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Air and Surface Temperature. Radiation Receipt. The sun transmits its energy to the Earth through radiation. Solar radiation is received as parallel rays of energy (“line of sight, speed of light”) Radiation—energy (heat) transmitted through electromagnetic waves. Radiation. Radiation Laws.
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Radiation Receipt • The sun transmits its energy to the Earth through radiation. • Solar radiation is received as parallel rays of energy (“line of sight, speed of light”) • Radiation—energy (heat) transmitted through electromagnetic waves
Radiation Laws • All objects emit radiation. • Hot objects emit more radiation (per unit area) than cold objects. more radiation less radiation
Transmission Direct radiation Direct radiation • Energy is passed through the atmosphere • Energy/heat provided to the Earth system
Scattering • Energy “bounces off” particles in the atmosphere. Backscattering (albedo) Scattering (diffuse radiation)
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 • ozone • oxygen • carbon dioxide • water vapor • liquid water / clouds • Energy is absorbed (converted) by the atmosphere or the surface from radiation to heat • Thermal (heat) energy created.
The Greenhouse Effect Water Vapor Carbon Dioxide Methane Greenhouse Gases
The Greenhouse Effect Keeps Earth’s average temperature 35ºC warmer (15ºC now, -20 ºC otherwise) Human role? ‘A heated debate’ Venus 480ºC thick carbon dioxide Mars -62 ºC little carbon dioxide
Conduction Molecule to molecule energy transfer When molecules collide, higher energy molecules excite lower temperature molecules, thereby transferring kinetic (heat) energy.