the built environment for people living in the city. (4 x 2) (8) 71

ACTIVITY 10.4: MAP WORK APPLICATION 10.4 EXTACT FROM THE 2926 BB THANCHU NORTH MAP [Source: P2 May /June 2019] 10.4.1 Does the mapped area receive annual rainfall or seasonal rainfall? (1 x 1) (1) 10.4.2 Give ONE reason evident on the topographic map. (1 x 2) (2) 10.4.3 The built-up nature of the suburb, Ratlou, Z on the topographic map, has resulted in fairly high temperatures. (a) Identify TWO factors evident in the mapped area that could reduce the temperature in Ratlou. (2 x 1) (2) (b) Explain how ONE of these factors mentioned in QUESTION 5.5.1 reduces the temperature in Ratlou. (1 x 2) (2) 72

11. POSSIBLE ANSWERS Revision Activity 5.1 Page 10 5.1 GLOBAL AIR CIRCULATION 5.1.1 Polar High-Pressure Cell (1) 5.1.2 Westerlies (1) 5.1.3 Subtropical High pressure (1) 5.1.4 Polar easterlies (1) 5.1.5 ITCZ/ Intertropical convergence zone (1) 5.1.6 Subpolar High Pressure Cell (1) 5.1.7 Tropical Easterlies (1) (7 x 1) (7) Revision Activity 5.2 Page 11 5.2 THE RELATIONSHIP BETWEEN AIR TEMPERATURE, AIR PRESSURE AND WIND 5.2.1 High (1) 5.2.2 Cold (1) 5.2.3 Converge (1) 5.2.4 Diverge (1) 5.2.5 Rise (1) 5.2.6 Low (1) 5.2.7 Warm (1) (7 x 1) (7) 73

6. Mid-Latitude cyclones Activity 6.1 Page 20 6.1.1 C (1) 6.1.2 C (1) 6.1.3 A (1) 6.1.4 C (1) 6.1.5 A (1) 6.1.6 B (1) 6.1.7 B (1) 6.1.8 B (1) (8 x 1) (8) Activity 6.2 Page 21 6.2.1 Warm and cold fronts are clearly visible/well defined (1) (1 x 1) (1) 6.2.2 Southern Hemisphere (1) (1 x 1) (1) 6.2.3 (4 x 1) (4) 6.2.4 The warm front approaching location A has a gentle gradient (2) No large-scale upliftment of warm air at the warm front resulting in gentle rain (2) (2 x 2) (4) 6.2.5 Strong convection before the cold front may results in the development of cumulonimbus clouds and rain (2) Heavy rainfall with thunderstorms and hail (2) Lightning associated with expected thunderstorms can be dangerous (2) Rain may cause flooding of the event (2) Rain may damage equipment (2) Insufficient undercover shelter for patrons of the event (2) Increase in wind speed can cause discomfort (2) Increase in wind speed can result in hazardous flying debris (2) Unsecured equipment may be damaged by an increase in wind speed (2) Drop in temperatures will cause discomfort for patron. (2) [ANY TWO] (2 x 2) (4) 74

Map Work application on Mid-latitude cyclones Activity 6.3 Page 23 6.3.1 West to east (1) (1 x 1) (1) 6.3.2 North easterly (1) (1 x 1) (1) 6.3.3 Wind direction –winds backing from the west to southwest will cause them to approach the harbour against the wind (2) Wind speed – Very strong to gale force winds will make their access difficult or hinder their entry (2) Cloud cover – Very thick and towering cumulonimbus clouds will restrict visibility entering the harbour (2) and result in strong convection and stormy water (2) Precipitation – Heavy rainfall and/or hail will restrict of complicate their entry (2) [Any TWO, must refer to the weather elements impact] (2 x 2) (4) 7. Tropical cyclones Activity 7.1 Page 32 7.1.1 Cumulonimbus (1) 7.1.2 Convection (1) 7.1.3 Eye (1) 7.1.4 Unstable (1) 7.1.5 Convergence (1) 7.1.6 Thunderstorm (1) 7.1.7 Warm (1) (7 x 1) (7) 75

