AtmosphereAtmosphere

Chapter 23Chapter 23

MeteorologyMeteorology

Study of the atmosphere.Study of the atmosphere.Meteorologists are scientists Meteorologists are scientists

who study all the who study all the characteristics of the characteristics of the atmosphere.atmosphere.

They also study weather and They also study weather and climate.climate.

WeatherWeather

Is the general condition of Is the general condition of the atmosphere at a the atmosphere at a particular time and place.particular time and place.

Includes temperature, air Includes temperature, air movements, and moisture movements, and moisture content.content.

ClimateClimate

General weather General weather conditions over many conditions over many years.years.

MeteorologyMeteorology

Meteorologists apply their Meteorologists apply their forecasting skills to special fields forecasting skills to special fields such as agriculture, aviation, such as agriculture, aviation, forestry, or health.forestry, or health.

Composition of the Composition of the AtmosphereAtmosphere

Air is a mixture of chemical elements Air is a mixture of chemical elements and compounds.and compounds.

Most abundant elements in the air Most abundant elements in the air are gases: nitrogen, oxygen, and are gases: nitrogen, oxygen, and argon.argon.

Most abundant compounds are Most abundant compounds are gases: carbon dioxide and water gases: carbon dioxide and water vapor.vapor.

Water vaporWater vapor

Added to air by evaporation.Added to air by evaporation. Most evaporation comes from the Most evaporation comes from the

oceans, but also includes ponds, oceans, but also includes ponds, lakes, streams, and the soil.lakes, streams, and the soil.

Plants give off water vapor during Plants give off water vapor during transpiration.transpiration.

It is removed during evaporation: It is removed during evaporation: condensations and precipitation. condensations and precipitation.

ozoneozone

Another important substance in the Another important substance in the upper atmosphere in a form of upper atmosphere in a form of oxygen. oxygen.

Protects the earth from harmful Protects the earth from harmful ultraviolet rays of the sun.ultraviolet rays of the sun.

Human activities have harmed the Human activities have harmed the ozone layer: CFCs-ozone layer: CFCs-chlorofluorocarbons such as from chlorofluorocarbons such as from refrigerators and air conditioners.refrigerators and air conditioners.

Atmospheric DustAtmospheric Dust

Atmosphere contains various kinds of Atmosphere contains various kinds of tiny solid particles.tiny solid particles.

Includes mineral particles lifted from Includes mineral particles lifted from fields by winds.fields by winds.

Volcanic dust and microscopic Volcanic dust and microscopic organisms.organisms.

Oxygen in the AtmosphereOxygen in the Atmosphere

Amount is the result of natural Amount is the result of natural process.process.

Animals, bacteria, & plants remove Animals, bacteria, & plants remove oxygen from the air as part of their life oxygen from the air as part of their life processes.processes.

Forest fires, burning of fuels, & Forest fires, burning of fuels, & weathering of some rocks also use up weathering of some rocks also use up oxygen.oxygen.

Produce during photosynthesis.Produce during photosynthesis.

Nitrogen in the AtmosphereNitrogen in the Atmosphere

Amount of nitrogen in the atmosphere Amount of nitrogen in the atmosphere is maintained through the nitrogen is maintained through the nitrogen cycle.cycle.

Nitrogen moves from the air to the Nitrogen moves from the air to the soil, to plants & animals, & back again soil, to plants & animals, & back again to the air.to the air.

Nitrogen is removed from the air Nitrogen is removed from the air mainly by the action of nitrogen-fixing mainly by the action of nitrogen-fixing bacteria.bacteria.

Nitrogen fixationNitrogen fixation

Microscopic organisms live in the soil Microscopic organisms live in the soil & on the roots of certain plants. & on the roots of certain plants. These bacteria convert the nitrogen These bacteria convert the nitrogen to a form that plants can use.to a form that plants can use.

Ammonia nitrateAmmonia nitrate

Atmospheric PressureAtmospheric Pressure

Gravity pulls the gases of the Gravity pulls the gases of the atmosphere toward the earth’s atmosphere toward the earth’s surface & holds them there.surface & holds them there.

