2thin layer of gas that covers the entire earth --- (a sea of gasses) The Atmospherethin layer of gas that covers theentire earth --- (a sea of gasses)lets us breathekeeps us coolvery thin (approx. 65 miles)2
3Atmosphere: 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%measured asdry airOther: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
4I to breathe our atmosphere. Discuss with a friend: Define an atmosphere (not the earth’s).2. What is the composition of the earth’satmosphere?3. What are the two major compoundsthat represent less than 1% of gassesin the atmosphere?I will get an A on my exams and quizzes.
5T T T T Atmospheric Layers and Temperature Thermosphere Mesosphere 50 miTMesosphereTStratosphere30 miTTroposphere7 mi
6Heterosphere Homosphere T T T T Atmosphere is layered by molecular weight and electriccharge.THomosphereTComposition of theatmosphere isuniform.TT
7I to breathe our atmosphere. Discuss with a friend: 4.Draw a diagram showing the layeringof the earth’s atmosphere.5. Show the temperature relations betweeneach atmospheric layer.6. Define the differences between thehomosphere and heterosphere zonesof the atmosphere.8
8Troposphere temperature decreases with altitude lowest layer of the atmospheretemperature decreases with altitudeenvironmental temperature lapse rate (ETL)ETL – temperature decreases with altitudeETL averages 6.4 0C/1000 m or 3.5 0F/1000 ft.all storm and turbulent activity takes placeaverage thickness is 12 km from surfacethickest at the equator (16 km, 10 mi.)thinnest at the polar regions (6 km, 4 mi.)responsible for the greenhouse effect9
9Stratosphere mesosphere. contains strong, persistent winds that blow Layer lies between the troposphere andmesosphere.contains strong, persistent winds that blowfrom west to east.Temperature increases as altitude increases.contains the ozone layer (O3).Stratosphere heats up because the ozone absorbsthe sun’s radiation.10
10Ozone layer (O3) O O O three oxygens bonded together O2 (molecular oxygen) + O (elemental oxygen)combine through ultra-violet energybombardment continuous cycleprotects us from harmfulultra-violet radiationabsorbs 97% of UV radiationconcentrated in the upperstratosphere11
11Mesosphere layer between the thermosphere and stratosphere 30 to 50 miles above the earthtemperature decreases with altitudehas the coldest temperature of -90 0C12
12Thermosphere first layer to be heated by the sun uppermost layer of atmospheretemperature increases with altitudeWhere’s the upper boundary?13
13Wavelengths the human eye can see What is incoming solar radiation? (insolation)energy the earth receives from the suntravels 300,000 km/sec (186,000 mi/sec)travels in “wave motion”Sun rays comprise the electromagnetic spectrum.Electromagnetic Spectrum (EM scale)Wavelengths the human eye can seeR O Y G B I VVery harmfulNot harmfulShort WavesLong Waves14
14I to breathe our atmosphere. 7. Describe at least 2 major characteristicsof each layer in the earth’s atmosphere.8. Define insolation.9. Draw the EM scale and label the following:types of long wave radiationtypes of short wave radiationthe visible light spectrum10. What wavelengths are harmful to life?15
15Thermosphere Mesosphere OZONE Stratosphere Troposphere 16 insolation most short wavesare absorbedMesosphereOZONEUV waves are absorbedand make ozone (O3)StratosphereMost EM is longwavebefore hitting the surface(visible and IR)Troposphere16
16H2O –the most remarkable 17H2O –the most remarkablesubstance on earth!GASSOLIDLIQUIDWater exists in ALL three states on the earth’s surface.
17WATER VAPOR LIQUID ICE Latent heat (“hidden heat”) 18 Moving froma less orderedstate to a moreordered state,heat is released.Energymoves out.Moving froman orderedstate to a lessordered state,heat is absorbed.Energy istaken in.LIQUIDICELatent heat (“hidden heat”)the amount of heat released or absorbed duringa phase change (solid to a liquid to a gas)
19Examples of latent heat: Water is evaporated off your skin surface and youfeel cool. Why do you feel cool?As water evaporates from your skin surface, heatenergy is absorbed from your skin cooling your body.moving from a liquid state to a vapor state(latent heat is absorbed)Clouds are formed through the process ofcondensation (changing water vapor to a suspendedliquid).As water vapor cools in the upper atmosphere,it condenses to liquid releasing latent heat.20So, where does the latent heat go?
