1. Atmosphere Unit Review Notes

2. Chapter 15- Earth’s Atmosphere
Atmosphere- the layer of air that surrounds earth
Made of gases:
Mostly nitrogen- 78%
Then oxygen- 21%
Other gases- 1% (total)
water vapor, carbon dioxide, argon, etc.
It can change suddenly by events such as: volcanic eruptions, forest fires, or dust storms

3. Chapter 15- Earth’s Atmosphere
Atmosphere Characteristics- can vary from place to place on Earth
Altitude-
Distance above sea level
Higher up in altitude further away from Earth’s surface
Density-
The amount of mass in a given volume
Atmosphere is most dense closest to earth’s surface (low altitude)
Atmosphere gets less and less dense as you rise up in altitude
Temperature
The lower the altitude, the higher the temperature
As you get higher is altitude the temperature decreases
Pressure
Is the force exerted by moving air molecules
The lower the altitude, the higher the pressure
As you get higher in altitude, the pressure decreases
Measured using a barometer

4. Chapter 15- Earth’s Atmosphere
Heat Transfer in the Atmosphere
Heat=ENERGY
Heat initially comes from the sun
3 ways of heat transfer
Radiation- heat energy that travels from the sun to Earth and heats up Earth’s surface
Conduction- heat energy transfers from Earth’s surface to the atmosphere directly above it through direct contact
Convection- the molecules in the atmosphere move faster when heated by conduction and spread out. This creates an air mass that is less dense and it gets pushed upwards by the denser, colder air mass from above as it moves down.

5. Chapter 15- Earth’s Atmosphere
Layers of the atmosphere
Troposphere
Closest to earth’s surface
Warmest
Stratosphere
Air gets thinner as you move away from Earth’s surface
Ozone Layer located here
Mesosphere
Temperature decreases as you move away from Earth’s surface
Thermosphere
Closest layer to space, furthest from Earth’s surface

6. Chapter 15- Earth’s Atmosphere
Gases in the Atmosphere Absorb Radiation
Radiation comes from the sun
Ultraviolet
Infrared
Ozone
Ozone molecule O3
Located in the stratosphere
Absorbs ultraviolet radiation
Greenhouse effect
Greenhouse gases- water vapor, carbon dioxide, methane, and nitrous oxide
These gases act like a blanket that keep in reflected infrared radiation (heat).
Keeps Earth warm
If there are too many greenhouse gases, artificially put into the atmosphere (pollution), then Earth becomes too warm.

7. Chapter 16- Weather Patterns
Weather- the condition of the Earth’s atmosphere at a particular time and place
Wind
Air that moves horizontally
Moves from higher pressure towards lower pressure
Global Winds
Travel thousands of km in a steady pattern, last for weeks, created by uneven heating of Earth’s surface
Coriolis effect- cause global winds to curve because of Earth’s rotation
Jet Stream- quickly moving winds that flow in the upper troposphere
Local Winds
Change daily in a regular pattern, caused by the different heating and cooling rates of land and water, sea breezes, mountain breezes

8. Chapter 16- Weather Patterns
Evaporation- when higher temperature causes liquid water to turn to a gas (water vapor)
Condensation- when water vapor (gas) loses energy (becomes colder) and turns back into a liquid
This forms clouds when water vapor condenses on solid particles in the atmosphere
Precipitation- when the liquid or solid water in the atmosphere combine and become heavy enough to fall to Earth’s surface

9. Chapter 16- Weather Patterns
Humidity- The amount of water vapor in the air
Saturation- when the rates of evaporation and condensation are equal
Dew point- the temperature at which air with a given amount of water vapor will reach saturation
Relative Humidity- is a percent to represent the comparison of the amount of water vapor in the air with the amount of water vapor needed for saturation for that particular temperature
Fog- a cloud that rests on the ground

10. Chapter 16- Weather Patterns
Clouds
form as warm air rises and then cools to its dew point
Once cooled to dew point the water vapor condenses into tiny water droplets and ice crystals, this happens on tiny solid particles in the atmosphere
If the water droplets or ice crystals combine to become heavy enough, they will fall to earth as precipitation

11. Chapter 16- Weather Patterns
Precipitation
Types
Rain and drizzle
Freezing Rain
Sleet
Snow
Hail
Acid Rain
rain that has become much more acidic than normal because of pollution.
Can fall far from source of pollution
Is harmful to trees, lakes and wildlife
Can damage buildings or other structures

12. Chapter 17- Weather Fronts and Storms
Air mass -large volume of air with same characteristics (temperature and humidity) in different areas.
Types of air masses
Continental- form over land; dry
Maritime- form over water; moist
Tropical- form near equator; warm
Polar- form far from equator; cold
Air masses move with global winds.
If two different air masses meet the boundary between them is called a front
Cold front- when a cold air mass moves into a warm one. Pushes the warm air up and created tall clouds with brief heavy storms
Warm front- when a warm air mass moves into a cold one. The warm air slowly rises over the cold and creates flat clouds than can create many hours of rain or snow
Stationary front- when air masses first meet or when a cold or warm front stops moving. Can create a cover of clouds for days at a time

13. Chapter 17- Weather Fronts and Storms
High-Pressure Systems-
Formed when air moves around a high pressure center (the air sinks slowly down and moves outward to areas of lower pressure)
Generally brings clear skies and calm air or gentle breezes
Low-Pressure Systems-
Large weather system that surrounds a center of low pressure (begins as air moves around and inward toward the lowest pressure and then up to higher altitudes)
Creates very stormy weather
Tropical storm/hurricane-high winds and rain that get their energy from the warm tropical ocean waters. Eye of a hurricane is the center and is calm because air moves downward.
Winter storms – blizzards, lake-effect snowstorms and ice storms
Thunderstorms- forms when warm humid air rises up quickly. Effects of thunderstorms are flash floods, winds, hair and lightning.
Tornadoes- form in severe thunderstorms and most occur in North America

14. Chapter 18- Climate and Climate Change
Climate- the characteristics weather conditions in a place over a long period. Determined by temperature and precipitation patterns.
Climate can be determined by:
Latitude- closer to the equator=warmer, further from the equator=colder.
Altitude- closer to sea level=warmer, further from sea level=colder
Large bodies of water
Marine Climates- occur near the ocean, usually west coasts of continents. Winds blowing over oceans bring mild climate conditions to these west coasts.
Continental climates- occur in the interior of continents, away from water, and weather patterns can vary. There is a big difference between daytime and nighttime temperatures and winter and summer temperatures
Ocean Currents- affect climate by transferring energy from one part of an ocean to another

15. Chapter 18- Climate and Climate Change
Climates can change suddenly or slowly
Sudden Change- climates can cool when particles block sunlight (volcanic eruption, large space objects hitting Earth’s surface)
Slow Change- Climates can change as continents move the things that determine climate (latitude, altitude, etc) change as continents move
Climate changes may repeat over time
Ice ages
El Niño
Human activity can change climate
Global Warming- a global rise in temperature at a faster rate than normal due to human activities that release excess greenhouse gases.