April 16 th , 2012

April 16th , 2012

Agenda: SILENCE YOUR CELL PHONE• Starting at the Syllabus

• ALL QR’s graded – ready at 11:00• Complete Atmosphere lecture TODAY• Begin Global Wind Circulation• Need 8 ½ X 11 sheet of paper• Clouds, Wind QR Due Wednesday-4-11-12• SAF field Trip – slated for 4-28-12

Monday/Wednesday lab- Making a cloudMonday/Wednesday lab- Making a cloud• I will provideI will provide

The Earth’s AtmosphereThe Earth’s Atmosphere1

The AtmosphereThe Atmospherethin layer of gas that covers thethin layer of gas that covers theentire earth --- (a sea of gasses)entire earth --- (a sea of gasses)

lets us breathelets us breathekeeps us coolkeeps us cool

very thin (approx. 65 milesvery thin (approx. 65 miles))

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Atmosphere: a mixture of gasses surrounding a planet (sea of gasses)The earth’s atmosphere:Nitrogen (N) = 78.08%Oxygen (O) = 20.95%Argon (Ar) = .93%Other:Water vapor (H2O) = 1%-4%Carbon dioxide (CO2) = .035%Helium (He)Methane (CH4)Krypton (Kr)Nitrous oxide (N2O)Hydrogen (H2)Ozone (O3)dust and pollen particles

measured asdry air

I I to breathe our atmosphere.to breathe our atmosphere.

I will get an A on my exams and quizzes.I will get an A on my exams and quizzes.

Discuss with a friend:Discuss with a friend:1.1.Define an atmosphere (not the earth’s).Define an atmosphere (not the earth’s).2. What is the composition of the earth’s2. What is the composition of the earth’s atmosphere?atmosphere?3. What are the two major compounds3. What are the two major compounds that represent less than 1% of gassesthat represent less than 1% of gasses in the atmosphere?in the atmosphere?

Atmospheric Layers and TemperatureAtmospheric Layers and Temperature

TT

TT

TT

TTThermosphereThermosphere

MesosphereMesosphere

StratosphereStratosphere

TroposphereTroposphere7 mi7 mi

30 mi30 mi

50 mi

TT

TT

TT

T

HomosphereComposition of the

atmosphere isuniform. .

HeterosphereAtmosphere is

layered by molecularweight and electric

charge.

I I to breathe our atmosphere.to breathe our atmosphere.Discuss with a friend:Discuss with a friend:

4. Draw a diagram showing the layering4. Draw a diagram showing the layering of the earth’s atmosphere.of the earth’s atmosphere.5. Show the temperature relations between5. Show the temperature relations between each atmospheric layer.each atmospheric layer.6. Define the differences between the6. Define the differences between the homospherehomosphere and and heterosphere heterosphere zones zones of the atmosphere. of the atmosphere.

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I>clickerThe atmospheric layers are arranged fromthe surface to space in which order.

a. troposphere, mesosphere, stratosphere thermosphere

b. troposphere, stratosphere, thermosphere mesosphere

c. Heterosphere, homosphered. troposphere, stratosphere, mesosphere

thermospheree. none of the above

TroposphereTroposphere• lowest layer of the atmospherelowest layer of the atmosphere• temperature decreases with altitudetemperature decreases with altitude

• environmental temperature lapse rate (ETL)environmental temperature lapse rate (ETL)• ETL – temperature decreases with altitudeETL – temperature decreases with altitude• ETL averages 6.4 ETL averages 6.4 00C/1000 m or 3.5 C/1000 m or 3.5 00F/1000 ft.F/1000 ft.

