|
|
|
My palaeoclimatolgy research is currently focussed on two main areas: the qualification and quantification of climatic interpretations derived from climate proxies and how these can be used to critically evaluate the results of climate modelling experiments of the Mesozoic and Cenozoic (Markwick, P.J., et al., 1999); the application of climate model results to examine other issues in geology (such as palaeo-biodiversity, palaeo-biogeography and palaeo-landscape evolution .
|
|
LEFT: The climate space (temperature only) occupied by modern crocodilians. Properly constrained this can then be used to help intepret the climatic significance of fossil crocodilian occurrences (Markwick, 1998)
|
|
|
The climate modelling work is being done in collaboration with Professor Paul Valdes (University of Reading) and has necessitated the development of a comprehensive set of Cretaceous-Tertiary palaeogeographies (Markwick et al., 2000), of which the Maastrichtian (based partly on work done by the Paleogeographic Alas Project at The University of Chicago) is the most complete (Markwick, 2001), and includes detailed bathymetries and palaeo-drainage systems, so essential for the latest coupled ocean-atmosphere experiments being run. By using the geological data to map the spatial distribution of palaeoclimate (the pattern), comparison with model results is greatly facililtated. These models are used to examine the dynamics of palaeoclimate (the process), but they 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.
|
|
RIGHT: Modelled Mean Annual Temperature (MAT) from an atmosphere only experiment using the UGAMP GCM (Markwick et al., 2000)
|
|
|
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.
|
|
LEFT: The modelled climate space (temperature only) occupied by Early Eocene fossil crocodilians based on the results from two different climate models. The diagonal dashed line represents the modern limit of crocodilians in this climate space, which implies that the model may be underestimating the temperatures for those localities below this line (Markwick et al., 2000)
|
|
It is important to appreciate that the geological record is not an impartial witness of the past. Consequently, much of my research has sought to assess and mitigate the potential impact of biases on palaeoclimatic interpretations derived from geologic data; for instance, qualifying absences of climate proxies, due to taphonomic or collection biases, using control groups. This has had practical applications in the design of databases, especially with the advent of Geographic Information Systems (Markwick and Lupia, 2002)
The integration of detailed GIS-based global palaeogeographies (especially as Digital Elevation Models, DEMs), with the latest coupled ocean-atmosphere models, and well constrained geological datasets with which to valid model experiments has major practical applications for better understanding the Earth System. This is the direction of my current independent research and collaborations.
|
|
Additional information on palaeoclimatology, climate proxies, climate modelling and palaeogeography can be found elsewhere on this site.
|
|
