Energy Budget of the Earth-Atmosphere System

Energy Transfer

• Conduction -- direct molecular transfer

• Convection -- fluids; air or water– Sensible heat (temperature)– Latent heat (evaporation/condensation)

• Radiation -- no transfer medium

Adiabatic Processes

Energy associated with phase changes

Global Energy Balance

Inputs = Outputs

The Sunspot Cycle

As the distance from the Sun increases, the intensity of the

radiation diminishes in proportionto the distance squared (inverse square law).

The solar constant is the amount of solar energy received by a surfaceperpendicular to the incoming rays at the mean Earth–Sun distance

and is equal to 1367 W/m2.

Radiation Laws

Stefan-Boltzmann Law

E = sigma T (4th power)

Wien's Law:

Wavlength Max - inversely proportional to the temperature

Incoming solar radiation available is subject to a number of processes as it passes through the atmosphere. The clouds and gases of the

atmosphere reflect 19 and 6 units, respectively, of insolation back tospace. The atmosphere absorbs another 25 units. Only half of the insolation available at the top of the atmosphere actually reachesthe surface, of which another 5 units are reflected back to space.

The net solar radiation absorbed by the surface is 45 units.