I am a Research Scientist at the Institute for Geophysics, Jackson School of Geosciences. I also sometimes teach in the Department of Geological Sciences and at Deep Springs College, California. I received a B.S. in Electrical Engineering from Rice University and then worked for JPL for two years, primarily in Radar Science and Engineering. I then received M.S. and Ph.D. degrees in Geology from Caltech, where I studied geomagnetic field behavior. I returned to JPL as a post-doc, and in 1998 I joined the UTIG cryospheric studies group, acquiring airborne geophysical data in Antarctica including radar sounding of the ice sheet to map subsurface topography and internal layering. This led to Mars analog work in the Dry Valleys of Antarctica, and NASA funding to develop analysis techniques applicable to the orbital radar sounding of Mars. In early 2007 I was selected to be on the Mars Reconnaissance Orbiter Science Team, assigned to the SHARAD radar instrument. Along with my students, I am currently working on the evolution of the northern polar layered deposits, including the spiral troughs and large chasma, through the analysis of detailed, 3-dimensional radar stratigraphy. I am also studying glacial ice in the middle latitudes, preserved under a blanket of rock and dust. All of these features are related to the movement of water ice controlled primarily by climate, presumably with forcing from orbital variations.