Introducing climate what is it?

1. Introducing climatewhat is it? But before we look at the different parts of climate, lets make sure we know the difference between it and weather first! Have a tape measure of some sort for this lesson!

2. Weather? Climate ? Which is which? • WEATHER describes conditions in the atmosphere at any time or short period of time. • Weather conditions can change suddenly. • Today may be warm and sunny, tomorrow may be cool and cloudy. • Weather conditions include rain, snow, sleet, hail, fog, mist, sunshine, wind, temperature and thunderstorms.

3. Weather? Climate ? Which is which? • CLIMATE describes surface and atmospheric conditions over a longer time period or over a large geographical area. • The climate of an area is concerned with the AVERAGE weather conditions which are taken over a year or more. • Climate changes slowly, usually over decades, centuries and thousands of years. • The Earth has many climate regions. • Britain is in the Temperate Climate Belt, with winters that are not too cold and summers that are not too hot.

4. In summary • Weather describes the daily conditions of a particular place • whereas • climate describes the general pattern over time

5. Try these – weather or climate? • “I think we should move to France where it is warmer.” • “My washing will never dry today.” • “December is wet and cold.” • “Where should we go for our skiing holiday this year?” • “There is too much fog for the plane to land.” • “Bananas grow in Jamaica because it is hot.” • “Sports Day is cancelled, it is raining too much.” • “Take your coat to school today.” • “It’s October, it’ll be getting cold soon, I’d better put the heating on.”

6. Today we will look at • Words to describe roughly the temperature and the precipitation • What is it about a place that makes the climate of a place the way it is

7. Temperature • To be able to identify a climate you need to be able to describe the temperature of the hottest and coldest months and the temperature range. • The describing words for temperature are shown on the thermometer on the left.

8. Wet stuff from the sky is precipitation • So the following are types of precipitation • rain • snow • hail or • ice (this was in the air before it landed)

9. Precipitation • You also need to be able to describe the total amount of annual rainfall - that is how many millimetres fall in a year. The pattern of rainfall is also important.

10. Lets practice! • July24th 2009in Surrey, it was 36.50C • Buntingford (Hertfordshire) recorded a minimum temperature of -12.3C on the 7th Jan this year. • World Temperatures today: • http://www.metoffice.gov.uk/education/teachers/latest_weather_data_world.html • What is like and where?

11. Lets practice! • Annual Rainfall • Wigboro Wick Farm, St Osyth in Essex has 500mm of precipitation each year • Crib Goch in Snowdonia, Wales has 4470 millimetres a year • (oops – what shall we call more than 2000mm?) • Rome 760 mm • Madrid 470mm • Tabora , Tanzania 880mm • Lloro, Colombia (on the edges of the Amazon 13.3 meters • [I know all the others are in mm but this would be 13,300 mm – a bit hard to image – how tall are you? How many of you would need to stand on each other’s head for the top one to breath?]

12. The world as you have never seen it before! From world mapper Where is it wettest or driest? • It says, ’Territory size shows the proportion of worldwide precipitation falling on land that falls there.’ What do you think that means? Land area http://www.worldmapper.org/index.html

13. What makes the climate different in different places? • Its latitude: how far from the equator the place is • Its altitude: how high it is above sea level • How far from the sea it is • Its prevailing winds (the direction from which the wind comes most often) • Ocean currents – these may bring warm water to the colder areas, warming the coastal parts but also bringing rain. Cold currents from the artic regions cool the coasts

14. The latitude • This affects temperature in 2 ways • One has to do with the tilt of the earth that changes with the seasons • The other has to do with the height of the sun in the sky, and so how much each patch of earth is warmed

15. The height of the sunLets look at a diagram same width ray, not spread out at all, much hotter same width ray, more spread out –not so hot look how much thicker the air is

16. Earth’s Seasons Tilt of the Earth’s axis towards or away from the sun creates the seasons SUMMER (Northern Hemisphere) When the north pole tilts toward thesun, it gets more radiation – more warmth during the summer North Pole Equator Earth South Pole When the north pole tilts toward thesun, the south pole tilts away So when it’s summer in the north, it’s winter in the south WINTER (Southern Hemisphere)

