Models and simulations
The Origins of Climate Modeling
Modeling for weather forecasting has been carried out ever since computer science developed after the second world war. However there are some important differences between modeling for climate and modeling for weather.
Weather models and Climate models
Weather forecasting aims to predict specific weather events in the short term whereas climate modeling aims to understand longer term climate-shaping factors such as greenhouse gases, aerosols and solar variations. As the vagaries of weather and its extremes tend to average out over years or decades, climate models seek to smooth out these exceptional events so as to find the underlying trend. Because of this different objective, climate models lack precision in their short-term predictions over time and specific geographical areas.
Many factors influence weather. Some of them change rapidly over a short period of time such as clouds, wind, moisture, temperature, pressure but others evolve over a longer period of time such as vegetation growth, ice, atmospheric composition, ocean temperature. Weather models tend to consider only the short term factors whereas climate models must incorporate factors whose influence may only be evident over years.
How models Work?
Although global climate models are still far from perfect, much progress has been made in recent years. More factors in more detail have been incorporated into the models so that the models reflect more accurately how the earth system functions.
Models represent the earth with an imaginary grid covering the surface of the earth but also plumbing the depths of the oceans and extending upwards into the atmosphere. Each three- dimensional rectangle of the grid attempts of describe in the form of mathematical equations how several variables feed into the reaction by the Earth to solar heating.
The reliability of models
Model outcomes are then tested for validity against observations. If a model can correctly reproduce past situations then it can be trusted to predict the future. Models are also checked against each other to see if they produce similar results. Some factors are more variable and difficult to predict than others. The interaction of clouds and aerosols with the earth system remains complex but progress is being made every year.
Next: Data compared with models and simulationsBack to Data integration
