Albedo: The ability of an object or surface to reflect light and radiation.

Atmosphere-Ocean coupled models: GCMs containing separate atmospheric and oceanic models that can interact and to form a more complete representation of climate.

Climate: the sum total of weather averaged over a long period of time - usually years - and across a large section of the Earth.

Convection: Vertical distribution of heat and energy in the atmosphere. Thunderstorms are a common result of very strong convection.

Dynamic equations: The fluid dynamics equations that govern the atmosphere.

Electronic Numerical Integrator And Computer, or ENIAC : The first electronic, digital computer, used in the late 1940's.

Fast Fourier Transforms: A mathematical algorithm used to help solve complex equations such as partial differential equations.

Grid box: The area in a model where the atmosphere is represented. Data in the grid box is interpolated from the nearby grid points.

Grid points: Imaginary locations in a model where calculations determine variables such as air temperature, humidity, and wind vectors.

Mesoscale models: Numerical models that allow scientists to examine small areas.

Numerical Weather Prediction: Using numerical models to assist forecasters in making weather forecasts.

Parameterization: A technique that modelers employ to replace highly complex climatic processes or processes that occur on too small scales to be fully represented in a GCM by more simple representations.

Radiation balance: The equation that describes incoming solar radiation (short-wave) vs. outgoing (long-wave) radiation emitted by the earth and atmosphere. The balance is currently shifting due to the addition of greenhouse gases to the atmosphere.

Regional scale models: Numerical models that focus on a certain area that is much larger than a local area, but much smaller than the whole globe; these are usually capable of using finer resolution than typical GCMs.

Spectral conversion: Transforming complex mathematical equations to more simple representations as waves.

Time step: The time that passes in a model before the variables are updated. The mechanism that allows the model to propagate through time.

Troposphere: The lowest level of the atmosphere where most of the world's weather occurs.

Weather: Relatively local perturbations in the state of the atmosphere over a relatively short period of time, as opposed to climate, which is the sum total of weather averaged over a long period of time and across a large section of the Earth.