Activity 7.2 Page 33 7.2.1 Four (1) (1 x 1) (1) 7.2.2 The map shows the southern African countries (2) cyclone path is from the eastern side towards the west (2) on the satellite image air spirals in a clockwise direction (2) [Any ONE] (1 x 2) (2) 7.2.3 Dissipating stage (2) (1 x 2) (2) 7.2.4 At a disssipating stage, air cools down when entering the temperate latitudes (2) Cooler air flows into the cyclone increasing the pressure (2) When moving inland as it can be seen in images, supply of moisture is cut of and surface friction slows it down (2) [Any TWO] (2 x 2) (4) 7.2.5 Gusty/strong winds (2) Torrential/heavy rainfall (2) Coastal flooding (2) Storm surges (2) Rough/stormy seas (2) Damage to infrastructure/property (2) Outbreak of diseases (2) Possible loss of life (2) Destruction of tourism (Kruger National Park) (2) Drowning of livestock (2) Prepare for evacuations (2) [ANY FOUR] (4 x 2) (8) Activity 7.3 Page 34 7.3.1 A category 3 hurricane (1) (1 x 1) (1) 7.3.2 Sea surface temperatures of 26,5°C and above (1) Unstable atmospheric conditions (1) Coriolis force (1) Calm conditions over the ocean surface (1) Extensive upper air divergence of winds aloft (1) Rapid large scale evaporation of moisture over ocean (1) Release of latent heat (1) [ANY ONE] (1 x 1) (1) 7.3.3 120 km/h (1) (1 x 1) (1) 7.3.4 Pressure gradient decreases when you move away from the eye (2) (1 x 2) (2) 7.3.5 Circulation and forward movement in the same direction (2) 76

Intense winds in the cyclone combines with the force of the entire (2) cyclone moving forward/westwards into the left hand quadrant (2) [ANY ONE] (1 x 2) 7.3.6 Storm surges due to strong winds will flood coasts (2) Damage to property because of flooding of low-lying coastal areas (2) Loss of human life (2) It will cause coastal erosion (2) Destruction of transport infrastructure like harbours (2) Ecosystems are disrupted (2) Strong winds can damage property (2) [ANY FOUR] (4 x 2) (8) Map Work application on Tropical cyclones Activity 7.4 Page 35 - 36 7.4.1 North West (1) (1 x 1) (1) 7.4.2 Low lying area, below 40 meters above sea level (2) It is built on the floodplain (2) It is build on marshland (2) [Any TWO] (2 x 2) (4) 7.4.3 The circulation of the winds around the low pressure of a tropical cyclone in the Southern Hemisphere is clockwise. The winds will blow towards St Lucia from a South easterly direction (2) (1 x 2) (2) 77

8. Subtropical Anticyclones and Associated Weather Conditions Activity 8.1 Page 47 8.1.1 Air pressure decreases towards the centre/lowest value in the centre (1) 8.1.2 Along the west coast of South Africa (1) 8.1.3 Southwards/South-south-eastwards (1) 8.1.4 Fog (1) 8.1.5 20˚C (1) 8.1.6 Clockwise (1) 8.1.7 Berg winds (1) (7 x 1) (7) Activity 8.2 Page 48 8.2.1 X (1) 8.2.2 South Indian High (1) 8.2.3 Indian Ocean (1) 8.2.4 Kalahari High (1) 8.2.5 Rising (1) 8.2.6 Y (1) 8.2.7 Strong (1) 8.2.8 Above (1) (8 x 1) (8) 78

Activity 8.3 Page 49 8.3.1 Low-pressure trough/moisture front (1) (1 x 1) (1) 8.3.2 flash flooding/heavy rains/lightning (1) (1 x 1) (1) 8.3.3 The candidate must show an understanding of how line thunderstorms form over the interior of South Africa They can either draw a synoptic view or a cross-section. Marks given for: • shape and drawing (2) • air masses (1) • pressure systems (1) moisture front/trough (1) (5) (5 x 1) 8.3.4 Low pressures over land during summer, draw in moisture off the oceans onto the land (2) Inversion layer above the escarpment in summer allows inflow of moist air (2) Weakened Kalahari High Pressure Cell facilitates greater vertical rising of air above the interior (2) [Any ONE] (1 x 2) (2) 79

