Chapter 15 – The AtmosphereChapter 15 – The AtmosphereAtmosphereAtmosphere – A mixture of gases composed of 78% nitrogen and 21% – A mixture of gases composed of 78% nitrogen and 21%

oxygen.oxygen.Gravity holds the gases close to the Earth making it thicker with higher Gravity holds the gases close to the Earth making it thicker with higher

pressure near the surface and thinner with lower pressure at higher pressure near the surface and thinner with lower pressure at higher altitudes.altitudes.

The Layers of the Atmosphere:The Layers of the Atmosphere:1.1. Troposphere Troposphere – the lowest, densest and closest layer to the surface of the – the lowest, densest and closest layer to the surface of the

Earth containing 90% of the mass of the atmosphere.Earth containing 90% of the mass of the atmosphere.2.2. Stratosphere Stratosphere – the gases in this layer are thin and do not mix. Thin with – the gases in this layer are thin and do not mix. Thin with

very little moisture.very little moisture.3.3. MesosphereMesosphere – the coldest layer characterized with a decrease of – the coldest layer characterized with a decrease of

temperature with increasing altitude (inverse relationship). This is the temperature with increasing altitude (inverse relationship). This is the middle layer but also is one of the highest layers.middle layer but also is one of the highest layers.

4.4. ThermosphereThermosphere – one of the highest layers containing too few air – one of the highest layers containing too few air molecules to successfully transfer any thermal energy. Temperatures may molecules to successfully transfer any thermal energy. Temperatures may reach 1000reach 1000°C.°C.

5.5. IonosphereIonosphere – composed of the upper mesosphere and lower – composed of the upper mesosphere and lower thermosphere where nitrogen & oxygen atoms absorb harmful solar thermosphere where nitrogen & oxygen atoms absorb harmful solar radiation. These gas particles become electrically charged (ionized) and radiation. These gas particles become electrically charged (ionized) and form the auroras when energized by solar particles. This layer also form the auroras when energized by solar particles. This layer also reflects radio waves back to the surface.reflects radio waves back to the surface.

Atmospheric HeatingAtmospheric HeatingEnergy from the sun reaches the Earth’s surface Energy from the sun reaches the Earth’s surface

in the form of electromagnetic waves called in the form of electromagnetic waves called radiation. Only about radiation. Only about two billionthstwo billionths (2/1,000,000,000,000) of the sun’s energy ever (2/1,000,000,000,000) of the sun’s energy ever reaches the Earth’s surface and half of that get reaches the Earth’s surface and half of that get absorbed by the water and land (50%).absorbed by the water and land (50%).

Thermal ConductionThermal Conduction – The transfer thermal – The transfer thermal energy through a conductive material. Similar to energy through a conductive material. Similar to cooking. Heat is transferred from the flame to cooking. Heat is transferred from the flame to the pot to the food.the pot to the food.

ConvectionConvection – The transfer of heat by the – The transfer of heat by the molecules of a liquid or a gas. The movement molecules of a liquid or a gas. The movement created when warm air rises and cold air sinks.created when warm air rises and cold air sinks.

Greenhouse EffectGreenhouse Effect – The warming of the surface and lower – The warming of the surface and lower atmosphere caused by water vapor, carbon dioxide, sulfur atmosphere caused by water vapor, carbon dioxide, sulfur dioxide, nitric oxide (greenhouse gases) that absorb radiation dioxide, nitric oxide (greenhouse gases) that absorb radiation and transfer the thermal energy to the surroundings.and transfer the thermal energy to the surroundings.

Global WarmingGlobal Warming – The unnatural, gradual average global – The unnatural, gradual average global temperature increase due to an increased concentration of temperature increase due to an increased concentration of greenhouse gases.greenhouse gases.

Global & Local Winds:Global & Local Winds:WindWind – The movement of air caused by differences in air – The movement of air caused by differences in air

pressure. The greater the pressure differential, the stronger the pressure. The greater the pressure differential, the stronger the wind. Differences in air pressure are caused by the unequal wind. Differences in air pressure are caused by the unequal heating of the Earth’s surface with warm air rising at the heating of the Earth’s surface with warm air rising at the Equator and cooler air sinking at the Poles.Equator and cooler air sinking at the Poles.

Convection (Hadley) CellsConvection (Hadley) Cells – Large, circular patterns that the air – Large, circular patterns that the air travels in, separated by high and low pressure belts located travels in, separated by high and low pressure belts located about every 30about every 30° latitude.° latitude.

Coriolis EffectCoriolis Effect – The curving of the Earth’s winds and ocean – The curving of the Earth’s winds and ocean currents caused by the Earth’s rotation.currents caused by the Earth’s rotation.

