Factors which influence climate

1. Factors which influence climate Today’s Aim - • To learn the different factors that affect climate. Keywords Latitude, Equator, Sea Breeze, Prevailing Wind, North Atlantic Drift, Altitude.

2. Factors that affect CLIMATE Brainstorm the factors which you think effect climate in the back of your book – discuss with people around you.

3. Factors Affecting Climate 1 - Latitude • The further you travel away from the equator the cooler it gets. Why is this? • This is because the Earth is curved. Look at the picture above. The sun rays hitting the Earth at a higher latitude are spread out over a greater area. Over the Equator the rays are concentrated in to a smaller area – this is why it is hot at the equator and very cold at the poles. • However, the picture is more complicated than this as other factors have a bearing on the climate in different parts of the world.

4. Factors Affecting Climate 2 - Altitude This is the effect of height on temperature - the higher you go, the colder it gets. The sun heats up the earth’s surface and then heat is radiated back up into the atmosphere.

5. Factors Affecting Climate 3 - Prevailing Winds The movement of the earth’s winds starts at the equator, where it is hottest. There are certain set patterns of winds called prevailing winds, which means that direction winds travels most of the time. Wind affects the climate where it has travelled over the : Maritime - ocean Continental - overland

6. Other Factors Affecting Climate • Distance from the coast • Ocean Currents • Shelter • How built up a place is.

7. Major Climatic Regions Maritime Tundra Tropical Mediterranean Hot Deserts Tropical Grasslands

8. Summary • The Climate is the average weather over many years. • Many areas around the world have similar climates • Climates are affected by latitude, altitude, , distance from the sea, ocean currents and prevailing winds.

9. Questions(Copy out the question before answering it please apart from Q4) • Why is it very cold in the Arctic? • Why are high mountains covered in snow and ice? • Why are inland areas hotter than coastal areas in the summer? Draw a diagram to help explain your answer. • Try questions 4 and 5 in Geog 2, page 37

10. July 1 Sea is cooler than the land in the wet season (summer). So air over the land heats up and rises, creating low pressure. 2 As it cools it moves towards the sea. 3 It then descends to the sea creating high pressure. 4 Wind moves from high to low pressure and as it travels over sea it picks up water so is able to rain, creating the ‘monsoon (wet) season’. 1 – Indian Monsoons LOW HIGH

11. What do you need to know today? • There are many different causes of weather in the atmosphere. 2. Many different atmospheric processes affect the world’s weather.

12. World Wind and Pressure Belts • Colour high pressure areas BLUE and low pressure RED 2. Add Hadley Cells, latitude numbers and wind direction arrows

13. How is a Hadley Cell Formed? As air cools it can no longer rise Air rises and cools in the atmosphere Cold air sinks at the Horse Latitudes Sun heats equator Ground heats air WIND moves between high and low pressure HIGH LOW

14. World Wind and Pressure Belts

15. January 1 Land is cooler than the sea in the dry season (winter). So air over the sea heats up and rises, creating low pressure. 2 As it cools it moves towards the land. 3 It then descends to the ground creating high pressure. 4 Wind moves from high to low pressure and as it travels over land it does not pick up water so is dry. 1 – Indian Monsoons HIGH LOW

16. 2 – Tropical Revolving Storms HURRICANES in the Caribbean TYPHOONS in the North West Pacific CYCLONES in the Indian Ocean

17. 2 – Tropical Revolving Storms The Inter-Tropical Convergence Zone (ITCZ) • The ITCZ has:- • air masses on either side of it which are similar • no clear fronts • no warm sector • hurricanes, typhoons and cyclones • the sea has to be 27°C or above

18. 2 – Tropical Revolving Storms The Process of Hurricane Formation • Water vapour evaporates from the sea very quickly as the sea is extremely warm. • Air rises very rapidly. • Water vapour condenses as it rises. • Huge cumulo-nimbus clouds develop. • Torrential rain falls from the huge clouds. • Pressure gradient is steep causing very fast winds which swirl around the centre. • Dry air at the top of the hurricane sinks into the calm ‘eye’ of the storm (the centre). • The winds and rain caused by hurricanes can kill many people.

19. Summary of Climate • The global pattern is affected by: Latitude; land and sea; relief & ocean currents • ITCZ- max heating and air is forced to risedaily thunderstorms • Sub-tropical high pressure descending air  low rainfall • Low pressure  depressions and anticyclones from tropical air meeting cold polar air • Passage of air mass moist, dry, cold or warm.