8.3.5 Warm moist air from the east reaches the interior, cold dry dense air from the west forces warm moist less dense air to rise and large scale condensation result in dense cloud formation (1 x 2) (2) 8.3.6 Line thunderstorms are more severe: • will have a strong up-draught/stronger upliftment/ rapid rising (2) • and condensation along the moisture front (2) • continuously feeding on moisture from the ocean (2) • are a collection of cells that move in the same direction (2) consistent formation of cumulonimbus clouds along the moisture front. (2) (2 x 2) (4) Activity 8.4 Page 50 8.4.1 A - South Atlantic Anticyclone (1) B - Kalahari Anticyclone (1) C - South Indian Anticyclone (1) (3 x 1) (3) 8.4.2 (4) Air pressure decreases towards the centre/lowest value in the centre [Source: DBE; Feb-March 2016] (4 x 1) 8.4.3 THE IMPACT OF ITCZ ON ANTICYCLONES The Earth is tilted 23½° to the vertical, as it faces the sun (2) This causes the ITCZ to shift north and south of the equator from season to season (2) Pressure belts follow the apparent migration of the sun (2) In summer the 3 anticyclones are located further south (2) In winter the 3 anticyclones are located further north (2) [Any FOUR] (4 x 2) (8) 80

Map Work application on Subtropical Anticyclones and Associated Weather Conditions Activity 8.5 Page 51 8.5.1 Southwards (1) (1 x 1) (1) 8.5.2 Weather in Cape Town is overcast t(2) (1 x 2) (2) 8.5.3 Green Point will experience onshore wind (2) is cold (2) and dry (2) with limited moisture. [Any TWO] (2 x 2) (4) 9. Valley Climate Activity 9.1 Page 57 9.1.1 thermal belt (1) 9.1.2 Smog (1) 9.1.3 Aspect (1) 9.1.4 radiation fog (1) 9.1.5 Frost (1) 9.1.6 Katabatic (1) 9.1.7 Anabatic (1) (7 x 1) (7) Activity 9.2 Page 58 4 9.2 Katabatic slope (1) (1 x 1) (1) 9.2.2 Temperatures are above freezing point. (1) (1 x 1) (1) 9.2.3 Temperature inversion (1) (1 x 1) (1) 9.2.4 Slope A is a South facing slope. (2) South facing slopes in the Southern Hemisphere are cold. (2) Cold descending air in contact with the slopes will cause temperatures to drop below freezing point. (2) [Any TWO]. (2 x 2) (4) 9.2.5 Temperatures will be below freezing point because of cold descending air. (2) A frost pocket will form as a result of temperatures below freezing point. . (2) 81

Crops which cannot withstand frost will be planted on the North facing slope,where it is warmer. (2) Frost resistant crops such as deciduous fruits will be grown on the valley floor. (2) The cold conditions and frost kill pests (2) Cold conditions suit the growing conditions of these crops (2) (8) [ANY FOUR] (4 x 2) Activity 9.3 Page 59 9.3.1 Katabatic ACCEPT Downslope wind/Gravity wind (1) (1 x 1) (1) 9.3.2 Cold air becomes dense and sinks (1) Gravity (1) Pressure differences at crest and valley floor/Pressure gradient (1) [ANY ONE] (1 x 1) (1) 9.3.3 Friction (2) Slows the downward movement of air (2) [ANY ONE] (1 x 2) (2) 9.3.4 The dense, cooler air collects on the valley floor (2) Warmer air is displaced upwards (2) (2 x 2) (4) 9.3.5 Positive Influence on Valley Floor Radiation fog that covers the valley floor increases the level of moisture available to plants (2) Melting frost is a source of water, keeps the soils moist (2) Extreme cold kills unwanted pests (2) The lower temperature promotes frost resistant types of vegetation (2) Negative Influence on Valley Floor Cold dense air collects on the valley floor creating frost pockets that destroys vegetation (2) Air cools to below freezing point and frost covers plants and soil which weakens stems and leafs of vegetation (2) Black frost can destroy plants (2) Radiation fog formed on the valley floor at night reduces the level of photosynthesis in the mornings (2) Reduces the variety of crops able to be grown; only frost resistant crops can be grown (2) [ANY FOUR. MUST REFER TO BOTH POSITIVE AND NEGATIVE INFLUENCES] (4 x 2) (8) 82