Due to gravity, 99% of the total mass Due to gravity, 99% of the total mass of the atmospheric gases is found of the atmospheric gases is found with in 32 km of the earth’s surface.with in 32 km of the earth’s surface.

Atmospheric PressureAtmospheric Pressure

Ration of the force of the air to the Ration of the force of the air to the area of the surface on which it area of the surface on which it presses.presses.

If you have been in an airplane or If you have been in an airplane or high in the mountains, you have felt high in the mountains, you have felt the effect of sensation on your ears. the effect of sensation on your ears. A popping sensation or your ears A popping sensation or your ears filling up with air.filling up with air.

Mercurial BarometerMercurial Barometer An instrument that measures pressure.An instrument that measures pressure. Atmospheric pressure presses on the Atmospheric pressure presses on the

liquid mercury in a well at the base of liquid mercury in a well at the base of the barometer.the barometer.

A reading of 760 mm of mercury A reading of 760 mm of mercury indicates standard atmospheric indicates standard atmospheric pressure, or 1 atmosphere.pressure, or 1 atmosphere.

Weather maps use millibars (mb). 1 Weather maps use millibars (mb). 1 mb is equal to 0.001 of standard mb is equal to 0.001 of standard atmospheric pressure.atmospheric pressure.

Types of BarometersTypes of Barometers

Aneroid barometer is a type of Aneroid barometer is a type of barometer that does not contain barometer that does not contain mercury. Aneroid means “without mercury. Aneroid means “without liquid”.liquid”.

Altimeter can also measure altitude Altimeter can also measure altitude above sea level.above sea level.

Layers of the AtmosphereLayers of the Atmosphere

4 layers are: troposphere, 4 layers are: troposphere, stratosphere, mesosphere, and stratosphere, mesosphere, and thermosphere.thermosphere.

TroposphereTroposphere

Atmospheric layer closest to the Atmospheric layer closest to the earth’s surface.earth’s surface.

In Greek it means, “change”.In Greek it means, “change”. Almost all the water vapor & carbon Almost all the water vapor & carbon

dioxide in the atmosphere is found dioxide in the atmosphere is found here.here.

Tropopause-temperature remains Tropopause-temperature remains nearly constant.nearly constant.

StratosphereStratosphere

Layer of the atmosphere that Layer of the atmosphere that extends upward from the tropopause extends upward from the tropopause to an altitude of 50 km. to an altitude of 50 km.

Stratosphere is the high-temperature Stratosphere is the high-temperature zone, that marks the upper zone, that marks the upper boundary.boundary.

MesosphereMesosphere

Above the stratopause & extending Above the stratopause & extending to an altitude of about 80 km is this to an altitude of about 80 km is this atmospheric layer.atmospheric layer.

Mesopause is the upper boundary Mesopause is the upper boundary that is marked by a return to that is marked by a return to increasing temperatures.increasing temperatures.

ThermosphereThermosphere

Atmospheric layer above the Atmospheric layer above the mesopause.mesopause.

Temperature increases steadily with Temperature increases steadily with altitude.altitude.

Thermometer cannot accurately Thermometer cannot accurately measure the temperature here measure the temperature here because the air is thin.because the air is thin.

Thermosphere continuedThermosphere continued

Ionosphere is the lower region of the Ionosphere is the lower region of the thermosphere, at an altitude of 80 thermosphere, at an altitude of 80 km to 550 km.km to 550 km.

Exosphere os the zone of indefinite Exosphere os the zone of indefinite altitude. It extends for thousands of altitude. It extends for thousands of kilometers above the earth.kilometers above the earth.

Air PollutionAir Pollution

Any substance that is harmful to Any substance that is harmful to people, animals, plants, or property.people, animals, plants, or property.

Substances found in air that are Substances found in air that are pollutants: sulfur dioxide, carbon pollutants: sulfur dioxide, carbon monoxide, lead, & hydrocarbons.monoxide, lead, & hydrocarbons.

Mains source is the burning of fossil Mains source is the burning of fossil fuels.fuels.

Air Pollution continuedAir Pollution continued

Acid precipitation is another harmful Acid precipitation is another harmful side effect of the burning of fossil side effect of the burning of fossil fuels.fuels.

