UNIVERSITY OF TEXAS AT AUSTIN
The East Antarctic Ice Sheet (EAIS) holds the bulk of Earth's ice. While most of the EAIS is grounded above sea level, significant portions are grounded below sea level and may be sensitive to marine ice sheet instabilities. The Wilkes Subglacial Basin (WSB), which runs north to south inland of the Transantarctic Mountains, is a major region of the EAIS that lies below sea level; recent results from NASA's ICESAT and GRACE satellites suggests increased ice loss in the outlet glaciers along the northern coastal margin of the WSB, that may be due to enhanced ocean melting at the grounding line. In addition, combined results from ICESAT and the Terra satellite's ASTER instrument indicate a different mechanism for changing ice flow is operating in the central WSB. The activity of hydrological systems detected by surface elevation changes has been shown to correlate with accelerations in Byrd Glacier, suggesting time varying basal lubrication linked to these evolving hydrological systems. Attribution of surface elevation changes between enhanced ice flow, changes in surface mass balance and evolving hydrological systems requires high spatial resolution observations of surface elevation change, as well as the subsurface context for these changes. In 2009-2010, our team at UTIG developed a long range airborne platform (a twin turbine Basler DC-3T) hosting an integrated system of radar sounders coupled to a scanning lidar, and gravity and magnetics instrumentation. We successfully sounded the intensely crevassed Byrd Glacier using both ice penetrating radar and gravity, as well as the major glaciers of East Antarctica's Wilkes Land Coast as part of the ICECAP/ICEBRIDGE '09 project. We conducted initial surveys along ICESAT lines both in the Byrd Glacier catchment and along the Wilkes Land Coast. The goals of the ICEBRIDGE/ICECAP 2010-2011 program are to: 1) improve ice thickness and surface elevation baselines over the eastern George V Coast and the David Glacier System; 2) refly surface elevation profiles in the Byrd Glacier system flown in 2009; 3) refly ICEsat 1 surface elevation profiles over the grounding line of Totten Glacier system flown in 2009 and create a denser suite surface elevation profile consistent with ICEsat 2 coverage. 4) collect gravity and magnetic field data to enhance the geological , morphological and bathymetric context for surface elevation change. We will primarily use the US Antarctic Program's facilities at McMurdo to survey the Wilkes Subglacial Basin with support from the French Polar Institute and the Australian Antarctic Division. After the field season we will time synchronize our raw data and turn it over to NSIDC for archiving and distribution in April of each year. Line based observations will be released to NSIDC in May, followed by gridded data in June.