Looking at two diagrams below, they seem to depict the same system. How are they different? Why one is a radiation balance model and the other a global energy balance model?
1 Answer
Radiation balance only account for energy transfers trough electromagnetic radiation. Something very useful for the Earth as a whole. As it is the only (or most important by far) way of energy exchange between the Earth and the outer space.
Energy balance in the other hand, account for energy transfers trough all possible processes, namely radiation, conduction, sensible heat, latent heat, convection, etc. That are very important to account for the energy transfers within the atmosphere and between it and the surface.
In this case your global energy balance includes evaporation and convection (thermals), that are forms of energy exchange not mediated by electromagnetic radiation.