1. Weather and Climate
Chapter pg

2. Chapter 24.1 The Atmosphere
Key Terms:
Atmosphere
Air pressure
Barometer
Troposphere
Weather
Stratosphere
Ozone layer
Mesosphere
Thermosphere
Ionosphere
Aurora

3. 24.1 Key Concepts How does the atmosphere affect conditions on Earth?
What is Earth’s atmosphere composed of?
How do pressure and density vary with altitude?
What are the characteristics of the major layers of the atmosphere?

4. 24.1 The Atmosphere The study of the atmosphere is called Meteorology.
The study of meteorology also covers the study of weather and climate.
Weather is the general condition of the atmosphere at a particular time and place.
Climate is the general weather conditions over a period of years.

5. 24.1 The Atmosphere Atmosphere: A layer of gas that surrounds Earth
The atmosphere forms a protective boundary between Earth and space and provides conditions that are suitable for life

6. 24.1 The Atmosphere
The atmosphere holds in heat and helps regulate temperatures that are suitable for life.
The two most prevalent substances in our atmosphere are carbon dioxide and water vapor (both are waste products we exhale).

7. 24.1 The Atmosphere
Air Pressure: the force exerted by the weight of a column of air on a surface.
This weight is a result of gravity
Air pressure changes with altitude.
Is most dense near surface and less dense as altitude rises.
As altitude increases, air pressure and density decreases

8. 24.1 The Atmosphere
Barometer: an instrument used to measure air pressure.
As air pressure increases, mercury in the column rises.
As air pressure decreases, mercury in the column falls.

9. 24.1 The Atmosphere Layers of The Atmosphere: Troposphere Stratosphere
Mesosphere
Thermosphere
Ionosphere

10. 24.1 The Atmosphere Troposphere: lowest layer
Contains almost all atmosphere’s water vapor
Most weather takes place here
Average height is 12 km

11. 24.1 The Atmosphere Stratosphere: 2nd layer of atmosphere
12-50 km is height
Layer in which ozone is present
Absorbs UV radiation which is harmful to life
Layer in which planes and weather balloons travel

12. 24.1 The Atmosphere Mesosphere: 3rd layer of atmosphere
50-80 km in height
At top of mesosphere temps reach -90
Air moves 320 km/hr
Meteoroids that enter the atmosphere burn up here

13. 24.1 The Atmosphere Thermosphere: outermost layer of the atmosphere
80-? Km
no boundaries marks end of atmosphere

14. 24.1 The Atmosphere Ionosphere: not a distinct layer
Region of charged particles, or ions, that overlaps the lower thermosphere
Aurora: a colorful display of light in the sky
Ions become attracted to magnetic poles of Earth and start to glow. EXAMPLE: Northern Lights

15. 24.2 The Sun and the Seasons Key terms: Rotation Revolution
Tropic zone
Temperate zones
Polar zones
Solstice
Equinox

16. 24.2 Key Concepts What are two ways in which Earth moves?
Who is Earth’s surface divided into zones based on latitude?
What causes the seasons?

17. 24.2 The Sun and the Seasons The Earth moves in two different ways
Rotation: the spinning of Earth on its axis
Causes day and night
24 hours for Earth to make one rotation
Revolution: the movement of one body around another
Earth revolves around the sun
Takes days for Earth to make one revolution

18. 24.2 The Sun and the Seasons
Latitude Zones: three regions within which the temperatures are generally the same
Tropic zone
Temperate zone
Polar zone

19. 24.2 The Sun and the Seasons
Seasons: caused by the tilt of Earth’s axis as it moves around the sun
23.5 degree tilt
Summer
Fall
Winter
Spring

20. 24.2 The Sun and the Seasons
Solstices: occurs on the two days a year when the sun is directly overhead
Northern hemisphere:
Summer solstice  June 21st
Longest day of the year
Winter solstice  December 21st
Shortest day of the year

21. 24.2 The Sun and the Seasons
Equinox: neither hemisphere is tilted towards the sun, the length of both day and night are approximately equal.
Northern Hemisphere
Vernal equinox  March 21st
Autumnal equinox  September 21st

22. 24.3 Solar Energy and Winds Key terms: Greenhouse effect Wind
Local wind
Sea breeze
Land breeze
Global winds
Coriolis effect
Monsoon
Jet stream

23. 24.3 Key Concepts
What happens to the energy the Earth receives from the sun?
How is energy transferred within the troposphere?
What causes winds?
What are some examples of local winds and global winds?

