Research Interests
Atmospheric and oceanic waves and turbulence - continuing lines of research include work on Kelvin-Helmholtz and Holmboe modes of mixing, especially the process of three dimensionalization in free shear layers, internal waves forced by topography and Rossby waves forced by topography and differential heating.
Geophysical fluid dynamics - a central focus of current activity concerns the issues of "balance" and the stability of the "slow manifold", issues that are being addressed in the context of a search for the spontaneous emission of internal wave radiation in high resolution baroclinic wave life-cycle simulations, using both oceanographic (gulf stream) and atmospheric (jet stream) models.
Physics of the planetary interior - a major line of research continues to consist of work on the mantle convection problem, both from the perspective of a-priori numerical models in which the main issue is the impact of pressure induced phase transitions on the radial mixing length, and from the perspective of theory based upon seismic tomographic imaging of internal mantle density heterogeneity. A cornerstone of this effort continues to be the development and application of detailed viscoelastic models of the glacial isostatic adjustment process directed towards mantle viscosity measurement.
Planetary climate - beginning in the early 1990's the focus of research shifted onto problems related to the evolution of the global climate system from the Late Quaternary into the modern era in which the issue of greenhouse induced global warming has become a central concern internationally. The core of this work initially involved analyses of the problem of global sea level change, including the impact of global warming on the globally averaged rate of sea level rise due to the increase in mean surface temperature. This work was an outgrowth of the development of the theory of global glacial isostatic adjustment which provided for the first time a detailed method whereby the melting of land ice could be mapped directly into a prediction of the space dependent rate of sea level rise. This theory now provides the basic methodology whereby modern tide gauge recordings and satellite based sea surface altimetry (TOPEX/POSEIDON data) may be filtered so as to optimally remove the contamination due to the glaciation and deglaciation of the surface that occurred during the Late Quaternary iceage. There are files for specific tidegauge sites and predictions on a 1x1 degree grid in the datasets section under "Predictions of the rate of RSL rise due to GIA".
The same theory has delivered accurate models of the topography and ice distribution in the deep past that are now employed universally to provide the surface boundary conditions required for the reconstruction of past states of the climate system using modern coupled atmosphere ocean general circulation models (this UofT product is distributed internationally through http://www-lsce.cea.fr/pmip2). Significant contributions are now being made in this area of climate system simulation by the Toronto group using the supercomputer system funded by the Canadian Foundation for Innovation (see publication list for examples).