20Absorbed and released latent heat is 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:HumidityThe Greenhouse EffectAdiabatic ProcessesConvectionCondensation22
21I to breathe our atmosphere. 11. What is latent heat, and how does latentheat interact with various phase changesof water?12. Describe the differences betweenhumidity and relative humidity.13. What conditions are necessary regardingatmospheric temperature and water vaporto reach a dew point?26
22RH compares the amount of water vapor in How do you feel on a hot, humid day?Humidity:Humidity represents the amount of water vaporin the air.The amount of water vapor in the atmosphereis dependent on air temperature.Relative Humidity (RH):RH compares the amount of water vapor inthe air to what that parcel of air can holdaccording to a particular temperature.Dew Point:At dew point, the air is saturated with water vapor(can’t hold anymore), and the air condenses.23
27How do greenhouse gasses contribute to counterradiation? .03%trace.07%trace30
28Atmosphere heats up! Carbon dioxide absorbing infrared EM Infrared EM vibratesCO2CO2 absorbs IR EM.IR is released tothe earth’s surface.Atmosphereheats up!31
29Sun Atmosphere Heats Surface 32 How does the greenhouse effect work in our atmosphere?What do you think is the role of H2O vapor in the atmosphere?SunCO2 absorbs IR waves.IR returnscounterradiation.Visible & UVAtmosphereHeatsInfraredSurface32
30Would global temperatures be -15 0C Do we need the greenhouse effect (GHE)?Would global temperatures be -15 0Cwithout the greenhouse effect?Is the greenhouse effect NATURAL?Does the GHE act as a “blanket”keeping the earth warm?Is the greenhouse effect considereda contributor of global warming?The global warming debate considers:Is the increase in CO2 natural?Is the increase in CO2 man-made?What is the role of water vapor?NO!33
31I to breathe our atmosphere. 34 14. What % of EM is reflected back to space,and what % is absorbed at the earth’s surface?15. How is the earth’s albedo defined?16. What are greenhouse gasses? Explain howthe greenhouse effect warms the earth.17. Why is the greenhouse effect important tothe survival of life on earth?34
32Formation of Clouds adiabatic principle condensation unique formation? 35
33Cools Warms Adiabatic (ey-di-uh-BA-tic) processes 37 describes how the temperature of an air parcelchanges as it rises and falls in the atmosphere37CoolsExpansionAir PressureLowerAir PressureHigherCompressionWarms
34Adiabatic Processes 38 By definition, adiabatic processes involve NO heat exchange between the parcel of air andsurrounding atmosphere.Cooling and Heating take place very fast.38Rising air always expands and cools adiabatically.Subsiding air is always compressed and warmedadiabatically.
35Adiabatic Cooling 39 2000 m 1000 m Surface Air molecules continue to expand, decreasing temp.Temp: 10 oC50 oF1000 mAir risesTemp: 20 oC68 oFDecreasing air pressure causesair molecules to expand, and airtemperature decreases.Air risesSurfaceAtmospheric pressurecompresses air molecules,keeping air temp at 30 oC.Temp: 30 oC86 oFAdiabatic Cooling
36All cooling is done by the expansion of air. 40Measuring adiabatic coolingDAR (Dry Adiabatic Rate)T= -8 0C 18 0F3,000 m (9,842 ft)2,000 m (6,561 ft)T= 2 0C 35 0F1,000 m (3,280 ft)T= 12 0C 53 0FDAR – Dry Adiabatic Rate (when air is rising)Unsaturated air (dry air) will cool 10 0C/1000 mor 5.5 0F/1000 ft.All cooling is done by the expansion of air.
37What if the air is SATURATED? 41What if the air is SATURATED?T=0 0C 32 0FSaturated3,000 m (9,842 ft)T= 6 0C 43 0FSaturated2,000 m (6,561 ft)T= 12 0C 53 0FSaturated1,000 m (3,280 ft)(MAR) Moist Adiabatic Ratevaries from C/1000 m, as an average °C / 1000 mWhy is DAR different from MAR ?depends on water vapor content of air (more vapor = more latent heat exchange!)
38I to breathe our atmosphere. 18. Define adiabatic processes. 19. Describe the differences between theDAR and MAR air masses.20. Describe what happens to a parcel of airas it rises and falls under the influenceof adiabatic processes.42
39Clouds: Clouds are suspended water droplets, ice particles, or a mixture of both.Cloud particles grow around a small tinypiece of solid matter (condensationnucleus) suspended in the atmosphere.Aerosols (condensation nuclei)originate from the ocean.43Droplets of spray are lifted by wind currents, and uponevaporation, the salt xl is left behind to form condensationnuclei – the beginning of a cloud.
40and Convective Precipitation Formation of a Cloudand Convective PrecipitationSaturated air mass risesand reaches the “dewpoint” or LCL (liftingcondensation level)—forming the cloud13Continued rising andcondensation add morewater drops.2LCL124Convection within thecloud suspends waterdroplets.3Water drops grow in sizeovercoming convectiveupdrafts and exit thecloud. This is rain.444
41Condensation! Water vapor rises in the atmosphere 45Condensation!Water vapor rises in the atmosphereand cools (condensing) forming clouds.CondensescoolscoolscoolsLCLVapor risesVapor rises
42Convection inside a cloud “turbulence”46Air cools (sinks)Hot air rises
43Orographic Precipitation Oro (mountains) -moist air moves up and over a mountain barrier.Dry AirPrecipitationRainShadowmoving moistairDry AirSierraNevadaMountainsPrecipitationRain ShadowCoastRangesEvaporationBakersfieldSantaBarbara47
44I to breathe our atmosphere. 48 21. What are condensation nuclei, and whatrole do they play in cloud formation?22.Describe the occurrence of precipitation in boththe convective and orographic environments..
45Clouds are classified based on their height and vertical development. high, middle, or low cloudsvertical extension into the atmosphere49
46Cirrus cloudshigh clouds – white and “wispy”often have a feathery appearanceappear at 20,000 feetcommonly appear in fair weather and pointin the direction of air movement50
47Cumulus clouds globular individual cloud masses contain a flat base (condensation level)rising domes with anvil head topscommonly 1000 feet above the surfacetremendous amounts of energy releasedfrom condensing water vapor51
48very low “cloud sheets” covers wide areas of the surface Stratus cloudsvery low “cloud sheets”covers wide areas of the surfacecan be considered foga low gray blanket of moisturecan bring rain or snow52
49This is the “Don’t be in the clouds before the final exam” formation. 53
50I to breathe our atmosphere. 23. How are clouds classified? 24. Give two examples of cloud types inhigh, middle, and low altitudes.54