• all storm and turbulent activity takes placeall storm and turbulent activity takes place• average thickness is 12 km from surfaceaverage thickness is 12 km from surface• thickest at the equator (16 km, 10 mi.)thickest at the equator (16 km, 10 mi.)• thinnest at the polar regions (6 km, 4 mi.)thinnest at the polar regions (6 km, 4 mi.)• responsible for the greenhouse effectresponsible for the greenhouse effect

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StratosphereStratosphere• Layer lies between the troposphere andLayer lies between the troposphere and mesosphere.mesosphere.• contains strong, persistent winds that blowcontains strong, persistent winds that blow from west to east.from west to east.• Temperature increases as altitude increases.Temperature increases as altitude increases.• contains the ozone layer (Ocontains the ozone layer (O33).).

• Stratosphere heats up because the ozone absorbsStratosphere heats up because the ozone absorbs the sun’s radiation.the sun’s radiation.

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Ozone layer (O3)O

OO

• three oxygens bonded togetherthree oxygens bonded together• OO22 (molecular oxygen) + O (elemental oxygen) (molecular oxygen) + O (elemental oxygen) combine through ultra-violet energy combine through ultra-violet energy bombardment ------ continuous cyclebombardment ------ continuous cycle

• protects us from harmfulprotects us from harmful ultra-violet radiationultra-violet radiation• absorbs 97% of UV radiationabsorbs 97% of UV radiation• concentrated in the upperconcentrated in the upper stratospherestratosphere

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MesosphereMesosphere• layer between the thermosphere and layer between the thermosphere and stratospherestratosphere• 30 to 50 miles above the earth30 to 50 miles above the earth• temperature decreases with altitudetemperature decreases with altitude• has the coldest temperature of -90 has the coldest temperature of -90 00CC

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ThermosphereThermosphere

• first layer to be heated by the sunfirst layer to be heated by the sun

• uppermost layer of atmosphereuppermost layer of atmosphere

• temperature increases with altitudetemperature increases with altitude

• Where’s the upper boundary?Where’s the upper boundary?

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What is What is incomingincoming solasolar radiar radiationtion? (? (ininsolasolationtion))• energy the earth receives from the sunenergy the earth receives from the sun• travels 300,000 km/sec (186,000 mi/sec)travels 300,000 km/sec (186,000 mi/sec)• travels in “wave motion”travels in “wave motion”• Sun rays comprise the electromagnetic spectrum.Sun rays comprise the electromagnetic spectrum.

Electromagnetic Spectrum (EM scale)Electromagnetic Spectrum (EM scale)

Wavelengths the Wavelengths the human eye can see eye can see R O Y G B I V R O Y G B I V

Not harmfulNot harmful Very harmfulVery harmfulLong WavesLong Waves Short WavesShort Waves

I I to breathe our atmosphere.to breathe our atmosphere.7. Describe at least 2 major characteristics7. Describe at least 2 major characteristics of each layer in the earth’s atmosphere.of each layer in the earth’s atmosphere.8. Define 8. Define insolation.insolation.9. Draw the EM scale and label the following:9. Draw the EM scale and label the following:

types of long wave radiationtypes of long wave radiationtypes of short wave radiationtypes of short wave radiationthe visible light spectrumthe visible light spectrum

10. What wavelengths are harmful to life?10. What wavelengths are harmful to life?

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I>clicker

Electromagnetic radiation represents:

a. R O Y G B I Vb. ultra-violet and gamma short wavesc. safe short wave energyd. insolation

ThermosphereThermosphere

MesosphereMesosphere

StratosphereStratosphere

TroposphereTroposphere

most short waves most short waves are absorbedare absorbed

UV waves are absorbedUV waves are absorbedand make ozone (Oand make ozone (O33))

Most EM is longwaveMost EM is longwavebefore hitting the surfacebefore hitting the surface(visible and IR)(visible and IR)

OZONEOZONE

insolation

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H2O –the most remarkable substance on earth!

Water exists in ALL three states on the earth’s surface.

SOLID LIQUID GAS

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ICE

LIQUID

WATERVAPOR Moving from

an orderedstate to a lessordered state,

heat is absorbed.

Energy is taken in.

Moving froma less orderedstate to a moreordered state,

heat is released.

Energy moves out.

