Norwegian-U.S. Scientific IPY Traverse of East Antarctica (2007-2009) (IPY Traverse)

Joint Norwegian - U.S. scientific ground traverse in East Antarctica. The field expedition involved scientific investigations along two overland traverses: one going from the Troll Station in Dronning Maud Land to Amundsen-Scott South Pole Station in 2007-2008; and a return traverse by a different route in 2008-2009. Data were collected for investigations of climate change, with the following goals: 1. Investigate climate variability in Dronning Maud Land of East Antarctica on time scales of years to a million years. 2. Establish spatial and temporal variability in snow accumulation over this area of Antarctica to understand its impact on sea level. 3. Investigate the impact of atmospheric and oceanic variability on the chemical composition of firn and ice in the region. 4. Revisit areas and sites first explored by traverses in the 1960s, for detection of possible changes and to establish benchmark data sets for future research efforts.

Global sea level is modulated by ice sheet mass balance through two competing processes: the addition of mass through the long-term storage of precipitation falling as snow, and the removal of mass through the slower release of water back into the ocean by ice flow which results in melting and iceberg calving along the edges of the ice sheet. Climate variability has an effect on both processes. The longer-term effect relates to ice flow. A much shorter-term fluctuation in ice sheet mass (and volume) occurs when there is a change in accumulation rate. This short-term response is relevant to investigations of present-day sea level rise, as discussed by the 2007 IPCC report. In other words, the Antarctic ice sheet might be undergoing a long-term decrease in volume as the ice flow adjusts to climate change at the end of the last ice age, superimposed on a short-term increase in volume due to recent changes in accumulation rate. The net effect of these two responses is incompletely known, and improving our understanding is a key objective of this project.