Numerical models in meteorology

Weather and climate are most often predicted using numerical models.

Starting conditions

Numerical models start from a snapshot of the current atmospheric conditions in the area of interest, from the surface to the upper atmosphere, at points on a three-dimensional grid.

Creating forecasts

A set of atmospheric variables, such as wind speed, temperature, pressure and humidity in each grid box are stored and a set of equations are solved for each grid box to predict the values at that point a short time later.

Forecast lead time

The process of generating the forecast is repeated many times; each time the forecast stepping a few minutes further into the future to produce either a weather forecast for the next few days or a climate prediction for the coming 100 years.

Solving equations

The set of equations which are solved when creating a forecast fall broadly into two categories.

Dynamical

The dynamical core solves the equations of motion for a fluid, on a rotating sphere, to calculate the evolution of the atmospheric flow.

Physical

Alongside the dynamical core, a large number of other physical processes operate to:

  • warm/cool or moisten/dry the atmosphere;
  • form clouds and precipitation;
  • represent both the weather which we experience and the effect of that weather on the evolution of the atmospheric flow.

Last updated: 24 August 2016

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