Latent heat (“hidden heat”)• the amount of heat released or absorbed during a phase change (solid to a liquid to a gas)

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Heat Absorbed

Heat Released

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Examples of latent heat:Examples of latent heat:

Water is evaporated off your skin surface and youWater is evaporated off your skin surface and youfeel cool. Why do you feel cool?feel cool. Why do you feel cool?

As water evaporates from your skin surface, heatAs water evaporates from your skin surface, heatenergy is absorbed from your skin cooling your body.energy is absorbed from your skin cooling your body.

moving from a liquid state to a vapor statemoving from a liquid state to a vapor state(latent heat is absorbed)(latent heat is absorbed)

Clouds are formed through the process of Clouds are formed through the process of condensation (changing water vapor to a suspendedcondensation (changing water vapor to a suspendedliquid).liquid).

As water vapor cools in the upper atmosphere,As water vapor cools in the upper atmosphere,it condenses to liquid releasing latent heat. it condenses to liquid releasing latent heat.

So, where does the latent heat go?So, where does the latent heat go?20

Absorbed and released latent heatis circulated throughout the earth’s

atmosphere, giving rise to clouds andvarious forms of precipitation.

To understand the formation of clouds andprecipitation, one needs to understand:

Humidity

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The Greenhouse EffectAdiabatic Processes

ConvectionCondensation


11. What is latent heat, and how does latent11. What is latent heat, and how does latent heat interact with various phase changesheat interact with various phase changes of water?of water?

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• How do you feel on a hot, humid day?Humidity:Humidity:

• Humidity represents the amount of water vaporHumidity represents the amount of water vapor in the air.in the air.• The amount of water vapor in the atmosphereThe amount of water vapor in the atmosphere is dependent on air temperature. is dependent on air temperature.

Relative Humidity (RH):Relative Humidity (RH):• RH compares the amount of water vapor in RH compares the amount of water vapor in the air to what that parcel of air can hold the air to what that parcel of air can hold according to a particular temperature. according to a particular temperature.

Dew Point:Dew Point:• At dew point, the air is saturated with water vaporAt dew point, the air is saturated with water vapor (can’t hold anymore), and the air condenses.(can’t hold anymore), and the air condenses.

RelativeHumidity Temperature

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parcelof air

parcelof air

What happens to both humidity and relative humidityas a function of atmospheric air temperature?

% of H2O vapor increases withincrease in air temperature.

condensing

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How does absorbed insolation keep theatmosphere warm?

The GreenhouseEffect

Visible and UV lightVisible and UV light““insolation”insolation”

IR heat wavesIR heat wavesare trapped are trapped inside the inside the

greenhouse.greenhouse.

The Greenhouse Effect“counterradiation”

Temperature

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.07%

.03%

trace

trace

How do greenhouse gasses contribute to counterradiation?

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Carbon dioxide absorbing infrared EM Carbon dioxide absorbing infrared EM • Infrared EM vibratesInfrared EM vibrates COCO22

• COCO22 absorbs IR EM. absorbs IR EM.• IR is released toIR is released to the earth’s surface.the earth’s surface.

AtmosphereAtmosphereheats up!heats up!

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How does the greenhouse effect work in our atmosphere?How does the greenhouse effect work in our atmosphere?

SunCOCO22 absorbs IR waves. absorbs IR waves.

Visible & UVVisible & UV

InfraredInfrared

IR returnsIR returnscounterradiation.counterradiation.

SurfaceSurface

AtmosphereAtmosphereHeatsHeats

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What do you think is the role of H2O vapor in the atmosphere?

Do we need the greenhouse effect (GHE)?• Would global temperatures be -15 Would global temperatures be -15 00CC withoutwithout the greenhouse effect? the greenhouse effect?• Is the greenhouse effect Is the greenhouse effect NATURALNATURAL??• Does the GHE act as a “blanket” Does the GHE act as a “blanket” keeping the earth warm?keeping the earth warm?• Is the greenhouse effect considered Is the greenhouse effect considered a contributor of global warming?a contributor of global warming?• The global warming debate considers:The global warming debate considers:

• Is the increase in COIs the increase in CO22 natural? natural?• Is the increase in COIs the increase in CO22 man-made? man-made?• What is the role of water vapor?What is the role of water vapor?

