Global Atmospheric Model
The ECMWF Atmospheric Global Circulation model describes the dynamical evolution of the atmosphere worldwide on the resolved scale and is used for medium-range, extended medium-range, and seasonal forecasts. It is a general atmospheric model of uniform model physics and structure. It is executed on a global scale at several resolutions each appropriate to the forecast period. The model uses the most accurate estimate of the current conditions and the most up-to-date description of the model physics. It employs throughout modelled land surface conditions (e.g. snow cover, soil moisture), ocean conditions (e.g. sea-surface temperature, sea ice). Also included is a representation of the stratosphere and atmospheric dynamical processes. These together help deliver Rossby wave propagation, weather regime changes, etc..).
However, a single execution of the model does not give definitive results so an ensemble of perturbed runs are also generated. The members of the ensemble are designed to represent the impact that changes to the initial conditions and physical parameterisations - which are both commensurate in magnitude with what we believe to be possible truths - would actually have on the atmospheric evolution. This enables assessment of the uncertainty in the forecast, and also gives an indication of the predictability of the future evolution of weather systems.
Overview
Content Tools