Geophysical Fluid Dynamics Research Group

University of Alberta

Publications

Funding Profile

Student Supervision

 
 
 
 
 
 
 

 


Research Program

 

The ocean is the regulator of Earth's climate. The world's oceans store an enormous quantity of heat that is redistributed throughout the world via the currents. Because the density of water is about a thousand times larger than the density of air, the ocean has a substantial inertia associated with it compared to the atmosphere. This implies that it takes an enormous quantity of energy to change an existing ocean circulatory pattern as compared to the atmospheric winds. For this reason, one can think of the ocean as the "memory" and "integrator" of past and evolving climate states. Because of the dominant role played by the ocean in climate change, it is vital to understand the long time temporal variability that can occur in ocean dynamics on a planetary scale.

 

Ocean currents can be characterized into two broad groups. The first are the currents that are wind driven. These currents are most intense near the surface of the ocean. Their principal role is to transport warm equatorial waters toward the Polar Regions. The second are the currents that are driven by density contrasts with the surrounding waters. In this latter group are the deep, or abyssal, currents flowing along or near the bottom of the oceans in narrow bands. Their principal role is to transport cold, dense waters produced in the Polar Regions equator ward (and beyond).

                                                                                                                                                                                          

My research group has worked toward understanding the dynamics of these abyssal currents. In particular, we have focused on developing mathematical and computational models to describe the evolution, including the transition to instability and interaction with the surrounding ocean, of these flows. The goal of this research is to better understand the temporal variability of the planetary scale dynamics of the ocean climate system. Our work can be seen as "theoretical" in the sense that we attempt to develop new models to elucidate the most important dynamical balances at play and "process-oriented" in the sense that we attempt to use these models to make concrete predictions about the evolution of these flows. As such, our work is an interdisciplinary blend of physical oceanography, classical applied mathematics and high-performance computational science.

                                                                                                                                                                                          

In the following sequence of four panels, I give an overview of our work on the dynamics of grounded abyssal currents. There is a hyperlink associated with each image that will take you to a jpeg image of a poster on the topic.

 

Overview of the abyssal circulation

Frictional destabilization of abyssal overflows

Baroclinic instability of grounded abyssal currents

Meridional flow of source-driven grounded abyssal currents

 

In the following sequence of three panels, I give an overview of our work on developing a mathematical stability theory for a class of steadily-traveling dipole vortices called modons, the role of dissipation and time-variability in the background flow in the wave-packet dynamics of marginally unstable baroclinic frontal-geostrophic flow, and a modal interpretation for the dissipation-induced destabilization of inviscidly-stable quasi-geostrophic flow, respectively. Again, there is a hyperlink associated with each image that will take you to a jpeg image of a poster on the topic.

 

Spectral properties in modon stability theory

Dissipation and time-variability in baroclinically unstable frontal-geostrophic flow

Dissipation-induced destabilization of inviscidly-stable quasigeostrophic flow


My Erdös number is 3 (Paul Erdös to George Szekeres to Lawrence Mysak to me). Here is my Academic Lineage.