17. Earth’s Seasons Tilt of the Earth’s axis towards or away from the sun creates the seasons WINTER (Northern Hemisphere) When the north pole tilts away from the sun, it gets less radiation – So it’s colder during the winter North Pole Equator Earth South Pole When the north pole tilts away from thesun, the south pole tilts toward it… When it’s winter in the north, it’s summer in the south SUMMER (Southern Hemisphere)

18. In summary • The higher the latitude (the further from the equator) • the more heat from the sun is absorbed by air • the more spread out the rays of the sun are so the bigger area has to share the heat that is left • the greater the difference between summer and winter

19. The altitude • The higher a place is above sea level, the colder it gets. • In Scotland, Braemar (339m) has an annual average temperature of 6.4°C, • While average at Ben Nevis (1344m) is -0.3°C. • On Everest(8,848m), the average temperature is -40°C compared to an average of 15°C at sea level

20. Distance from the sea ( or continentality) • Places near the ocean, tend to have more rain than those in land • at least some of the wind will come from across the sea, picking up water vapour as it travels • the land next to the sea is higher and therefore relief rain will tend to happen • Places near the sea will tend to have warmer winters but cooler summers that those in land. Why?

21. Warmer Summer air Why the sea is warmer in winter and cooler in summer than the land In Summer Land near the sea is kept cooler than inland by the cooler sea Water is a liquid and is transparent. So the radiant heat is spread out more – to a great depth. So it does not heat up so much. Inland is solid and opaque so the top layer collects all the heat and so it gets hotter.

22. Why the sea is warmer in winter and cooler in summer than the land In Winter Land near the sea is kept warmer than inland by the warmer sea More warmth leaves the land Some warmth leaves the sea The warmth from the Summer goes deeper and so is slower to cool down Inland the surface heat is lost quickly, and so the land cools down in winter

23. So in Summary • In Summer inland areas are warmer than the coast or the land nearby. • But in Winter inland areas are colder than the coast and land near it

24. The prevailing wind • If the most usual wind comes a cross the sea, it tends to have more water vapour and hence bring rain • If the most usual wind comes across the land, it is likely to be dry and so not bring much rainfall

25. The prevailing wind in the UK is from the SW across the Atlantic – wet!But if you are in New York, the prevailing wind is NW across the US mainland – dry Look at the Sahara -they come from a long stretch of land from Asia – that explains a thing or 2! But it is not just wet winds that make the coastal regions wetter

26. Where is it wetter in the UK? • What pattern can you see? • Do you know why this pattern exists?

27. Formation of Relief Rainfall Occurs in the mountains on the west coast of Britain Evaporation of water from the ocean

28. Formation of Relief Rainfall Occurs in the mountains on the west coast of Britain Onshore moisture laden winds Evaporation of water from the ocean

29. Formation of Relief Rainfall Occurs in the mountains on the west coast of Britain Air cools down Onshore moisture laden winds Mountains on the west coast of Britain forces the air to rise Evaporation of water from the ocean

30. Formation of Relief Rainfall Water vapour Condenses to form clouds Further cooling leads to precipitation Air cools down Onshore moisture laden winds Mountains on the west coast of Britain forces the air to rise Evaporation of water from the ocean

31. Formation of Relief Rainfall Water vapour Condenses to form clouds Air cools down Onshore moisture laden winds Air moving down the mountain, gets warmer and so reabsorbs any remaining water vapour. NO MORE RAIN Evaporation of water from the ocean

32. Relief Rainfall • Air is forced to rise and cools by 1°C per 100m. • As the water vapour in the air condenses, it forms clouds and rains. • The air starts to descend and begins to warm up again. • As air warms up, it can hold more water vapour - clouds disappear and rain stops. This side is known as a RAINSHADOW. Relief rain is formed when air is forced to cool as it rises over relief (height) features in the landscape (hills or mountains).

33. Ocean currents Which parts of which continents are colder than you would otherwise expect? And which warmer?

34. Homework • Some fairly straightforward questions on what we have talked about in class today