Airborne gravity and other geophysical techniques for understanding the lithosphere beneath the West Antarctic Ice Sheet

• Main Authors: Bell, Robin E., Blankenship, Donald D., Hodge, Steven M., Brozena, John M., Behrendt, John C.
• Format: Other/Unknown Material
• Language: unknown
• Published: 1993
• Subjects: 46; Antarctic; West Antarctica; West Antarctic Ice Sheet; Havilland; Antarc*; Antarctica; Ice Sheet
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19930022705

As part of a program entitled Corridor Aerogeophysics of the Southeastern Ross Transect Zone (CASERTZ), an aerogeophysical platform was developed to study the interaction of geological and glaciological processes in West Antarctica. A de Havilland Twin Otter was equipped with an ice-penetrating radar, a proton precession magnetometer, an airborne gravity system, and a laser altimeter. The 60-MHz ice-penetrating radar can recover sub-ice topography with an accuracy of about 10 m through 3 km of comparatively warm West Antarctic ice, while the laser altimeter profiling of the ice surface is accurate to approximately 1 m. The magnetic field observations are accurate to several nT, and the gravity measurements are accurate to better than 3 mGal. The aircraft is navigated by a local radio transponder network, while differential positioning techniques based on the Global Positioning System (GPS) satellites are used for recovering high-resolution horizontal and vertical positions. Attitude information from an inertial navigation system is used to correct the laser altimetry and a digital pressure transducer is used to recover vertical positions and accelerations in the absence of satellite positioning. Continuous base-station observations are made for the differential GPS positioning and the removal of ionospheric noise from the airborne magnetometer measurements.