Energy Balance Models - General [6 marks] (a) Describe the basic idea behind any energy balance model.

hello, im having trouble understanding the energy balance model. 1. Energy Balance Models - General [6 marks] (a) Describe the basic idea behind any energy balance model. What is the variable calculated in an energy balance model? (b) What are the two main components of the energy balance at the top of Earth's atmosphere (that is, above planetary effects such as clouds and ozone)? Name the two main characteristics of the Earth system that affect them? That is a question on the assignment and i'm wondering what the variable is? Is it not simply just the surface temperature of earth. Also I don't understand the model entirely.. please help