Global Winds:Global Winds:Polar EasterliesPolar Easterlies – Winds that blow from the poles to 60 – Winds that blow from the poles to 60° latitude.° latitude.WesterliesWesterlies – The flow of air to the poles from the west to the east. – The flow of air to the poles from the west to the east.

This is the opposite of the Trade Winds and blow from 30° to This is the opposite of the Trade Winds and blow from 30° to 60° latitude.60° latitude.

Trade WindsTrade Winds – Winds that blow from 30° south latitude to 30° – Winds that blow from 30° south latitude to 30° south latitude. Named by sailor who traveled from Europe to the south latitude. Named by sailor who traveled from Europe to the Americas.Americas.

DoldrumsDoldrums – Located at the Equator where the Trade Winds meet – Located at the Equator where the Trade Winds meet and rise creating a very calm center of low pressure.and rise creating a very calm center of low pressure.

Horse LatitudesHorse Latitudes – A region located at 30° latitude where the air – A region located at 30° latitude where the air sinks creating a high pressure, windless area. Many of the sinks creating a high pressure, windless area. Many of the world’s deserts are located here.world’s deserts are located here.

Jet StreamJet Stream – A narrow band of high altitude, high speed winds – A narrow band of high altitude, high speed winds that blow up to 400 km./hr. (240 m.p.h.) in the upper that blow up to 400 km./hr. (240 m.p.h.) in the upper troposphere and lower stratosphere.troposphere and lower stratosphere.

Local WindsLocal Winds – Winds that move air short distances and can blow – Winds that move air short distances and can blow from any direction. Can be created by a shoreline, mountain from any direction. Can be created by a shoreline, mountain range or even a forest fire.range or even a forest fire.

Mountain and Valley breezesMountain and Valley breezes – Caused by differences in – Caused by differences in temperature created by changes in elevation. Valley breeze by temperature created by changes in elevation. Valley breeze by day, mountain breeze by night. Breezes and winds are named day, mountain breeze by night. Breezes and winds are named by where they blow from.by where they blow from.

Air PollutionAir Pollution – The contamination of the air by pollutants from – The contamination of the air by pollutants from human and natural sources. Can cause coughing, headaches human and natural sources. Can cause coughing, headaches and lung cancers.and lung cancers.

Primary PollutantsPrimary Pollutants – put directly from their source directly into – put directly from their source directly into the air. Car exhaust is the #1 human primary pollutant.the air. Car exhaust is the #1 human primary pollutant.

Secondary PollutantsSecondary Pollutants – A primary pollutant that reacts with other – A primary pollutant that reacts with other pollutants to create a new pollutant such as ozone and smog.pollutants to create a new pollutant such as ozone and smog.

Indoor air pollutionIndoor air pollution is the result of the use of cleaners, heaters, is the result of the use of cleaners, heaters, dirty ductwork, chemicals from carpet, etc. Can be reduced with dirty ductwork, chemicals from carpet, etc. Can be reduced with a proper ventilation system that mixes household air with a proper ventilation system that mixes household air with outdoor air.outdoor air.

Acid PrecipitationAcid Precipitation – precipitation that contains acids from air – precipitation that contains acids from air pollution.pollution.

AcidificationAcidification – Acid precipitation changing the acidity of the – Acid precipitation changing the acidity of the water and soil causing harmful effects.water and soil causing harmful effects.

Acid ShockAcid Shock – A rapid change of the acidity of a body of water – A rapid change of the acidity of a body of water killing fish and damaging eggs of fish and amphibians. Most killing fish and damaging eggs of fish and amphibians. Most harmful in our area with the spring thaw.harmful in our area with the spring thaw.

Ozone HoleOzone Hole – Harmful effects of chemicals called CFC’s – Harmful effects of chemicals called CFC’s (chlorofluorocarbons) that are breaking down the ozone (O(chlorofluorocarbons) that are breaking down the ozone (O33) into ) into oxygen (Ooxygen (O22) allowing harmful ultraviolet (UV) radiation to reach ) allowing harmful ultraviolet (UV) radiation to reach the Earth’s surface.the Earth’s surface.

Cleaning Up Air Pollution:Cleaning Up Air Pollution: Allowance Trading SystemAllowance Trading System – Limits the amount of pollutants that – Limits the amount of pollutants that

a company can release.a company can release. Hybrid CarsHybrid Cars – Uses both gasoline & electric power. – Uses both gasoline & electric power. ScrubbersScrubbers – Devices that remove some pollutants before they – Devices that remove some pollutants before they

are released into the air. Usually mounted on the tops of are released into the air. Usually mounted on the tops of smokestacks.smokestacks.

Cleaner fuels, catalytic converters, more efficient auto engines, Cleaner fuels, catalytic converters, more efficient auto engines, etc. etc.