1. Energy and the AtmosphereEnergy and the Atmosphere

2. OverviewOverview
 Insolation-AtmosphereInsolation-Atmosphere
InteractionsInteractions
 ScatteringScattering
 RefractionRefraction
 ReflectionReflection
 AbsorptionAbsorption
 Heat TransferHeat Transfer
 ConductionConduction
 ConvectionConvection
 AdvectionAdvection
 Greenhouse EffectGreenhouse Effect
 Energy BalancesEnergy Balances
 Atmospheric Radiation BalanceAtmospheric Radiation Balance
 Surface Energy BudgetSurface Energy Budget

3. Energy BudgetEnergy Budget
 Open Systems model: ShortwaveOpen Systems model: Shortwave
Energy in, Longwave Energy outEnergy in, Longwave Energy out
 The Energy Budget describes whatThe Energy Budget describes what
happens to insolation after it passes thehappens to insolation after it passes the
thermopause, passes through thethermopause, passes through the
atmosphere and reaches the surface.atmosphere and reaches the surface.
 Atmospheric effectsAtmospheric effects
 Ground effectsGround effects

4. Insolation-AtmosphereInsolation-Atmosphere
InteractionInteraction
 Refers to what happens after the interceptedRefers to what happens after the intercepted
solar radiationsolar radiation entersenters the atmospherethe atmosphere
 TransmissionTransmission
 Both short and long wave radiationBoth short and long wave radiation
 As light encounters gas molecules andAs light encounters gas molecules and
particulates in the atmosphere, the pathwayparticulates in the atmosphere, the pathway
that the light follows changesthat the light follows changes
 Diffusion (scattering)Diffusion (scattering)
 RefractionRefraction
 ReflectionReflection
 AbsorptionAbsorption

5. DiffusionDiffusion
 The Sun’s rays are essentially parallelThe Sun’s rays are essentially parallel
as they reach the Earth’s surface.as they reach the Earth’s surface.
 As they encounter various particles inAs they encounter various particles in
the atmosphere, some light rays arethe atmosphere, some light rays are
bounced in all the different directions.bounced in all the different directions.
 Diffusion, or scatteringDiffusion, or scattering
 Some light scattered back into space (7%)Some light scattered back into space (7%)
 Some light scattered to the Earth’s surfaceSome light scattered to the Earth’s surface
(20%)(20%)
 Diffusion increases as sun angleDiffusion increases as sun angle
decreasesdecreases

6. Incoming rays
Scattered raysScattered rays
Gaseous mediumGaseous medium

7. RefractionRefraction
 Occurs when light passes from one mediumOccurs when light passes from one medium
to anotherto another
 From air to water dropletsFrom air to water droplets
 From air masses of varying temperature andFrom air masses of varying temperature and
densitydensity
 Light ray slows and changes directionLight ray slows and changes direction
 Short wavelengths are refracted more than longShort wavelengths are refracted more than long
wavelengthswavelengths
 Breaks light into a spectrum; rainbowsBreaks light into a spectrum; rainbows
 Convection currents in the air (rising hot air)Convection currents in the air (rising hot air)
cause refraction, creating a shimmery distortioncause refraction, creating a shimmery distortion
 miragesmirages

8. Medium 1Medium 1
Medium 2Medium 2
Incoming rays
Refracted raysRefracted rays

11. ReflectionReflection
 Light that bounces off a surfaceLight that bounces off a surface
 AlbedoAlbedo refers to the amount of light reflectedrefers to the amount of light reflected
back to spaceback to space
 31% of incoming sunlight is reflected31% of incoming sunlight is reflected
 21% by clouds21% by clouds
 7% by diffuse scattering7% by diffuse scattering
 3% by the Earth’s surface3% by the Earth’s surface
 Mainly short wave radiationMainly short wave radiation
 Factors that increase albedoFactors that increase albedo
 Light colorLight color
 Smooth surfacesSmooth surfaces
 Low sun angleLow sun angle

12. Medium 1Medium 1
Medium 2Medium 2
Incoming rays
Reflected raysReflected rays

14. AbsorptionAbsorption
 Light that is not part of Earth’s albedoLight that is not part of Earth’s albedo
 Light that is assimilated by matter (69%)Light that is assimilated by matter (69%)
 Ozone in the stratosphere (3%)Ozone in the stratosphere (3%)
 Clouds (3%)Clouds (3%)
 Atmospheric gases and dust (18%)Atmospheric gases and dust (18%)
 Earth’s surface (45%)Earth’s surface (45%)
 Including photosynthesisIncluding photosynthesis
 Causes the matter to increase inCauses the matter to increase in
temperaturetemperature
 short wave energy is converted to long waveshort wave energy is converted to long wave
(infrared)(infrared)
 including respirationincluding respiration

15.  Absorbed heat energy can be transferred inAbsorbed heat energy can be transferred in
the atmospherethe atmosphere
 Heat energy flows from high to low heatHeat energy flows from high to low heat
 conductionconduction
 transfer of heat energy between two objects throughtransfer of heat energy between two objects through
physical contactphysical contact
 Phase changes: Latent heatPhase changes: Latent heat
 convectionconvection
 occurs in mobile media (liquids, gases)occurs in mobile media (liquids, gases)
 currents: molecules near heat source rise (and cool)currents: molecules near heat source rise (and cool)
while cooler molecules fall (and become heated)while cooler molecules fall (and become heated)
 advectionadvection
 similar to convection, but occurs horizontallysimilar to convection, but occurs horizontally
 radiationradiation
 heat transmitted as infrared radiationheat transmitted as infrared radiation

16. Greenhouse EffectGreenhouse Effect
 CloudsClouds
 Are variable in coverAre variable in cover
 Exert tremendous influence on energy budgetExert tremendous influence on energy budget
 Increase albedo (albedo forcing)Increase albedo (albedo forcing)
 Increase greenhouse warming (greenhouse forcing)Increase greenhouse warming (greenhouse forcing)
 Certain gases in clouds absorb and reradiate infrared radiationCertain gases in clouds absorb and reradiate infrared radiation
 Carbon dioxide, water vapor, methaneCarbon dioxide, water vapor, methane
 Creates an insulating effectCreates an insulating effect
 Different cloud types affect the greenhouse effectDifferent cloud types affect the greenhouse effect
differentlydifferently
 High thin clouds allow more diffuse light through, causingHigh thin clouds allow more diffuse light through, causing
more heat to be trapped (net greenhouse forcing)more heat to be trapped (net greenhouse forcing)
 Low thick clouds reflect more light out, causing less heatLow thick clouds reflect more light out, causing less heat
to be trapped (net albedo forcing)to be trapped (net albedo forcing)
 The greenhouse effect has been identified as theThe greenhouse effect has been identified as the
main cause of global warmingmain cause of global warming

19. Energy BalancesEnergy Balances
 AtmosphericAtmospheric
radiationradiation
balancebalance
 SurfaceSurface
radiationradiation
balancebalance

24.  Surface Radiation BalanceSurface Radiation Balance
 Refers to 45% of insolation that reachesRefers to 45% of insolation that reaches
the Earth’s surfacethe Earth’s surface
 Daily PatternDaily Pattern
 Insolation peaks at noonInsolation peaks at noon
 varies seasonally, with maximum on the summervaries seasonally, with maximum on the summer
solsticesolstice
 Absorbing the insolation heats the ground,Absorbing the insolation heats the ground,
which in turn heats the airwhich in turn heats the air
 Maximum air temperature reached between 3-4 pmMaximum air temperature reached between 3-4 pm
 Minimum air temperature reached around dawnMinimum air temperature reached around dawn