Simple energy balance model of a planet with albedo, ocean, and atmosphere.

This simulation models the stock and flow of energy between a
star, a planet’s surface (primarily its oceans, which are the largest reservoir
of heat), and space.The assumptions governing this model are:

1. The planet absorbs a fraction of the shortwave
radiation arriving from its star, with that fraction given by (1-*A*), where *A* is albedo.

2. The planet radiates longwave infrared radiation
into space, with the amount of radiation into space given by *σΤe*4, where σ is the Stefan-Boltzmann constant and *Te* is the temperature of the effective
radiating level.

3. The atmospheric lapse rate is 6 K/km.

4. If there is an imbalance between shortwave
radiation absorbed and longwave radiation emitted, the imbalance affects the
temperature of the planet. However, it does not do so instantaneously – the imbalance
must heat or cool the mixed layer of the ocean.

5. At the start of the simulation, the planet is
extremely close to equilibrium given its default parameters. If any of these
parameters are changed, the planet will be out of equilibrium, and will have to
adjust.