1. Climate Controls

2. What is the Difference Between Climate and Weather? Weather is the combination of temperature, precipitation, cloud cover, winds, relative humidity, and air pressure as they are experienced on a DAILY basis. Climate refers to the weather conditions of a place averaged over a 30 year period. The main elements of climate are temperature and precipitation.

3. Climate Descriptors Average Annual Temperatures Very HotAbove 25 °C Hot18°C to 24 °C Warm10°C to 17°C Cool0°C to 9°C Cold-10°C to -1°C Very Cold-11°C or colder

4. Climate Descriptors Total Annual Precipitation Very Low/ Very DryBelow 250 mm Low/ Dry 251 mm to 500 mm Medium/ Average 501mm to 1000mm High/ WetOver 1001 mm

5. SOUTHERN HEMISPHERE If the temperature graph dips in the middle, then the city must be in the southern hemisphere.

6. EQUATORIAL If the temperature graph is flat, then the city must be near the equator. The flatter the graph, the closer it is to the equator. If there is about the same amount of precipitation in each month, the city is probably near water (maritime). Singapore is near the South China Sea.

7. NORTHERN HEMISPHERE If the temperature graph rises in the middle, then the city must be in the northern hemisphere. This is a graph of the city on London. You can tell that it is near the water, because the rain is high all year.

8. Maritime and Continental A MARITIME city is one that is near a large body of water, like an ocean. –Lots of precipitation –Not a lot of difference between summer and winter temperatures A CONTINENTAL city is one that is far inland – there is not a lot of water around it. –Not as much precipitation; varies by season –Wide temperature difference between summer and winter

9. Climatic Controls Latitude Altitude Mountain Barriers Land and Water Surfaces Ocean Currents Air Masses Pressure Cells Pollution

10. 1. LATITUDE General: As you go north or south of the equator the temperature will get colder and the precipitation will be drier Latitude is the single most important influence on climate

11. LATITUDE Why? The same amount of energy hits the Earth, but as you go farther north or south of the equator, the Earth curves, so the same energy has to hit a larger area. Therefore the energy to the north and south is less and the energy at the equator is more.

12. Earth Sun

13. Earth Sun The same amount of energy comes from the sun. Less land to cover at the equator – more surface area at the poles

14. Specifics: Equator (tropics) 0 - 30°N and 0 - 30°S very hot temperatures with no seasons Mid – Latitudes 30°N to 60° N and 30° S to 60° S summers range from long and hot near 30° to cool and short near 60° Arctic 60° N to 90°N and 60°S 90°S summers will be short and cool, winters will be very, very, very, very long and very, very, very, very cold LATITUDE

15. 2. Altitude General The higher up you go, the colder it gets

16. Altitude Why? At the Earth’s surface the molecules of air are packed tightly together, so they bump into each other all the time. This “bumping” creates friction which makes heat. As you go higher, the molecules spread out more, so there is less and less “bumping”. This means there is also less friction, so there is less heat.

17. Altitude Specifics The ENVIRONMENTAL LAPSE RATE is the rate at which temperature goes down as altitude increases. In dry areas the ELR is 10ºC/ 1000m In wet areas the ELR is 6.4ºC/ 1000m

18. 3. Mountain Barriers General Mountains affect the precipitation and the wind patterns of the land around them.

19. Mountain Barriers Why? Chinook Condensation Precipitation

20. Mountain Barriers As the wind hits the mountain, it can only go up and over, or around the barrier. If there is a valley opening, the wind most often will redirect itself there. This means that the wind going into the valley will be very strong.

21. 4. Land and Water Surfaces General Land near large bodies of water have more even temperatures throughout the year than land in the middle of the continent.

22. Land and Water Surfaces Why? During the day and in summer, water stores heat from the sun as LATENT HEAT In cooler temperatures (night or winter), the heat is gradually released On land, the sun’s heat is quickly absorbed, but quickly released, so there is a big difference between day and night temperatures, or summer and winter temperatures

23. Land and Water Surfaces SOLAR ENERGY WARMER AIR COOLER AIR LATENT HEAT MUCH REFLECTED ENERGY LITTLE REFLECTED ENERGY

24. Land and Water Surfaces Specifics: Maritime areas have cooler summers and warmer winters (less TEMPERATURE VARIATION). They also usually have more precipitation. Continental (inland) areas have warmer summers and colder winters (higher temperature variation). They also usually have less precipitation.

