Cooperative Institute for Research in Environmental Sciences

ECEE Seminar - Dustin Schroeder

ECEE Seminar - Dustin Schroeder

Using Airborne Radar Sounding to Characterize Subglacial Boundary Conditions

Dustin Schroeder - Jet Propulsion Laboratory, California Institute of Technology

The basal morphology, lithology, and hydrology of ice-sheets and glaciers can exert strong, evendominating, control on their evolution, stability, and sea level contribution. However, the scales at which thephysical processes and observable signatures of this control occur are typically smaller than the spatialresolutions achievable using ice penetrating radar. Further, the strength of calibrated radar bed echo returns is acombination of both the material and geometric properties of the ice/bed interface. This ambiguity in thecontribution of material and geometric bed properties, along with uncertainty in englacial attenuation fromunderconstrained ice temperature and chemistry, also makes definitive assessment of basal conditions fromecho strengths difficult. To address these challenges in interpreting geometric and material bed properties atglaciologically relevant scales, new approaches have been developed that exploit the echo character and spatialpattern of sounding radar bed returns. The application of these techniques to a radar sounding survey ofThwaites Glacier, West Antarctica, shows how the information in the along-track scattering function of the bedcan be used to assess the extent and geometry of distributed water across the catchment and detect the transitionof the water system from distributed canals to concentrated channels. This information can also be used toconstrain the morphology of basal bedforms to infer the distribution of deformable sediments and crystallinebedrock. Finally, models of radar return strength and subglacial water routing can be compared to infer thedistribution of geothermal heat flux and interpret its observed heterogeneity in the context of regionalvolcanism.

Dusty is a Radar Geophysicist and Systems Engineering in the Radar Science and Engineering Sectionat JPL. He earned a PhD in Geophysics from the University of Texas Institute for Geophysics, where he was anNSF Graduate Research Fellow. He received his B.S. in Electrical Engineering and B.A. in Physics withminors in Mathematics and Philosophy from Bucknell University in 2007. At UTIG, he served as the lead RFfield engineer during three three-month Antarctic field seasons with the ICECAP international airbornegeophysical survey of East Antarctica and NASA's Operation Ice Bridge. He has also participated in a range ofprojects, proposal, and working groups for developing radar sounders in support of the JUICE and EuropaClipper missions. Dusty also serves as the Co-Chair of the Earth and Space Science Committee for the NationalScience Olympiad and is the National Event Supervisor for the middle school Astronomy and Planetary Scienceevents.

location

DLC Collaboratory