Note, having moved to a faculty position at Memorial University of Newfoundland, this page is no longer maintained. Please visit my new home page.

I'm a generalist figuring out how to survive in an academic specialist world. Along the way I've travelled from a Ph.D. in Quantum Gravity to a Canada Research Chair in glacial systems modelling, with a stop as an organic farmer. I've also long had an on-going interest in radical social change (with a focus on theatrical media), wilderness sports, and systems design. In these pages you can find an overview of current my research, some thoughts on pedagogy and strategy for social change, and some advice for computer modellers.


Research (how to keep a supercomputer busy)

My general focus is on constraining and understanding the dynamics of glacial cycles. An underlying rationale is to develop and test our understanding of climate change by examining past climate change. This project also offers a challenging case study in the modelling and analysis of a complex physical system. My current work breaks down as follows:

Bayesian calibration of deglaciation model

A current project that I'm excited about is the objective Bayesian calibration of a glacial systems model using a large set of geophysical and geological data in collaboration with Radford Neal in the departments of Statistics and Computer Science at the University of Toronto and Art Dyke at the Geological Survey of Canada. This involves the development of a Neural Network emulator of the glacial systems model to allow adequate sampling of the deglacial history phase space by Markov Chain Monte Carlo methods.

A movie of modelled deglaciation (2.7Mb) for North America shows the topographic and surface velocity chronology of one of the better fitting models from the on-going ensemble calibration. How realistic do you think this chronology is? What aspects of it are unlikely?

Deglacial meltwater drainage history for North America

This project started as an off-shoot of the above Bayesian calibration project to examine meltwater drainage distribution during meltwater pulse 1a. It has exploded into the development of an ensemble based chronology for North American meltwater drainage and lakes levels during the whole deglacial period. It will probably feed back into the Bayesian calibration by incorporating strandline and shoreline-tilt data-bases into the calibration constraint set.

Glacial systems model

Probably the favourite aspect of my work (aside from learning) is model building. The MUN/UofT Glacial Systems model is my baby and continues to undergo development. The core elements are a state-of-the-art thermo-mechanically coupled 3D ice-sheet model and a global visco-elastic bedrock deformation model. Other important components include a bed thermal module, physically-based surface mass-balance modules, sub-glacial till-deformation representations and a 2D (latitude-longitude) non-linear energy-balance climate model. Optional modules can compute high-resolution Semi-Lagrangian tracer tracking and surficial meltwater drainage. I am currently developing a higher order ice-dynamics model that accounts for longitudinal and horizontal shear stresses to improve the representation of ice-streams and ice-shelves.

Asynchronous GCM/glacial model

Ice-sheets are quite sensitive to climate. All past glacial model work has relied on the use of either reduced climate models or parameterized interpolations between at most a few GCM snapshots and present day climate. To better examine the impact and dynamics of ice and climate coupling, I'm working with Guido Vettoretti and Flavio Justino on the asynchronous coupling of the glacial systems model with various general circulation models.

Glacial climate dynamics issues

The above cover the "how" but most important are the questions to be examined (asking the "right" question is one of the most challenging parts of science). The issues and questions that are currently absorbing my attention are the following:

Heinrich events
What initiates such events? What controls their timing? What is happening to the ice sheets during such events? And how do such events transmit an apparently near global signal?
Melt-water pulse 1a
Where did the melt-water come from? What was the dynamical source of such a large and fast ice reduction?
Younger Dryas
What was the dynamical source for the re-organization of oceanic thermohaline cirulation that is believed to be responsible for the Younger Dryas cold interval? Why did melt-water pulse 1a not trigger a similar cold event?
What drove the glacial cycle?
What are the critical feedbacks in the cryosphere and climate system that drive the 100kyr glacial cycles? What was the source of the mid-Pleistocene transition? What is the dynamical role of the carbon cycle in the glacial cycle?
What is the phase space of the glacial climate system?
What is the order of the dynamical system? What other limit cycles and attractors are accessible? What controls the dynamical structure?


Me and my C.V.

As of January, 2007, I have joined the Department of Physics and Physical Oceanography at Memorial University of Newfoundland. Prior to this, I was a Research Associate in W.R. Peltier's group in the Atmospheric Physics group at the University of Toronto. I had been working under the Climate System History and Dynamics project (now newly transformed into the Polar Climate Stability Network ) pretty well since it's inception aside from a 2 year hiatus at the University of Georgia in Athens to facilitate my spouse's academic career. My academic history is encapsulated in my C.V.