Air pollution can become a more Air pollution can become a more serious problem as result of certain serious problem as result of certain weather conditions.weather conditions.

Temperature inversion is when a Temperature inversion is when a layering of warm air on top of cool air.layering of warm air on top of cool air.

Controlled by preventing air pollutants.Controlled by preventing air pollutants.

Section Review 23.1Section Review 23.1

1. What are the two most abundant 1. What are the two most abundant elements in dry air at sea level?elements in dry air at sea level?

2. What does a barometer 2. What does a barometer measure?measure?

3. In which layer of the atmosphere 3. In which layer of the atmosphere do weather changes occur?do weather changes occur?

AnswersAnswers

1. Nitrogen & oxygen1. Nitrogen & oxygen 2. atmospheric pressure2. atmospheric pressure 3. the troposphere3. the troposphere

23.2 Solar Energy & the 23.2 Solar Energy & the AtmosphereAtmosphere

Earth’s atmosphere is heated in Earth’s atmosphere is heated in several ways by the transfer of several ways by the transfer of energy from the sun.energy from the sun.

RadiationRadiation

All of the energy that the earth All of the energy that the earth receives from the sun travels through receives from the sun travels through space between the earth & the sun.space between the earth & the sun.

Includes all forms of energy that Includes all forms of energy that travels through space as waves.travels through space as waves.

Cannot see the forms called X-rays & Cannot see the forms called X-rays & radio waves.radio waves.

Radiation continuedRadiation continued

Travels through space in the form of Travels through space in the form of waves at high speed.waves at high speed.

Wavelength is the distance from one Wavelength is the distance from one wave crest.wave crest.

Various types of radiation differ in Various types of radiation differ in the length of their waves.the length of their waves.

Visible light consists of waves you Visible light consists of waves you see in different colors.see in different colors.

Radiation continuedRadiation continued Wavelengths shorter than visible include Wavelengths shorter than visible include

ultraviolet rays, z-rays, & gamma rays.ultraviolet rays, z-rays, & gamma rays. Longer wavelengths include infrared Longer wavelengths include infrared

waves & radio waves.waves & radio waves. Electromagnetic waves make up all forms Electromagnetic waves make up all forms

of radiation.of radiation.

Radiation continuedRadiation continued

Electromagnetic spectrum is a Electromagnetic spectrum is a complete range of wavelengths.complete range of wavelengths.

Most energy reaching the earth from Most energy reaching the earth from the sun is in the form of the sun is in the form of electromagnetic waves.electromagnetic waves.

Skin CancerSkin Cancer

The amount of ultraviolet radiation The amount of ultraviolet radiation that does reach the earth’s surface that does reach the earth’s surface causes sunburn on skin that is causes sunburn on skin that is exposed to direct sunlight too long.exposed to direct sunlight too long.

ScatteringScattering

Clouds, dust, and gas molecules in Clouds, dust, and gas molecules in the atmosphere affect the path of the atmosphere affect the path of radiation from the sun.radiation from the sun.

Means that water droplets and dust Means that water droplets and dust suspended in the atmosphere reflect suspended in the atmosphere reflect and bend the rays.and bend the rays.

ReflectionReflection

20 % of solar energy is absorbed by 20 % of solar energy is absorbed by atmosphere.atmosphere.

30 % is scattered back into space or 30 % is scattered back into space or is reflected from clouds or earth’s is reflected from clouds or earth’s surface.surface.

50 % is absorbed by the surface.50 % is absorbed by the surface. Chart on page 465 shows reflection Chart on page 465 shows reflection

and absorption by different surfaces.and absorption by different surfaces.

AlbedoAlbedo

The fraction of solar radiation The fraction of solar radiation reflected by a particular surface is reflected by a particular surface is albedo.albedo.

Albedo of the moon is .07 %. Albedo of the moon is .07 %. What percent of the total solar What percent of the total solar

energy reaching the moon is energy reaching the moon is reflected?reflected?

Absorption & Infrared Absorption & Infrared EnergyEnergy

The warmth of the sun you feel is The warmth of the sun you feel is infrared rays.infrared rays.