Map Work application Valley Climate Activity 9.4 Page 60 9.4.1 Katabatic (1) Downslope (1) Gravitational wind (1) Mountain wind (1) [Any ONE] (1 x 1) (1) 9.4.2 The slopes cool down resulting in the air in contact with the slopes cooling down (2) The cooler air becomes heavy and dense (2) Cooler air subsides down the valley slopes (2) Cooler air accumulates on the valley floor/trapped by inversion layer (2) The cold subsiding air cools the temperature to below freezing point (2) [Any TWO] (2 x 2) (4) 9.4.3 They are farming with frost resistant fruit (1) Deciduous fruit e.g. apples, pears (1) [Accept examples[ (1 x 2) (2) 10. Rural and Urban Climate Activity 10.1 Page 68 10.1.1 day (1) 10.1.2 lower (1) 10.1.3 increases (1) 10.1.4 multiple reflections of heat (1) 10.1.5 increases (1) 10.1.6 decreases (1) 10.1.7 less (1) 10.1.8 more (1) (8 x 1) (8) 83

Activity 10.2 Page 69 10.2.1 Area of high temperatures in a city surrounded by areas of low temperatures (2) (1 x 2) (2) 10.2.2 When the build-up area absorbs and releases more heat because of building structures, glass and metal structures factories and motor-vehicles, lack of open spaces which results in the atmosphere being warmer than the surrounding rural area. (2) (1 x 2) (2) 10.2.3 CBD or city Centre. (1) (1 x 1) (1) 10.2.4 More open spaces and better air circulation due to fewer buildings. (2) More vegetation ad trees to absorb the suns heat (photosynthesis). (2) A poor and less-efficient drainage system – standing water absorbs heat and evaporates – cools the atmosphere. (2) Buildings are constructed with natural materials (timber, mud, thatch) which do not absorb so much of heat. (2) Surfaces are hardly concreted or tarred which means less heat absorbed and retained – more corrugated (untarred) roads and pathways. (2) [Any TWO] (2 x 2) (4) 10.2.5 Establish greenbelt zones to limit expansion and develop other areas. (2) Decentralisation of certain city functions – especially those requiring high pedestrian and vehicular traffic, e.g. chain stores, industries. (2) Use of building materials that reduce temperatures such as reflective roof paints (2) Establish roof gardens. (2) Providing an efficient public transport system. (2) [Any TWO] (4 x 2) (8) 84

Activity 10.3 Page 70 10.3.1 An accumulation of dust, soot and smoke (pollution) particles over the city (1) [CONCEPT] (1 x 2) (2) 10.3.2 Urban areas produce more pollution/combustion released by cars, industries and other activities/More human activities (2) (1 x 2) (2) 10.3.3 During the night subsidence is stronger/trapped closer to the ground/ inversion layer is closer to the surface at night (2) Less activity resulting in heat generation to lift pollution dome (2) Pollution covers a smaller area (2) Less convection/thermal currents to distribute pollution at night (2) [ANY TWO] (2 x 2) (4) 10.3.4 Soot accumulation on buildings results in more cleaning services needed (2) Results in acid rain which results in peeling of paint of buildings (2) Buildings must be painted more often (2) Concrete surfaces become pitted (holes) and must be maintained/renovated more frequently (2) Metal structures such as metal window frames/air conditioners become corroded because of the acid rain/renovated more often (2) Replacing damaged material with good quality/durable material is costly (2) Regular replacement/purchase of air conditioner filters (2) More regular painting of road markings as acid rain makes it peel easier (2) High pollution results in higher rainfall and can cause flood damage (2) Damaged plants in gardens to be replaced (2) Water reservoirs/dams become polluted and money spent to purify water (2) [ANY FOUR] (4 x 2) (8) 85

