Overview
I am a PhD candidate with the Department of Earth and Space Sciences at the University of Washington, in Seattle. I collaborate with members from the glaciology group, the seismology group and the Polar Science Center at the Applied Physics Lab.

My research primarily concerns the transient mechanical response of ice sheets and glaciers to surface meltwater. My field areas include both Greenland and Antarctica. In Greenland, I am integrating space-borne observations with seismic data to construct a observation-based quantitative model of the basal hydraulic system. The recent report [Das & Joughin, 2008] that local speedup events follow drainage from supraglacial lakes through ~1km of ice show that the surface hydrological processes have direct influence on basal processes. My primary goal is to formulate a methodology for constraining the morphology of these drainage systems through impulse tests. In Antarctica, I am using seismic and meteorological data gathered over 3 years to determine any seasonality of calving rates and possible basal sliding of Taylor Glacier, a land terminating polar glacier in the Dry Valleys. The dry environment, isolation of the subglacial hydraulic system and small size of Taylor constitute a natural control for more dynamic glacial conditions. My continuing work with Taylor is devoted to characterizing waveforms clusters as precursors to calving or high melt production.

In each component of my research, I use and develop mathematical and signal processing methods from convex set projections to regular perturbation theory as guide to physical interpretation of observations.

My Greenland research is currently supported by the NESSF NASA fellowship program.

My Background
I graduated Magna Cum Laude from Washington State University in May 2004 with a B.S. in physics. My focus as an undergraduate was in shock wave propagation in novel alloys at the Institute for Shock Physics. I spent my first year at UW in the Applied Mathematics department where I obtained a Masters degree. In 2005 I entered the Geophysics program, where I have worked on several seismic field experiments, including the CAFÉ experiment, and the Ice Cliffs project in the Dry Valleys of Antarctica.

Aside from science and math, I enjoy spending time with valued friends, some outdoor recreation, and seeing local punk, rock, and folk shows.

Additional Information and Tutorials
The Quick Links at the top of my site provide links concerning more details of my research, tutorial papers, presentations, and Matlab code to download:

• A tutorial paper on nonlinear inversion (with a Geophysical example)
• A tutorial paper on regularized inversion, via convex set constraint; in this paper I derive the projector when one model parameter is constrained to a part of solution space.
• A tutorial paper on deriving the resonance frequencies of fluid filled conduit
• A paper on the linearized theory of subglacial drainage systems
• Some results on the summer seismicity of Taylor Glacier, ANT
• Some simple results on a method I developed generalizing matching pursuit to using a 'dictionary' of convex cones
• Some old teaching materials on ESS 202, an Introduction to Earthquakes, taught here at the University of Washington

Some materials are old, but if you are sincerely interested in some of my work, do contact me.

Last Up-dated, 04/2009

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