Chapter 4 Flashcards
Earth-atmosphere balance
Inputs: UV, visible, near-infared (shortwave)
Outputs: thermal infared (Longwave)
Energy Balance
Its a budget that involves an input/Output, and income/expenditures.
Overall system is…
steady states (locally different)
Transmission
Energy being allowed through the atmosphere or water.
Observed color is due to…
Scattered wavelengths
Scattering
Changing direction of lights movement.
Rayleigh Scattering
Small particles 02, N2 scatter shorter wavelengths (blue/Violet)
Why the sky is blue.
Mie Scattering
Large particles (smoke, dust) scatter longer wavelengths.
Refraction
AS insolation enters the atmosphere, it passes from one medium to another, causing change in speed and direction.
Albedo
Reflective quality of a surface related to color and texture (%)
Light and smooth: High albedo
Dark and rough: Low albedo
Earth 31%
Earth is 4x brighter than the moon
Energy
Capacity to do work, or composition.
Potential
Energy of position or composition
Ex:
Position - reservoir above a dam
Composition - petroleum
Kinetic
Energy of motion
Ex:
Walking
Vibrations of molecules (measure of vibration = temperature)
Heat
A flow of kinetic energy between molecules from one body to another.
(Type of heat) Sensible
Is what you feel.
Temperature is a measure of molecule vibration.
(Type of heat) Latent
Heat due to a change in state.
Substance doesn’t change temperature.
Melting, evaporation, sublimation - absorbs heat
Freezing, condensation, deposition - releases heat
(Heat Transfer) Radiation
Electromagnetic waves
(Heat Transfer) Conduction
Molecule to molecule diffusion.
(Heat Transfer) Convection
Mixing and circulation.
(Heat Transfer) Advection
Directional mass movement.
Greenhouse Effect
Longwave radiation is not trapped like an actual greenhouse.
Atmosphere delays transfer of heat from Earth into spce, and reradiates back to Earth.
Clouds, gases, dust, water vapor, etc can absorb longwave radiation.
Radiation is then re-radiated back to earth/
(Pollutants in the Atmosphere) Cooling due to aerosols like sulfur dioxide from volcanic eruptions.
Increase reflectivity
(Pollutants in the Atmosphere) Some aerosols absorb radiation and reradiate heat back to Earth warming it up.
Black carbon is one of the strongest absorbing aerosols.
Solar energy moves though the atmosphere…
Reflected
Scattered
Absorbed.
Energy Balance by Latitude
direct insolation (high angle)
Consistent Daylight and little seasonal variation, between the tropics - surplus
Sun at low angle, high albedo, no insolation for 6 mouths at poles - deflect
