Colloquium: August 4, 2015

Bipolar Science: 20+ Years of Airborne Ice Measurements with NASA and Operation IceBridge

John G. Sonntag

Tuesday, August 4, 2015 at 2:00 P.M. in Pearl Young Theatre in the Integrated Services Building
(video) within the Langley firewall only


NASA began large-scale airborne measurements of Arctic ice in 1993, at a time when little was known about the changes taking place there. Seven years later, this continued effort yielded the first-ever mass-balance assessment of a major ice sheet, showing that Greenland was losing ice to the ocean faster than it was being replenished by snowfall. The pattern of the mass-balance was also striking, showing fast thinning for the low-elevation portions of the ice sheet, transitioning to slow thickening at the highest elevations. The next decade saw a focusing of the airborne measurements on the fast-thinning margins of Greenland’s ice, the first small-scale efforts to address Antarctic ice measurements from aircraft, the launch of the IceSat-1, GRACE, and CryoSat-2 spacecraft, and the first expansion of the airborne effort to include measurements of sea ice thickness. 2009 saw a vast expansion of NASA’s airborne polar efforts with the inception of Operation IceBridge, which deploys large aircraft with state of the art instrument packages to north and south every year, and which continues into the present. This presentation traces the history of these efforts and some of the science output from them, discussing the often similar, but sometimes dissimilar, behavior of the Arctic and Antarctic ice masses. We also discuss the technology behind these discoveries, including the remote-sensing technologies deployed aboard NASA aircraft and other supporting technologies, including novel precise navigation techniques used to guide the aircraft over sometimes featureless landscapes with unprecedented precision. We illustrate the presentation throughout with still and video examples of the breathtaking polar landscapes through which we fly, usually at low altitude, and often with dramatic terrain rising above the aircraft itself on both sides.


John Sonntag was born and raised in north Texas. He received a BS in Aerospace Engineering from Texas A&M University in 1991. He received a MS in Aerospace Engineering from the University of Texas in 1993, after conducting thesis research in the then-emerging fields of Global Positioning System theory and GPS-based geodesy. After graduate school, he took a job with a predecessor organization of AECOM Corporation as a data analyst with NASA’s Airborne Topographic Mapper (ATM) team, as it was beginning large-scale Greenland ice-mapping efforts. 22 years later, John remains a member of the ATM team as a Senior Research and Development Scientist, and also acts as the flight planner and Field Team Leader of NASA’s Operation IceBridge. John has accumulated more than 8000 flight hours as a scientist flying aboard NASA airborne science missions, most of it in the polar regions. He deploys approximately 5 months of every year for IceBridge science, split between Arctic and Antarctic deployments.