1. Our Atmosphere
Chapter 22 Section 1

2. Warm-up
Explain to one another why the layers of the atmosphere are similar to an Oreo cookie

3. Layers of the Atmosphere

4. Layers of the Atmosphere
There are five layers of the atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere
Ionosphere

5. Troposphere Densest of all the atmospheric layers Weather occurs here
Important: The temperature drops at a constant rate as altitude increases

6. Temperature Inversion
The atmospheric condition in which warm air traps cooler air near the Earth’s surface
Traps pollutants in the air causing a haze to form over certain areas

7. Stratosphere Above the troposphere.
Gets warmer with increasing altitude
Contains no clouds and no storms
Upper part of Stratosphere is the ozone layer

8. Ozone Layer
Ozone is made of three oxygens
Absorbs solar radiation

9. Mesosphere
Coldest layer of the atmosphere
After the stratosphere

10. Thermosphere Upper layer of the atmosphere.
Gases are very far apart. How do you think this will impact the temperature?
Very hot due to the intense solar radiation

11. Ionosphere
Ionosphere reflects radio waves.
Where auroras take place.

12. Changes in the Earth’s Atmosphere
Lets talk about photosynthesis.
What is the plant taking in? What is the plant giving off?

13. Man-Made Chemicals
The ozone layer is slowly becoming depleted due to the presence of man made chemicals.
In the 1930’s a chemical was introduced to refrigerators and aerosol cans called Chlorofluorocarbons or CFC’s.
The CFC’s would cause the ozone to split apart leaving only the chlorine behind.

14. CFC’s The US government banned the use of CFC’s in 1996.
Though they are still in use by some countries today.
The damage that humans caused is still affecting us today.

15. Greenhouse Effect
The warming of the surface and the lower atmosphere of Earth that occurs when carbon dioxide water vapor and other gases in the air absorb and radiate infrared radiation
The greenhouse effect is NOT a bad thing.
If we did not have it it would be significantly colder than it is now
Greenhouse effect is responsible for keeping us warm!

16. Global Warming
Caused by an increase of carbon dioxide in the atmosphere.
Global warming has already caused the polar ice caps to start to melt.

17. Global Warming cont.

18. Global Warming Melting of icecaps causes the global sea level to rise.
Small islands are now being threatened by the rise in sea level
This rise in sea level is also killing off many of the worlds coral reefs.

19. Water and Wind
Section 2

20. Water Cycle

21. Water Cycle First step- Evaporation
Water is heated and turned into vapor

22. Water Cycle Second step- Condensation
Water vapor begins to cool causing clouds to form

23. Water Cycle Step three- Precipitation
Any form of water that falls to the Earth’s surface from the clouds

24. Humidity The amount of water vapor in the air
We feel most of the humidity in summer. Why?
Relative humidity- the actual quantity of water vapor present in the air compared with the maximum quantity that can be present at that particular temperature

25. Dew Point The temperature at which air begins to condense to a liquid.
Higher the humidity higher the dew point

26. Clouds
Are formed when warm air rises and water vapor condenses into tiny water droplets
Depending on where they form they can have different shapes and characteristics

27. Cirrus
Thin wispy clouds
Occur at high altitudes

28. Stratus
Sheet-like layered clouds
Form at lower altitudes

29. Cumulus White and fluffy clouds with flat base
Form at various altitudes

30. Cloud Names Clouds are often described using a combination of names.
Cirrostratus- high layered clouds
Altostratus- looks like a veil of clouds with the sun peeking through it
Cumulonimbus-precipitation clouds

31. Air Pressure The pressure due to the weight of the atmosphere
Instrument used to measure pressure is the barometer
Measured in millimeters of mercury

32. Wind Differences in pressure create wind
Determined by the difference in the pressure gradient.
Pressure gradient- place where air pressure varies from one place to another
Wind goes from high pressure to low pressure

33. Coriolis force Responsible for creating winds and weather patterns
Everything in the Northern Hemisphere travels to the east (right) due to the Coriolis force.

34. Global Wind Patterns
The Coriolis force plays a big role in how the Earth distributes the weather.
As the Earth rotates the wind lags behind causing different latitudes to experience different kinds of weather
The United States sits at 30°N latitude and our winds are called the Westerlies.

35. Global Wind Patterns

36. Weather and Climate
Section 3

37. Fronts
The boundary between air masses of different densities and usually different temperatures
Three types: warm cold and stationary

38. Warm Front
Occurs when a mass of warm air moves toward and over a slower mass of cold air
The air mass cools forming cirrus and cirrostratus clouds
Warm front associated with: precipitation

39. Warm Front cont.

40. Cold Front
Occurs when cold air is forced on top of warm air and rises quickly
Forms cumulonimbus clouds
Causes high winds, thunderstorms, and even tornadoes

41. Cold Front cont.

42. Stationary Front
Occurs when two fronts meet but never actually move on top of one another
Movement occurs from side to side
Similar weather to warm front

43. Climate
The average weather conditions in an area over a long period of time
Is it warmer by the North Pole or the equator?
The climate by the equator is more tropical than the North Pole because it gets more direct sunlight

44. Climate cont.
Why is it wet on one side of a mountain and dry on another?
Topography plays a role in determining an areas climate
The more rough the terrain the more diverse the climate

45. Seasons Name the four seasons we experience on Earth.
Tell me why when the Northern Hemisphere has summer that the Southern Hemisphere has winter

46. Seasons cont. Occur due to the tilt and rotation of the Earth.
Earth’s tilt is 23.5°
Fall and Spring Equinox
Summer &Winter Solsitce

47. Symbols of a Weather Map
Scientists study weather maps everyday and must learn to read a variety of symbols in order to understand what is going on that day.
H and L represent areas of high and low pressure
A circle with a arrow pointing of the end represents the cloud cover, temperature and pressure

48. Symbols cont.

49. Urban Temperature vs. Suburban Temperatures
In urban areas such as Philadelphia the temperature difference is 0.75°C higher than in suburban areas.
Why is that?
What can we do about it?