Map Work application Rural and Urban Climate Activity 10.4 Page 71 10.4.1 Answer: Seasonal (1) (1 x (1) 1) 5.4.2 Reason: Large number of non-perennial rivers/water (1) Irrigation is practiced as indicated by dams/furrows/wind pumps (1) Many reservoirs/storage dams visible on the topographic map (1) Experiences continental climate (1) Mapped area is sparsely vegetated (1) (2) (Any ONE) (1 x 2) 10.4.3 (a) Identify TWO factors evident in block G5 that could reduce the temperature in Ratlou. The river (2) The green areas/greenbelts/parks (2) Recreational areas (2) (Any ONE) (2 x 1) (2) (b) Explain how ONE of these factors mentioned in QUESTION 5.4.2 (a) reduces the temperature in Ratlou. The river: Absorb a lot of heat due to it being transparent (2) Will have a moderating effect on the temperature (2) Evaporation from the river has a cooling effect (2) (Any ONE) OR The green areas/recreational areas/greenbelts/parks: Absorb a lot of greenhouse gases/carbon dioxide (2) Plants absorb a lot of heat for photosynthesis (2) Evapo-transpiration has a cooling effect (2) Green areas provide shade which has a cooling effect (2) Natural surfaces are cooler than artificial surfaces (2) (Any ONE) (1 x 2) (2) 86

12. ANNEXURE A: EXAMINATION ACTION VERBS ACTION WORDS (VERBS/COMMAND WORDS) FOR ASSESSMENT VERB MEANING HOW TO ANSWER Account to answer for - explain the cause of - so as Full sentences to explain why Analyse to separate, examine and interpret critically Full sentences Classify to divide into groups or types so that things One-word answers with similar characteristics are in the same /phrases group - to arrange according to type or sort Comment to write generally about Full sentences Compare to point out or show both similarities and Full sentences differences Define to give the concise and clear meaning Full sentences Describe to list the main characteristics of something Full sentences - give an account of Differentiate to show the difference between things Full sentences Discuss to examine by means of argument, Full sentences presenting both sides and reaching a conclusion Determine to officially decide (something) especially Full sentences because of evidence or facts Distinguish to recognise the difference between things Full sentences Draw / Sketch to show by means of a sketch A diagram is required Evaluate to make an appraisal or express an opinion Full sentences concerning the value - to define, analyse and discuss Explain to make clear, interpret and spell out the Full sentences material you present Give to state facts without discussions One-word answers Identify to give the essential characteristics of - to One-word answers name Illustrate to show what something is like - to show Full sentences that something is true Justify to prove or give reasons for decisions or Full sentences conclusions, using logical argument List to write an itemised series of concise One-word answers statements Locate to find the exact place where something is One-word answers Mention providing relevant facts Full sentences Name to state something - give, identify or One-word answers mention Outline give a summary, using main points and Full sentences leaving out minor details Predict to say what you think will happen - to Full sentences foretell - to say in advance 87

VERB MEANING HOW TO ANSWER Propose to suggest a plan - to make a formal Full sentences suggestion Provide to state facts without discussions Full sentences/one- word answers Recommend to advise that something should be done Full sentences Report to produce an official statement or written Full sentences document Select to choose something from a greater whole One-word answers /Choose Solve to find a solution to something that is Full sentences causing difficulties State to present information plainly without One-word answers discussion Suggest to propose an explanation or solution Full sentences Support to show that an idea/statement is true Full sentences Tabulate to group like terms or activities under One-word specific headings answers/phrases Use to do something using a specific skill or Full sentences method Verify to check/prove that something is correct Full sentences Write to create a formal document Full sentences 88

