Radiation PDF

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Summary

Fall 2018 Weather and Climate Society taught by Trenton Ford...

Description

Radiation Shortwave and longwave *When radiation reaches the top of the atmosphere, the atmosphere will reflect/scatter, absorb, or transmit Reflection - radiation makes contact with material in the atmosphere, reflected or scattered in another direction without energy transfer Specular Reflection - light reflected as a beam of equal intensity, like a mirror Diffuse Reflection (Scattering) - light reflected as a large number of weaker beams traveling in many directions without energy transfer Atmospheric Scattering - insolation is diffused and reflected in many different directions Rayleigh Scattering - Performed by individual gas molecules in the atmosphere. Scattered light Non Selective Scattering - performed by water droplets in clouds, reflect all wavelengths of EMR equally. Clouds produce most frequent non selective scattering Absorption - actual energy transfer from one object to another ● Gases, particles, water droplets all absorb certain wavelengths of radiation. The radiation does not interact (warm) the surface ● The atmosphere on average absorbs ~23% of solar insolation Transmission - Passing of incoming solar insolation unobstructed through the atmosphere to Earth's surface ● 7% of insolation reflected by surface, does not interact with surface ● 47% of insolation absorbed by Earth's surface Albedo - percentage of insolation reflected by an object or substance

● Higher albedo - more insulation reflected, less energy absorbed ● White reflects more, black absorbs more Energy Balance - Input and output of energy from the Earth's surface - atmosphere system 1st law of thermodynamics - Energy must be conserved ● Any energy absorbed by Earth's surface will either heat the subsurface or be transferred to the atmosphere ● Insolation absorbed by Earth's surface increases the surface temperature ● If energy is not equalized between surface and atmosphere (hot surface + cold atmosphere) *Earth transferred energy to the atmosphere via conduction, convection, and longwave radiation, equalizing energy balance Convection - energy transferred by the movement of fluid - liquid or gas ● Heat from surface moved upward to the atmosphere through the mixing of air ● Convection moves energy from the surface to the atmosphere through sensible heat and latent heat ● Energy transfer from surface to atmosphere through condensation Sensible heat - transfer of energy that directly affects temperature *latent heat required to convert a solid into a liquid/vapor without a change in temperature...