General circulation model, GCM

The research published in this book uses the presently most comprehensive multicompartment model, the first which comprises a coupled atmosphere-ocean general circulation model (GCM). GCMs are the state-of-the-art tools used in climate research. The study is on the marine and total environmental distribution and fate of two chemicals, an obsolete pesticide (DDT) and an emerging contaminant (perflu-orinated compound) and contains the first description of a whole historic cycle of an anthropogenic substance, i.e. from the introduction into the environment until its fading beyond phase-out. 

The main tools used to provide global projections of future climate are general circulation models (GCMs). These are mathematical models based on fundamental physical laws and thus constitute dynamical representations of the climate system. Computational constraints impose a limitation on the resolution that it is possible to realise with such models, and so some unresolved processes are parameterised within the models. This includes many key processes that control climate sensitivity such as clouds, vegetation and oceanic convection [19] of which scientific understanding is still incomplete. 

A few studies of the impacts of changes in tropospheric ozone have been based on general circulation models (GCMs Hansen et ah, 1997b, Chalita et ah, 1996). In these studies ozone distributions were taken from CTMs, namely the MOGUNT1A and the IMAGES 3D CTM respectively. 

Three-dimensional models which provide solutions to some form of the primitive equations outlined in Section 3.3 are called general circulation models (GCMs). These models can provide insight on the coupling between dynamical and radiative processes in the atmosphere. They resolve large-scale waves and synoptic eddies, and include state-of-the-... 

General-circulation models (GCMs) attempt to duplicate the distribution of wind as well as of temperature and moisture. They are usually three dimensional however, the earliest models had little resolution in the vertical for example, the pioneering model by Norman Phillips in 1956 consisted of only two layers. In the meantime, much more complete models have been developed, many requiring the fastest computers available. 

The potential of numerical weather prediction technique to study the chmate of the atmosphere was recognized in early days of numerical weather prediction when Norman A. PhiUips succeeded in 1956 an extended time integration of a two-level quasi-geostrophic model, starting fiom an atmosphere at rest. He demonstrated that marty features of the general circulation of the atmosphere could be simulated by the model. Since then mar general circulation models (GCMs) have been started to develop based on the primitive-eqrration model formrrlation (Sec-... 

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