1 / 14

Lab 4 Outline

Lab 4 Outline. This lab we’ll talk about the energy budget on the earth’s surface. 1. Some radiation laws: Stephan-Boltzmann law (amount) and Wien’s law-(character, i.e., wavelength).

suki
Télécharger la présentation

Lab 4 Outline

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lab 4 Outline • This lab we’ll talk about the energy budget on the earth’s surface. • 1. Some radiation laws: Stephan-Boltzmann law (amount) and Wien’s law-(character, i.e., wavelength). • 2. Some factors of radiation fluxes, i.e., solar and terrestrial in-coming and outgoing radiation (e.g. albedo). • 3. Some basic surface energy budget calculations using net surface radiation formula. • 4. Radiation and season, time of day, cloudiness, etc.

  2. The Surface Energy Budget • Surface energy budget: how much energy is coming to the earth versus going out. • Radiation: mechanism of heat transfer w/out a medium (unlike conduction and convection). • Recall some solar radiation receipt factors: • Seasonal • Diurnal (daily) • Meteorological influences

  3. Three types of heat transfer: • Conduction – requires a medium in which to travel • Convection – requires a medium in which to travel • Radiation – the only mechanism of heat transfer that travels through space. The sun is the ultimate source of energy that drives all our weather.

  4. Radiation Laws - Amount • Stefan-Boltzmann law: • Total energy EMITTED by a body is proportional to temperature 6000 K The warmer the surface, the more radiation is emitted. 300 K

  5. The Surface Energy Budget • The Earth: • Surface temperature = 288K (15°C)

  6. 5.67 x 10-8 = 0.0000000567 2554 = 4,228,000,000 E = 5.67 Wm-2 x 42.28

  7. Radiation Laws: Character • Wien’s law: • Radiation wavelength is inversely proportional to T° Wien’s constant • C = 2898ϻmK • T K Warmer temps = shorterwavelengths

  8. Sun’s wavelength falls under the visible spectrum….which explains the glow we always see around it. • Earth’s wavelength falls under the thermal infared spectrum.

  9. Radiation Fluxes • Radiation budget is made up of the four fluxes • Net surface radiation = SW↓ - SW↑ + LW↓ - LW↑ • Note: SW only a factor while the sun in out Depends on location, time of year, time of day, cloudiness, etc. SW LW SW LW Depends on surface temperature. Depends on the state of the atmosphere. Depends on surface albedo.

  10. SW radiation fluxes only relevant between sunrise and sunset • LW radiation fluxes occur throughout the entire day • LW↑ will always be greater/higher than LW↓; • SW↓ will always be greater/higher than SW↑; some of the incoming radiation will always be absorbed by the earth, reducing the amount that is re-emitted.

  11. Albedo – outgoing sw factor • Light colors reflect more than dark colors. • dark colors have a LOW albedo…they only reflect 10-15% of the radiation (they absorb 20-85%) • light colors have a HIGH albedo…they reflect 50-90% of the radiation (they absorb 10-50%)

  12. The Surface Energy Budget before **Diagram is of an equinox

  13. SW solar radiationLW terrestrial radiation Cloudy skies = lower SW Clear skies = higher SW

More Related