25. 5. Ocean Currents General An ocean current is a large amount of ocean water moving in one direction. Warm currents start nearer the equator and flow either north or south. Cold currents start farther north or south and flow toward the equator.

26. Ocean Currents General Warm currents usually provide warmer temperatures and more precipitation. Cold currents usually provide cooler temperatures and less precipitation.

27. Ocean Currents Why? Air above a warm current is warm Air above a cold current is cool Warm air can hold a lot of moisture Cool air can only hold a little moisture

28. Ocean Currents Why? When the warm water flows into the cold water the water starts to evaporate quickly. The air above the cold water is cool so the evaporated air quickly condenses and precipitates

29. Ocean Currents Why? When the cold current moves into warm water, the air above it is warm, so it can absorb the water that evaporates without precipitating

30. Ocean Currents

31. 6. Air Masses General Air masses are huge bodies of air that contain similar weather. Air masses are described by where they come from. The names of the masses give you some idea of what the mass is like.

32. Air Masses mP – Maritime Polar – Moist and Cold mT – Maritime Tropical – Moist and Warm cA – Continental Arctic – Dry and Cold cP – Continental Polar – Dry and Very Cold cT – Continental Tropical – Dry and Hot

34. Air Masses Why? When air masses meet, a FRONT is created. We name the front for the temperature of the advancing air mass. A Warm Front would be an air mass with a higher temperature overtaking an air mass with a lower temperature.

35. Air Masses Specifics: When the warm front occurs, the warm air is forced up over the cold air it has caught up to. The result is very widespread heavy cloud cover and often, light rain.

37. Air Masses Specifics: When a cold front occurs, the cold air forces the warm air it has caught up to upward very quickly. Because the air is forced up so quickly is causes towering CUMULUS CLOUDS and heavy storms.

39. 7. Pressure Cells General Low pressure cells are columns of air that are created when warm air rises. The low pressure is caused by the air leaving the space. High pressure cells are columns of air that are created when cool air sinks. The high pressure is caused by more air coming into the space.

41. Pressure Cells Low Pressure Cells As the warm air rises, it cools causing condensation. This condensation makes clouds which may precipitate. Low pressure cells are linked to precipitation, storms, and when combined with strong winds, tornadoes. This type of precipitation is called CONVECTION PRECIPITATION

42. Pressure Cells High Pressure Cells As the cool air sinks, it warms up, so it can hold more moisture. So there is very little precipitation. High pressure cells are linked to clear, calm weather.

44. 8. Air Pollution Greenhouse Effect As our world becomes more INDUSTRIAL and more populated, we produce more carbon dioxide and other gases. These gases trap the sun’s heat energy within the atmosphere, causing the temperature to increase. As the level of gases continues to rise, the temperature of the earth will also rise.

46. Air Pollution The weakening of the Ozone Layer Ozone is a gas that is similar to oxygen (O²), but contains three, not two molecules of oxygen (O³). Ozone forms a protective barrier around the earth, keeping harmful UV rays from entering our atmosphere. As pollutants break down the ozone into oxygen this layer is thinned and even has a hole in it. The result of the loss of the ozone layer will be to threaten all life on Earth.

47. Analysis Chart What makes a climate hot? Latitude –Closer to the equator Altitude –Lower altitude (elevation) Mountain Barriers –No effect Land and Water Surfaces –Further inland Ocean Currents –Near a warm current Air Masses –Tropical What makes a climate cold? Latitude –Closer to the poles Altitude –Higher altitude (elevation) Mountain Barriers –No effect Land and Water Surfaces –Near water Ocean Currents –Near a cold current Air Masses –Arctic/Polar

48. Analysis Chart What makes a climate wet? Latitude –Closer to the equator Altitude –No effect Mountain Barriers –Windward side Land and Water Surfaces –Near water Ocean Currents –Near a warm current Air Masses –maritime What makes a climate dry? Latitude –Closer to the poles Altitude –No effect Mountain Barriers –Leeward side Land and Water Surfaces –Farther inland Ocean Currents –Near a cold current Air Masses –continental