Infrared rays produced by materials Infrared rays produced by materials on the earth’s surface is mostly on the earth’s surface is mostly absorbed by water vapor and carbon absorbed by water vapor and carbon dioxide.dioxide.

Greenhouse EffectGreenhouse Effect

Process by which the atmosphere Process by which the atmosphere traps infrared rays over the earth’s traps infrared rays over the earth’s surface.surface.

Increased carbon dioxide levels have Increased carbon dioxide levels have caused the earth to be a warmer caused the earth to be a warmer planet.planet.

Global warminGlobal warmin

Variations in TemperatureVariations in Temperature

Factors causing changes in Factors causing changes in temperature are:temperature are:

LatitudeLatitude ElevationElevation

Conduction and ConvectionConduction and Convection

Conduction is when molecules in a Conduction is when molecules in a substance move faster as they are substance move faster as they are heated.heated.

Type of energy transfer in which vibrating Type of energy transfer in which vibrating molecules pass heat along to other molecules pass heat along to other vibrating molecules by direct contact.vibrating molecules by direct contact.

Convection is the energy transfer of heat Convection is the energy transfer of heat through the movement of heated through the movement of heated material. material.

Section 23.2 ReviewSection 23.2 Review

1. What type of solar radiation 1. What type of solar radiation causes sunburn?causes sunburn?

Answer: ultrvioletAnswer: ultrviolet

2. Why is the atmospheric pressure 2. Why is the atmospheric pressure lower beneath a mass of warm air lower beneath a mass of warm air than beneath a mass of cold air?than beneath a mass of cold air?

Answer: Answer:

Because warm air is less dense than Because warm air is less dense than cold air and thus presses down on cold air and thus presses down on the earth with less force than an the earth with less force than an equal volume of cold air.equal volume of cold air.

23.3 Winds23.3 Winds

Because the earth receives more Because the earth receives more solar energy at the equator than at solar energy at the equator than at the poles, there is a belt of low air the poles, there is a belt of low air pressure at the equator.pressure at the equator.

Global WindsGlobal Winds

Circulation of the atmosphere as well Circulation of the atmosphere as well as the oceans is affected at the as the oceans is affected at the rotation of the earth on its axis.rotation of the earth on its axis.

Rotation of the earth causes surface Rotation of the earth causes surface winds in the Northern Hemisphere to winds in the Northern Hemisphere to deflect to the right and those in the deflect to the right and those in the Southern Hemisphere to the left. Southern Hemisphere to the left. This motion is called the This motion is called the Coriolis Coriolis effect.effect.

Convection CellsConvection Cells

This is the air flowing from the This is the air flowing from the equator completes three looping equator completes three looping patterns of flow.patterns of flow.

Northern and Southern Hemispheres Northern and Southern Hemispheres each have three convection cells.each have three convection cells.

Trade WindsTrade Winds

Winds in both hemispheres flowing Winds in both hemispheres flowing toward the equator between 30 toward the equator between 30 degrees and 0 degrees latitude.degrees and 0 degrees latitude.

Trade winds flowing from the Trade winds flowing from the northeast are called northeast are called northeast trades.northeast trades.

Trade winds in the Southern Trade winds in the Southern Hemisphere are called Hemisphere are called southern southern trades.trades.

DoldrumsDoldrums

This is a trade wind system of the This is a trade wind system of the Northern and Southern Hemispheres Northern and Southern Hemispheres meet at the equator in this narrow meet at the equator in this narrow zone.zone.

Horse latitudesHorse latitudes

This is the subtropical high-pressure This is the subtropical high-pressure belt.belt.

The surface winds here are weak and The surface winds here are weak and changeable. The name horse changeable. The name horse latitudes was given to this region.latitudes was given to this region.

WesterliesWesterlies

Flow of winds in both Northern and Flow of winds in both Northern and Southern Hemispheres.Southern Hemispheres.

Northern Hemisphere, the westerlies Northern Hemisphere, the westerlies are southwest winds.are southwest winds.

Southern Hemisphere, the westerlies Southern Hemisphere, the westerlies are northwest winds.are northwest winds.

