Let's consider some of the common models of the Earth's atmosphere and how they relate to principles of energy transfer. Some features of these models can help us understand the atmosphere, but it is important to keep in mind their differences from the real atmosphere.
The 'Greenhouse' Model:
A greenhouse maintains a healthy, comfortable temperature by absorbing radiant energy from the sun, emitting infrared energy (heat) and preventing the loss of that heat through convection. The Earth's surface is warmer than the outer atmosphere, just as the inside of a greenhouse is warmer than outside. However, Earth's atmosphere does not 'trap' heat by stopping convection like a greenhouse does. Rather, 'greenhouse gases' in our atmosphere absorb outgoing energy and re-radiate it back towards the Earth, transferring energy to nitrogen and oxygen molecules in our atmosphere, increasing their kinetic energy.
The 'Blanket Model'
A blanket or sleeping bag keeps the wearer warm by preventing convection of the heat energy the wearer produces. This model suggests that the atmosphere acts as a 'blanket of air' that prevents heat loss. Is this a "good enough" model? How is it helpful/accurate, and how is it different from our real atmosphere?