This is the basic agriculture model for students in Project Guts, Fall 2015. This model sets the albedo to the terrain color. The sun emits solar radiation (yellow circles) which travel down to the Earth's surface. Once they collide with the Earth's surface, some of the radiation is reflected while another portion is absorbed and then emitted as infra-red radiation (referred to as "heat" here, represented by red circles). The portion reflected and absorbed is determined by the albedo of the different colors of the terrain (crops, bare ground, city). The more solar energy reflected, the less heat is created.