radiation insolation and energy transfer
Download
Skip this Video
Download Presentation
Radiation, Insolation, and Energy Transfer

Loading in 2 Seconds...

play fullscreen
1 / 25

Radiation, Insolation, and Energy Transfer - PowerPoint PPT Presentation


  • 58 Views
  • Uploaded on

Radiation, Insolation, and Energy Transfer. Solar Radiation: Sun to Earth. Speed of light: 300,000 km/second (186,000 miles/sec.) Distance to Earth: 150 million km (93 million miles) Radiation reaches us in about 8.3 minutes. Radiation.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Radiation, Insolation, and Energy Transfer' - steel-vinson


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
solar radiation sun to earth
Solar Radiation: Sun to Earth
  • Speed of light: 300,000 km/second

(186,000 miles/sec.)

  • Distance to Earth: 150 million km (93 million miles)
  • Radiation reaches us in about 8.3 minutes
radiation
Radiation
  • Radiation: energy transferred in the form of electromagnetic waves
    • no transfer of matter
    • no material medium needed

Solar Constant = 2 calories/cm2/minute

classifying radiation
Classifying Radiation
  • Classified based on wavelength, 
the electromagnetic spectrum
The Electromagnetic Spectrum

Micrometers or microns (µ) = 1/1 000 000 or 0.000 001 or 10-6

Hence Microwaves are about 1mm - long.Radio waves are about a meter to 1000 meters long.

insolation

The sun’s energy distribution:

    • UV and shorter = 7%
    • Visible light = 50%
    • Infrared (IR) = 43%
  • Thermal Infrared, the longest infrared, = heat.
  • Microwaves(1 mm – 30 cm) are used for long distance communications.
  • Radar is portion of microwave. Microwave cooking discovered on Navy ships. Takes 1/2 the energy of conduction or convection ovens - more efficient.
  • Why doesn’t microwave pass through window of oven?
  • Gamma - used for food safety. Discovered after nuclear blasts.
Insolation
radiation laws
Radiation Laws
  • All objects emit radiation.
  • Hot objects emit more radiation (per unit area) than cold objects.

more radiation

less radiation

radiation laws1
Radiation Laws

Sun: 6000ºC (11,000ºF)

Earth: 15ºC (60ºF)

(Wein’s Law) The hotter the radiating body, the shorter the wavelength of maximum radiation.

getting through the atmosphere energy pathways and principles
Getting through the atmosphere:Energy pathways and principles
  • Transmission
  • Scattering
  • Reflection
  • Absorption
  • Refraction
transmission
Transmission

Direct radiation

Direct radiation

  • Energy is passed through the atmosphere
  • Energy/heat provided to the Earth system
scattering
Scattering
  • Energy “bounces off” particles in the atmosphere.

Backscattering (albedo)

Scattering (diffuse radiation)

scattering1

Scattering & light

  • short  , scatter
  • result?
Scattering

Rayleigh Scattering:selective scattering if dust is about 1/10 the wavelength of light (.5 micron)

VIB G YOR 4x 1x

1. sun appears yellow as VIB is scattered out.

2. sky is blue: VIB is down-scattered and becomes prominent.

  • distance , scatter
  • result?

Mie Scattering:white scattering, non-selective, occurs with bigger particles, about 30x the wavelengths of light.

1. salt crystals: things whiter at distance2. bluer sky at high elevation - less white 3. white clouds.

reflection

Albedo ()

  • reflective quality of a surface
Reflection
  • Energy is bounced directly back out to space (energy loss to Earth’s system)

Light color  high 

Dark color  low 

absorption
Absorption
  • ozone
  • oxygen
  • carbon dioxide
  • water vapor
  • liquid water / clouds
  • Energy is absorbed by the atmosphere or the surface
  • Thermal (heat) energy created.
refraction
Refraction
  • Change in direction direction of radiation, by wavelength, in response to change in density of medium.
refraction1
Refraction

Change in direction direction of radiation, by wavelength, in response to change in density of medium.

four heat transfer mechanisms
Four Heat Transfer Mechanisms
  • Conduction
  • Convection
  • Adiabatic Cooling and Warming
  • Latent Heat in Phase Changes of H2O
conduction
Conduction

Molecule to molecule energy transfer

When molecules collide, higher energy molecules excite lower temperature molecules, thereby transferring kinetic (heat) energy.

convection
Convection

Heat is transferred by the movement, from place to place, of a gas or liquid. The principal motion is vertical. All heated gases and liquids experience this kind of “mixing” heat exchange.

adiabatic cooling and warming
Adiabatic Cooling and Warming

When air rises it expands and cools as its pressure is decreased. Thus, when it descends, it is warmed, as pressure increases. This change takes place without the addition or subtraction of energy from another source.

phase changes latent heat
Phase Changes (Latent Heat)

Ice

80 calories/gram

Water

585 calories/gram

Water Vapor

Freezing

Melting

Sublimation

Releases Energy

Stores Energy

Sublimation

Evaporation

Condensation

slide24

100 Units Outgoing

100Units

6Units

30Units

64Units

64Units Longwave

6Units Conduction/Convection

22 Latent Heat

14Units Greenhouse

3 Ozone

19 direct absorb

48Units

key points
Key Points
  • Electromagnetic radiation and spectrum
  • Radiation laws and solar radiation
  • Energy pathways and transfer principles
  • Earth energy budget
ad