GCM...

Image Source: NOAA

Topics: Climate Change, Computer Science, Global Warming, Research, STEM, Stochastic Modeling

Whenever news breaks about what Earth's climate is expected to be like decades into the future or how much rainfall various regions around the country or the world are likely to receive, those educated estimates are generated by a global climate model.

But what exactly is a climate model? And how does it work?

At its most basic, a global climate model (GCM) is a computer software program that solves complex equations that mathematically describe how Earth's various systems, processes and cycles work, interact and react under certain conditions. It's math in action.

A global model depends on submodels

Submodels can be broken into two classes: dynamics and physics. Dynamics refers to fluid dynamics. The atmosphere and the ocean are both treated mathematically as fluids. The physics class includes natural processes such as the carbon organic soil respiration cycle and sunlight as it passes though and heats the atmosphere.

Just as Earth's major systems and spheres — the atmosphere, the biosphere, the hydrosphere and the cryosphere — interact with and influence each other, so too must the subprograms in a climate model that represents them. This is accomplished through a technique called coupling, in which scientists develop additional equations and subprograms that knit together divergent submodels. That's what climate researcher Rob Jacob does at the U.S. Department of Energy's (DOE) Argonne National Laboratory.

Argonne National Laboratory:
Scientists compose complex math equations to replicate behaviors of Earth systems
Angela Hardin