24. 24.3 The Sun and the Seasons
Some solar energy that reaches Earth’s atmosphere is reflected back, some is absorbed by the atmosphere, and some is absorbed by Earth’s surface.
50% absorbed by surface
25% reflected by clouds, dust, and gases
20% absorbed by clouds and gases
5% reflected by surface

25. 24.3 The Sun and the Seasons
Greenhouse effect: Gases in the atmosphere releases absorbed energy to the Earth’s surface
Energy is transferred in three ways:
Radiation
Conduction
Convection

26. 24.3 The Sun and the Seasons Wind: horizontal movement of air
Caused by differences in air pressure
Caused by unequal heating of Earth’s surface
Naturally flows from areas of high pressure to areas of low pressure.
As air is heated it expands and becomes less dense and rises. Cool air flows to replace it thus creating wind.

27. 24.3 The Sun and the Seasons
Local Winds: The breezes that occur where land meets a large body of water are examples of local winds.
Water has a higher specific heat than land.
The sun heats and cools the land quicker than the water.
The air above the land heats quicker than the air above the water
During the day:
The warmer air above the water will expand and rise, creating a low pressure area above the water.
The cooler air above the land flows to replace it.
During the night:

28. 24.3 The Sun and the Seasons
Sea Breeze: The cooler air over the water flows towards land
Occurs during the day time
Land Breeze: The cooler over land flows towards the water
Occurs during the night time

29. 24.3 The Sun and the Seasons
Global winds: Winds that blow over long distances from a specific direction

30. 24.3 The Sun and the Seasons
Convection Cells: global winds move in a series of huge bands
If Earth wasn’t rotating on its axis winds would flow in straight lines.

31. 24.3 The Sun and the Seasons
Coriolis Effect: the curving effect the Earth’s rotation has on all free-moving objects.
If the United States shoots a rocket towards the north pole it will travel exactly in a straight line. It’s the Earth’s rotation underneath the rocket that gives it the illusion of curving.

32. 24.3 The Sun and the Seasons
Monsoon: a wind system that is characterized by seasonal reversal of direction
Extreme land and sea breeze
Summer monsoon:
Brings cool temperatures and heavy rain
Winter monsoon:
Brings very hot and dry weather

33. 24.3 The Sun and the Seasons
Jet stream: a belt of high-speed wind in the upper troposphere
Develop at high altitudes by great differences in air pressure.

34. 24.4 Water in the Atmosphere
Humidity: the amount of water vapor in the air.
Relative Humidity: is expressed in %.
40% humidity means the air contains 40% water vapor.

35. 24.4 Water in the Atmosphere
Clouds form as warm, moist air rises and water vapor condenses in the atmosphere.
Types of clouds:
Stratus
Cumulus
Cirrus

36. 24.4 Water in the Atmosphere
Stratus: flat layers of clouds that cover much or all of the sky.
Meaning: “Spread out”
When Nimbo or Nimbus is added to cloud’s name, it means that the cloud produces precipitation.
EXAMPLE: Nimbostratus

37. 24.4 Water in the Atmosphere
Cumulus: puffy white clouds that look like piles of cotton balls with flat bottoms.
Meaning: “Heap”

38. 24.4 Water in the Atmosphere
Cirrus: Thin, white, wispy clouds, often with a feathery or veil-like appearance.
Often blow into an area ahead of rain-producing clouds.

39. 24.4 Water in the Atmosphere
Forms of precipitation:
Rain
Snow
Hail
Sleet
Freezing Rain

40. 24.5 Weather Patterns
Air Mass: forms when a large body of air becomes fairly stationary over a region of Earth’s surface or as air moves over a large, uniform region like an ocean.

41. 24.5 Weather Patterns
Fronts: a defined boundary that forms when two unlike air masses meet.
4 types of fronts:
Cold
Warm
Stationary
Occluded

42. 24.5 Weather Patterns
Cold front: occurs when a cold air mass overtakes a warm air mass.
Cumulus or cumulonimbus clouds are often produced. Causing severe wind and thunderstorms

43. 24.5 Weather Patterns
Warm fronts: occurs when a warm air mass overtakes a cold air mass.
Usually produces stratus or nimbostratus clouds and a heavy steady rain.

44. 24.5 Weather Patterns
Stationary front: two unlike air masses have formed a boundary but neither is moving.

45. 24.5 Weather Patterns
Occluded front: occurs when a warm air mass is caught between two cold air masses
A rare front that forces the warm air mass up, cutting it off from the ground and trapping it between two cold air masses.
Causes cloudy days and some precipitation.