NO!

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I I to breathe our atmosphere.to breathe our atmosphere.12. Describe the differences between 12. Describe the differences between humidityhumidity and and relative humidityrelative humidity..13.13. What conditions are necessary regardingWhat conditions are necessary regarding atmospheric temperature and water vaporatmospheric temperature and water vapor

to reach a dew point?to reach a dew point?14. What are greenhouse gasses? Explain how14. What are greenhouse gasses? Explain how the greenhouse effect warms the earth.the greenhouse effect warms the earth.15. Why is the greenhouse effect important to 15. Why is the greenhouse effect important to the survival of life on earth?the survival of life on earth?

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I>clicker

The greenhouse effect represents:

a. changing short-wave energy into longer wave energy

b. warmer atmospheric temperaturesc. longer wave energy trapped by CO2

d. a,b, and c

e. a and b only

Formation of Clouds

unique formation?

• adiabatic principle• condensation

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Adiabatic (ey-di-uh-BA-tic) processes• describes how the temperature of an air parceldescribes how the temperature of an air parcel changes as it rises and falls in the atmospherechanges as it rises and falls in the atmosphere

Air Pressure Air Pressure HigherHigher

Air PressureAir PressureLowerLower

CompressionCompression

ExpansionExpansion

WarmsWarms

CoolsCools

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Adiabatic ProcessesAdiabatic Processes

• By definition, adiabatic processes involve By definition, adiabatic processes involve NONO heat exchangeheat exchange between the parcel of air and between the parcel of air and surrounding atmosphere.surrounding atmosphere.

•CoolingCooling and and Heating Heating take place very fast.take place very fast.

• Rising air always expands and cools adiabatically.Rising air always expands and cools adiabatically.• Subsiding air is always compressed and warmedSubsiding air is always compressed and warmed adiabatically.adiabatically.

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1,000 m (3,280 ft)

2,000 m (6,561 ft)

3,000 m (9,842 ft)

T= 12 0C 53 0F

T= 2 0C 35 0F

T= -8 0C 18 0F

DARDAR – – Dry Adiabatic RateDry Adiabatic Rate (when air is rising) (when air is rising) • Unsaturated air (dry air) will cool 10 Unsaturated air (dry air) will cool 10 00C/1000 m.C/1000 m.

Measuring adiabatic coolingDAR (Dry Adiabatic Rate)

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What if the air is SATURATED?What if the air is SATURATED?

(MAR) Moist Adiabatic Rate (MAR) Moist Adiabatic Rate varies from 4-10 varies from 4-10 00C/1000 m, C/1000 m, as an average- as an average- 6 °C / 1000 m6 °C / 1000 m

depends on water vapor content of air (more depends on water vapor content of air (more vapor = more latent heat exchange!)vapor = more latent heat exchange!)

Why is Why is DARDAR different from different from MARMAR ? ?

1,000 m (3,280 ft)1,000 m (3,280 ft)T= 12 0C 53 0FSaturated

2,000 m (6,561 ft)2,000 m (6,561 ft)T= 6 0C 43 0F

Saturated

3,000 m (9,842 ft)3,000 m (9,842 ft)TT=0 0C 32 0F

Saturated

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16. Define adiabatic processes.16. Define adiabatic processes.

17. Describe the differences between the17. Describe the differences between the DAR and MAR air masses.DAR and MAR air masses.

18. Describe what happens to a parcel of air18. Describe what happens to a parcel of air as it rises and falls under the influenceas it rises and falls under the influence of adiabatic processes. of adiabatic processes.