Located in the belt between the 40 Located in the belt between the 40 degree & 60 degree latitude.degree & 60 degree latitude.

Polar EasterliesPolar Easterlies

Third wind belt near the poles.Third wind belt near the poles. Poleward of the belt of westerlies, at Poleward of the belt of westerlies, at

about 60 degree latitude, is a belt of about 60 degree latitude, is a belt of low pressure.low pressure.

Subpolar lows result from warm air Subpolar lows result from warm air moving poleward from subtropical moving poleward from subtropical high is lifted by cold polar air moving high is lifted by cold polar air moving toward the equator.toward the equator.

Polar easterliesPolar easterlies

Surface winds created by the polar Surface winds created by the polar high pressure are deflected by the high pressure are deflected by the Coriolis effect.Coriolis effect.

Strongest coming off the Antarctica.Strongest coming off the Antarctica.

Jet StreamsJet Streams Bands of high-speed winds exist in Bands of high-speed winds exist in

the upper troposphere & lower the upper troposphere & lower stratosphere over both the Northern stratosphere over both the Northern & Southern hemisphere. Known as & Southern hemisphere. Known as upper westerly winds.upper westerly winds.

Pressure differs because of the Pressure differs because of the temperature of polar air & middle-temperature of polar air & middle-latitude air differs so greatly.latitude air differs so greatly.

Cold polar air is much denser than Cold polar air is much denser than the warmer air of the middle the warmer air of the middle latitudes. latitudes.

Polar Jet StreamPolar Jet Stream

Resulting pressure differences of the Resulting pressure differences of the air from the cold dense air produces air from the cold dense air produces the polar jet stream.the polar jet stream.

Polar jet streams are important Polar jet streams are important because they control the path of because they control the path of storms & have an effect on the storms & have an effect on the airline routes.airline routes.

BreezeBreeze

Gentle winds that extend over Gentle winds that extend over distances of less than 100 km are distances of less than 100 km are called breezes.called breezes.

These winds are our local winds that These winds are our local winds that are not apart of global wind belts.are not apart of global wind belts.

Land & Sea BreezesLand & Sea Breezes Warmer air above the land rises, and Warmer air above the land rises, and

the cool air above the water moves the cool air above the water moves in to replace it.in to replace it.

Cool wind moving from water to land Cool wind moving from water to land is called a sea breeze.is called a sea breeze.

Overnight the land cools more Overnight the land cools more rapidly than the water does, and the rapidly than the water does, and the sea breeze is replaced by a land sea breeze is replaced by a land breeze.breeze.

Land breeze flows from the cooler Land breeze flows from the cooler land to the warmer water.land to the warmer water.

Mountain & Valley BreezeMountain & Valley Breeze In mountain regions during the In mountain regions during the

daylight hours, a gentle valley breeze daylight hours, a gentle valley breeze blows up the slopes.blows up the slopes.

Then, cooler air descends from the Then, cooler air descends from the mountain peaks, creating a mountain mountain peaks, creating a mountain breeze.breeze.

Section 23.3 ReviewSection 23.3 Review

1. What are the results of the 1. What are the results of the Coriolis effect on wind flow?Coriolis effect on wind flow?

Answer: Winds veer to the right in Answer: Winds veer to the right in the Northern Hemisphere and to the the Northern Hemisphere and to the left in the Southern Hemisphere.left in the Southern Hemisphere.

Review cont-Review cont-

2. What surface wind belt flows in 2. What surface wind belt flows in the middle latitudes?the middle latitudes?

Answer: WesterliesAnswer: Westerlies

Review cont-Review cont- 3. On a camping trip on the Oregon 3. On a camping trip on the Oregon

coast, you decide to hike to the ocean, coast, you decide to hike to the ocean, but you are not sure of the direction. but you are not sure of the direction. The time is 4:00 P. M. How might the The time is 4:00 P. M. How might the breeze help you find the ocean? Why?breeze help you find the ocean? Why?

Answer: If you walk against the Answer: If you walk against the breeze, you can find the ocean. The breeze, you can find the ocean. The cool sea breeze, blowing from the cool sea breeze, blowing from the water to land, begins in the afternoon.water to land, begins in the afternoon.