A nonlinear dynamical view of general circulation model verification: justification and feasibility
This dissertation was written as part-fulfilment of the degree of Master of Mathematical Modelling of the Environment at the University of East Anglia in 2001.
|Supervisors: || Prof. Grant Bigg (Now at University of Sheffield) |
| || Dr. Adrian Matthews (University of East Anglia) |
The chaotic Lorenz model with a forcing imposed is used to highlight a nonlinear dynamical response of the atmosphere to increased external forcing. This implies a climate change signal where the occupation statistics of the atmospheric flow regimes change. It is argued that General Circulation Model (GCM) verification via a regime analysis is sensible and justifiable.
An Empirical Orthogonal Function (EOF) analysis of a 10-year control run of the UK Meteorological Office GCM is carried out. This reveals maxima in the phase space of the leading two EOFs that correspond to the negative Pacific/North American, the blocked North Atlantic Oscillation, the Arctic Oscillation and the “cold ocean, warm land” patterns. Based on this and a comparison with a similar study of a real climate phase space, it is concluded that the regime verification of GCM is feasible and useful.