13. REFERENCES 1. Estherhuysen P (2013), Top Class Geography, Shuter & Shooter, 2. Estherhuysen P (2013) Ace It, Shuter & Shooter 3. Study Guide (2020), Delport P and Nair K, Matthew Goniwe School of Leadership and Governance 4. https://www.40knots.net/what-are-the-trade- winds/https://www.internetgeography.net/topics/what-is-global-atmospheric- circulation/ 5. https://lotusarise.com/temperate-cyclone-extratropical-cyclone-upsc/ 6. http://www.physicalgeography.net/fundamentals/7s.html] 7. wcedonline.westerncape.gove.za 8. http://www.ux1.eiu.edu/~cfjps/1400/fronts.html) 9. https://apollo.nvu.vsc.edu/classes/met130/notes/chapter11/cf_xsect.html] 10. http://lukemweather.blogspot.com/2011/01/something-little-different-look-at.html] 11. https://www.mapsofworld.com/hurricane/distribution/spatialdistribution.html 12. https://www.legacyias.com/low-pressure-area-may-intensify-into-cyclonic-storm/ 13. http://earthobservatory.nasa.gov] 14. https://www.researchgate.net/figure/Surface-synoptic-weather-map 15. https://www.tulane.edu/~sanelson/Natural_Disasters/tropical_cyclones.htm 16. https://public.wmo.int/en/media/news/tropical-cyclone-eloise-hits-mozambique 17. www.learnxtra.co.za 18. https://wps.prenhall.com/wps/media/objects/616/631756/tropcycl/pages/structure.ht ml rom 19. http://www.ecn.ac.uk/what-we-do/education/tutorials-weather- climate/climate/oceancurrents.png 20. www.learnxtra.co.za 21. https://studylib.net/doc/18585619/session-three--factors-that-influence-weather-in 22. https://www.enca.com/south-africa/cut-low-cold-front-brings-rain-and-snow 23. https://learn.mindset.africa/sites/default/files/resourcelib/emshare-show-note- asset/859_fdoc.pdf 24. http://www.1stweather.com/education.php?wid=77107&prov=WC&metric=true&lang uage=]https://learn.mindset.africa/sites/default/files/resourcelib/emshare-show-note- asset/859_fdoc.pdf 25. https://horticulture.tekura.school.nz/soils/soils-2/ht1032-soils-2-study-plan/soil- temperature 26. https://www.britannica.com/science/breeze 27. https://www.mdpi.com/2073-4433/9/10/371 28. https://www.wmcactionnews5 29. https://www.dreamstime.com/valley-breeze-vector-illustration 30. https://www.metlink.org/fieldwork-resource/urban-heat-island-introduction/ 31. http://thebritishgeographer.weebly.com/urban-climates.html 32. https://www.smartcitiesdive.com/ex/sustainablecitiescollective/urban-heat- islands/165241/ 33. https://www.metlink.org/fieldwork-resource/urban-heat-island-introduction/ 34. joburdeastexpress.co.za 35. http://www.metlink.org/secondary/key-stage- 89

36. Singh M (2016), Excel in Geography, Tess Publishing cc 37. Dilley L P (2013), Focus Geography Grade 12, Maskew Miller & Longman 38. Adapted from islandnet.com 39. Beets P (2013), Via Africa Geography Grade 12, Via Africa publishers 40. Extract of 3318 CD CAPE TOWN, Tony Hambly PowerPoint presentation] 41. Urban Heat Island Formation, Tozam, Bulut Karaca, 2018 42. Surveys and Mapping, Private Bag X10, Mawbry, Extract of 3419 AC HERMANUS Extract of 2732 CD KULENI Extract of 3318 CD CAPE TOWN Extract of 2926BB THANCHU NORTH Extract from 2627CD PARYS Extract from 3322CD & 3422AB GEORGE 90

14. ACKNOWLEDGEMENTS The Department of Basic Education (DBE) gratefully acknowledges the following officials for giving up their valuable time and families, and for contributing their knowledge and expertise to develop this creative writing resource for the children of our country, under very stringent conditions of COVID-19. Writers: Gabisile Mncono, Neliswa Cita, Jabe Sizwe, Ellen Matsheka, Strini Naicker, Renske Pieterse, Elizabeth Scheepers, Mpumelelo Thobela, Nonhlanhla Mzila, Patricia Ndlovu, Dr Nkosinathi Sithole, Ooma Maharajh, Feroz Hanif, Edward Modise, Mpho Mongale, Raphael Hendricks, Caroline Lentsoane, Samuel Hlungwane and Raymond Maja. DBE Subject Specialist: Bulara Monyaki The development of the Study Guide was managed and coordinated by Ms Cheryl Weston and Dr Sandy Malapile. 91

Uji Ui ISBN : 978-1-4315-3500-2 hte High Enrolment Self Study Guide Series » basic education This publication is not for sale. « )) Bete Bouestion © Copyright Department of Basic Education REPUBLIC OF SOUTH AFRICA www.education.gov.za| Call Centre 0800 202 993