Atmosphere Unit Review Notes

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

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

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.

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

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.

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

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

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

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

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

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

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

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

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.