Electromagnetic Radiation, Energy Budget, and Heat Transfer in Earth's Atmosphere

What gases preferentially scatter shorter blue wavelengths?

Nitrogen and oxygen

Why do we see red sunsets?

Because light travels a greater distance, stripping out the blue wavelengths.

What is the reason for no blue sky on the moon?

There is no atmosphere to scatter light.

What fraction of the sun's radiation that reaches Earth is reflected and scattered back to space?

About ⅓

What fraction of the sun's radiation that reaches Earth is absorbed?

About ⅔

What does albedo measure?

The percent of insolation reflected by a surface.

What is the relationship between albedo and surface color?

Darker surfaces have lower albedo (low reflectivity) and higher absorption of energy.

Give an example of a surface with low albedo.

Blacktop

What is heat a measure of?

Energy transfer between systems.

How does heat differ from temperature?

Heat is the total energy of moving particles, while temperature is the average speed of those particles.

What is radiative energy transfer?

Heat transfer via electromagnetic waves that requires no physical medium.

Provide an example of radiative energy transfer.

Feeling the warmth of a fire without touching it.

What is conductive energy transfer?

Heat transfer through physical contact between objects via molecular collisions.

Provide an example of conductive energy transfer.

Touching a pan after it has been in the oven.

What is convective energy transfer?

Heat transfer by circulation of fluids (gases & liquids).

What is sensible heat transfer?

Increasing the temperature of a fluid and moving it somewhere else.

What is latent heat transfer?

Changing the phase of an object with absorbed energy without changing the temperature.

What type of heat transfer is associated with a pot of boiling water on a stove?

Convection (latent & sensible), conduction, and radiation.

What does net short wave radiation represent?

Short-wave radiation gain minus short-wave radiation loss.

What does a positive value in net short wave radiation indicate?

Energy moving toward the surface.

What does net long wave radiation represent?

Long-wave radiation gain minus long-wave radiation loss.

What does Earth emit and absorb in terms of radiation?

Earth emits long wave radiation and absorbs short wave radiation.

What is latent heat flux?

Energy stored in water vapor as it evaporates.

What is sensible heat flux?

Direct heating of the atmosphere.