Research

Current Research

The climate community has begun to use and evaluate the skill of general circulation models (GCMs) to predict trends from seasonal to decadal time scales. As part of the Canadian Sea Ice and Snow Evolution (CanSISE) Network, I am evaluating the performance of the Canadian Seasonal to Interannual Prediction System (CanSIPS) on snow related variables using a suite of historical forecasts.

Because the climate system has a large amount of natural variability, even on time scales of years to decades, it's important to compare observed trends to large ensembles of simulations in evaluating whether or not the two are consistent with one another. We have performed this analysis for 80 realizations of the Community Climate System Model (CCSM4) from the National Center for Atmospheric Research (NCAR). Half of the realizations have a freely evolving ocean that interacts with the atmosphere and other model components and half of the realizations are forced with historical values of sea surface temperatures and sea ice. The results suggest that natural variability due to climate noise as well as the historical evolution of sea surface temperatures in the Noth Pacific ocean have played roughly equal roles on the trends in snow cover and snow water equivalent over the last 30 years.

Previous Research

A previous topic of my current research was on better understanding and diagnosing the coupling which occurs in the atmosphere between the bottom weather layer, the troposphere, and the stable overlying layer, the stratosphere. It's currently unresolved how much of an influence the overlying stratosphere would be able to exert (if any) on the troposphere, however there are observations which suggest that the dynamics between the two are coupled.

Listed below are a selection of previous projects on which I've worked. They range from parts of my Ph.D. thesis to more "fun-type" projects. More information can be found by clicking on the accompanying pictures.

I have performed research on the interactions between the gas-disks and protoplanets that are thought to exist in early solar systems. Such systems can be described by the Euler equations on a cylindrical grid. I have developed my own code to solve these equations based on a TVD (Total Variation Diminishing) algorithm. The code is able to capture high Reynolds number flow thus allowing less-smooth interactions to be seen such as asymmetric clearing of gas around the planet.

I have also studied planet ejection from binary systems. Planets that are members of binary star systems experience gravitational tugs from both stars of the system (for reference, roughly half the stars in our sun's local neighborhood are in binary systems). These gravitational tugs will eject the planet from the system unless the planet hugs close enough to one of the stars or alternatively if it remains far enough away from both stars. This project examined the physical mechanisms for the ejection of planets when the first condition does not hold.

During my Master's Degree at the University of Toronto, I worked with Doug Johnstone examining star formation scenarios. We used submillimeter observations of density clumps found in the nearby star forming regions of Rho Ophiuchus and Orion to postulate different scenarios for the collapse of the observed clumps into stars.

Work and results from a mathematics laboratory(!) at the University of Alberta where internal gravity waves were generated using sinusoidal topography in a water tank. The generation of such waves models the actual flow of air over mountain ranges. These waves propagate upwards through our atmosphere until they break at higher altitudes depositing their momentum and thereby affecting the background flow at those levels.

It's possible to model planet surfaces as fractal objects using Brownian motion. Linked here is a brief interactive introduction to Brownian Motion/Noise and Fractals as well a method used to render fractal surfaces of "Earths". This demo was put together by myself and a fellow student for the 1998 Canadian Undergraduate Physics Conference.