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I>clicker questions1.The warmer the air parcel, the _____ water vapor it can hold and relative humidity is _____.

a. less, lowerb. more, higherc. less, higherd. more, lower

2. As air is compressed it becomes _______ due to _______ air pressure. This is known as ____.

a. colder, low, adiabatic processesb. warmer, low, latent heat processesc. warmer, low, compressed aird. warmer, high, adiabatic processes

CloudsClouds::• Clouds are suspended water droplets,Clouds are suspended water droplets, ice particles, or a mixture of both.ice particles, or a mixture of both.• Cloud particles grow around a small tinyCloud particles grow around a small tiny piece of solid matter (condensationpiece of solid matter (condensation nucleus) suspended in the atmosphere.nucleus) suspended in the atmosphere.

• Aerosols (condensation nuclei)Aerosols (condensation nuclei) originate from the ocean.originate from the ocean.

Droplets of spray are lifted by wind currents, and upon Droplets of spray are lifted by wind currents, and upon evaporation, the salt xl is left behind to form condensationevaporation, the salt xl is left behind to form condensationnuclei – the beginning of a cloud.nuclei – the beginning of a cloud.

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Formation of a Cloudand Convective Precipitation

LCL

• Saturated air mass rises and reaches the “dew point” or LCL (lifting condensation level)— forming the cloud• Continued rising and condensation add more water drops.• Convection within the cloud suspends water droplets.

1

2

3

• Water drops grow in size overcoming convective updrafts and exit the cloud. This is rain.

4

1 23

4

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Condensation!Condensation! Water vapor rises in the atmosphereWater vapor rises in the atmosphere

and cools (condensing) forming clouds.and cools (condensing) forming clouds.

coolscools cools

cools coolscools

Vapor risesVapor risesVapor risesVapor rises

CondensesCondenses

LCL

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Convection inside a cloudConvection inside a cloud““turbulence”turbulence”

Hot air risesHot air rises

Air cools (sinks)Air cools (sinks)

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Orographic Precipitation• Oro (mountains) -moist air moves up and over a mountain barrier.

BakersfieldBakersfieldSantaSantaBarbaraBarbara

CoastCoastRangesRanges

SierraSierraNevadaNevada

MountainsMountainsRain ShadowRain Shadow

RainRainShadow Shadow moving moistmoving moist

airair

EvaporationEvaporation

PrecipitationPrecipitation

PrecipitationPrecipitation

Dry AirDry Air

Dry AirDry Air

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.I I to breathe our atmosphere.to breathe our atmosphere.

19. What are condensation nuclei, and what 19. What are condensation nuclei, and what role do they play in cloud formation? role do they play in cloud formation?

20. Describe the occurrence of precipitation 20. Describe the occurrence of precipitation in both the convective and orographic in both the convective and orographic

environments.environments.

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Clouds are classified based on their height and vertical development.

• high, middle, or low clouds• vertical extension into the atmosphere

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Cirrus cloudsCirrus clouds• high clouds – white and “wispy”high clouds – white and “wispy”• often have a feathery appearanceoften have a feathery appearance• appear at 20,000 feetappear at 20,000 feet• commonly appear in fair weather and pointcommonly appear in fair weather and point in the direction of air movementin the direction of air movement

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Cumulus cloudsCumulus clouds• globular individual cloud massesglobular individual cloud masses• contain a flat base (condensation level)contain a flat base (condensation level)• rising domes with anvil head topsrising domes with anvil head tops• commonly 1000 feet above the surfacecommonly 1000 feet above the surface• tremendous amounts of energy releasedtremendous amounts of energy released from condensing water vaporfrom condensing water vapor

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Stratus cloudsStratus clouds• very low “cloud sheets” very low “cloud sheets” • covers wide areas of the surfacecovers wide areas of the surface• can be considered fogcan be considered fog• a low gray blanket of moisturea low gray blanket of moisture• can bring rain or snowcan bring rain or snow

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This is the“Don’t be in the clouds

beforethe final exam”

formation.53


21. How are clouds classified?21. How are clouds classified?

22. Give two examples of cloud types in22. Give two examples of cloud types in high, middle, and low altitudes.high, middle, and low altitudes.

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April 16 th , 2012