My research is concerned with elements of geophysical fluid mechanics and the role of the ocean in the earth climate system. I make use of theoretical concepts, idealized process physics models, realistic numerical circulation models, and field measurements. Particular research topics include studies of Atlantic and Southern Ocean dynamics; global and regional sea level variability and change; transport of matter and energy by mesoscale and submesoscale eddies; subgrid scale parameterizations of turbulent ocean stirring and mixing; analysis methods aimed at conceptually understanding ocean circulation and transport; and mathematical methods for ocean circulation models.