This award supports a project of scientific investigations along two overland traverses in East Antarctica: one going from the Norwegian Troll Station (72deg. S, 2deg. E) to the United States South Pole Station (90deg. S, 0deg. E) in 2007-2008; and a return traverse starting at South Pole Station and ending at Troll Station by a different route in 2008-2009. The project will investigate climate change in East Antarctica, with the goals of understanding climate variability in Dronning Maud Land of East Antarctica on time scales of years to centuries and determining the surface and net mass balance of the ice sheet in this sector to understand its impact on sea level. The project will also investigate the impact of atmospheric and oceanic variability and human activities on the chemical composition of firn and ice in the region, and will revisit areas and sites first explored by traverses in the 1960's, for detection of possible changes and to establish benchmark datasets for future research efforts. In terms of broader impacts, the results of this study will add to understanding of climate variability in East Antarctica and its contribution to global sea level change. The project includes international exchange of graduate students between the institutions involved and international education of undergraduate students through classes taught by the PI's at UNIS in Svalbard. It involves extensive outreach to the general public both in Scandinavia and North America through the press, television, science museums, children's literature, and web sites. Active knowledge sharing and collaboration between pioneers in Antarctic glaciology from Norway and the US, with the international group of scientists and students involved in this project, provide a unique opportunity to explore the changes that half a century have made in climate proxies from East Antarctica, scientific tools, and the culture and people of science. The project is relevant to the International Polar Year (IPY) since it is a genuine collaboration between nations: the scientists involved have complementary expertise, and the logistics involved relies on assets unique to each nation. It is truly an endeavor that neither nation could accomplish alone. This project is a part of the Trans- Antarctic Scientific Traverse Expeditions Ice Divide of East Antarctica (TASTE-IDEA) which is also part of IPY.
Future rates of sea level rise will largely depend on the mass balance of the big polar ice sheets. Like balancing a checkbook, quantifying an ice sheet's mass balance requires that we know how much mass in being added (snowfall) and how much is leaving (melting, icebergs). Much progress has been made recently on quantifying the amount of mass leaving the Antarctic ice sheet in form of icebergs and snow/ice melt. But estimates for the amount of snow being added, and where it is being added, have been very difficult to obtain. There are two reasons to explain this relative lack of progress. One, the ice sheets are large and remote places where it is difficult to work. And two, most measurements of snowfall are derived from point sources such as ice cores, of which there are fewer than 500 reliable sources in all of Antarctica, an area one and half times the size of the continental United States. Extrapolating regional trends from ice cores has proven to be very challenging. As part of this project, we have developed and applied a new method for estimating snowfall rates across Antarctica. It uses both ice cores and ground-penetrating radar profiles obtained along oversnow traverses by tractors. Ice cores allow us to date layers in the upper 100 m of the ice sheet. Using a radar, we are able to track these same layers continuously across hundreds of miles. By transferring ice core ages to the layers in the radar profiles, and by knowing their depth below the surface, we are able to estimate snow accumulation rates at literally tens of thousands of points across the ice sheet. For the first time, we are building reliable maps of snowfall across parts of Antarctica. Ultimately, this work will help us balance the ice sheet's mass gains and losses with greater precision, and provide a firmer basis for predicting future rates of sea level rise.
