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Climate modelling includes a variety of different approaches, including semi-quantitative (conceptual) models (e.g. those of Parrish or Ziegler et al), Energy Balance Models and General Circulation Models (GCMs). It is with the latter that I am primarily interested, for the simple reason that they have a global coverage and produce a varity of results that can be tested quantatively against observations. It may seem to many that there is something mysterious and suspicous about climate models, and certainly palaeoclimate modelling has generated much controversy over the years. Climate models provide the only means of fully investigating the dynamics (the process) responsible for changing climate (as recorded in the rock record), and for extending that climate beyond the preserved geology. But models do not generate data in themselves; they are hypotheses to be tested against observations, which for palaeoclimate are represented by the geological record, and only the geological record. The goal is to seek convergence between geological data and model results--since these models are also instrumental in predicting the potential direction and nature of future climates, whether naturally or anthropogenically induced, studies of the climate of the geological past have a direct application to present concerns.
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LEFT: General Circulation Models (GCMs) break the Earth's atmosphere, surface and oceans into a series of cells. Boundary conditions, including palaeotopography and bathymetry, and usually atmospheric chemistry (including carbon dioxide concentrations), are important criteria that need to be defined.
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| RIGHT: Typical model output, in this case Maastrichtian Mean Annual Temperature (MAT). The correctness (or otherwise) of such results can only be determined through comparison with well constrained observations (see climate proxies section).
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A number of modelling experiments have been made in collaboration with Professor Paul Valdes, including a series of Maastrichtian coupled ocean-atmosphere runs that are currently been written up. Once this work is published I'll add more information and figures to this page.
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