Lesson 4 IT Flashcards
Electromagnetic Radiation
Sun produces energy through nuclear fusion
EM Radiation moves at speed of light
Incoming Solar Radiation, or insolation, is shortwave
Earth is long wave
Radiation
Process where electromagnetic energy is emitted from an object - generally, the hotter, the more radiation, and the shorter the wave
Sun and earth are near perfect radiators - max rad at all wavelengths
Absorption
EMR strikes an object and is assimilated into that object. The electrons in the other object are energized and begin to move and heat up. Dark colors, minerals, soil are good absorbers. Water varies, generally not.
CO2 is, N is not.
Reflection
Object repels, bounces back EM wave.
Albedo - reflectivity of a surface - snow is great at this
Scattering
Gas molecules, particles in the air redirect EM waves. Diffuse radiation - those scatterings hit the earth. Short waves like violet and blue scatter more easily - so sky is blue.
Low angle, passes through more atmosphere, mostly red waves - explains sunrise/sunset.
Transmission
EM waves go right through an object - such as through glass. Water is a good example.
Greenhouse effect
Transmits short wave EM from the sun, doesn’t transmit long wave from the earth out of the atmosphere. Water vapor, CO2.
Conduction
Transfer of heat between objects w/o change in position. Hot thing makes a cool thing hot. Molecules vibrate other molecules.
Convection
Energy transfer through a fluid, like air or water. Molecules change places.
Advection
Horizontal convection
Adiabatic Cooling
Warm air rises, expands, and cools
Adiabatic warming
Cool air condenses, compresses, descends and warms
Latent heat
Exchange on energy in phase change - evaporation, condensation. Release or storage of energy
Angle of Incidence
Angle at which rays hit the earth - noon, direct and 90 degree. A lot of radiation, concentrated.
o degrees, tangent at sunrise/sunset -not much radiation. Large spread
