Climate Science ATS 201

How does Earth exchange energy with outer space?

Radiation

True or False: Everything with a temperature radiates energy

True

Where does solar radiation peak in the spectrum?

Visible light

What is radiative flux?

The rate that energy flows across a plane

What are the units of radiative flux?

Watts per square meter (W/m²)

When does global mean temperature change occur?

When energy input is different from energy output

What is the inverse square law?

Radiative flux decreases with the square of distance from the source

Inverse square law equation

Flux = Power / (4πr²)

What happens to flux if distance is doubled?

It decreases by a factor of 4

Why does doubling distance reduce flux by a factor of 4?

The surface area over which energy spreads increases by 4

How does solar radiative flux vary among planets?

It decreases with increasing distance from the Sun

What is a blackbody?

An ideal object that absorbs and emits 100% of radiation at all wavelengths

Why are blackbodies important in climate models?

Earth’s emission can be approximated as blackbody radiation

How does temperature affect blackbody radiation wavelength?

Hotter objects emit shorter wavelengths; cooler objects emit longer wavelengths

Which law relates peak wavelength to temperature?

Wien’s Law

Wien’s Law equation

λmax (μm) = 2900 / T (K)

What units must wavelength be in for Wien’s Law?

Microns (μm)

Approximate temperature of the Sun using Wien’s Law

~5800 K

Which law relates emitted flux to temperature?

Stefan-Boltzmann Law

Stefan-Boltzmann Law equation

F = σT⁴

What is the Stefan-Boltzmann constant (σ)?

5.67 × 10⁻⁸ W m⁻² K⁻⁴

Does blackbody size affect emitted flux?

No, flux depends only on temperature

Does blackbody size affect total power emitted?

Yes

If temperature increases from 100 K to 300 K, how does flux change?

Increases by a factor of 81

Which star is hotter: blue or red?

Blue