Geophysical Exploration and Climate Change Research in Antarctica

Initial results from the 2006-07 US-ITASE traverse

Brian Welch
Physics Department
St. Olaf College

The Antarctic ice sheet contains the best-preserved record of the Earth's climate prior to the instrumented era of the last 100 years. The International Trans-Antarctic Scientific Expedition is a cooperative effort by more than 20 countries to extract a continent-scale record of climate change in Antarctica from shallow ice cores and geophysical observations. The U.S. contribution to the program has been to collect ice cores and other supporting data throughout much of the West Antarctic Ice Sheet, focusing on the ice draining into the Ross Ice Shelf . We are continuing that effort by completing the East Antarctic portion of the Ross Ice Shelf drainage basin.

St. Olaf College participates in the US-ITASE program in the unique role of a geophysical exploration program. We specialize in using a low-frequency radar system (built here on campus) to map the bedrock surface beneath the ice sheet as well as the stratigraphic horizons within the ice itself. Thermal conditions at the ice-bedrock interface govern the rate of ice flow and the sensitivity of the ice sheet to changes in boundary conditions (e.g. sea level, temperature, precipitation, etc.). The ice may slide along its base if the ice sheet is at the pressure-melting point and liquid water is present. Past changes in snowfall deposition or wind erosion or changes in local ice flow are preserved within the internal ice stratigraphy and give us clues about past conditions on the continent.

This talk will present an introduction to the US-ITASE program, including some past results from West Antarctica, and then introduce the new traverse route in East Antarctica that will culminate next winter with our arrival at South Pole. Finally, some preliminary results from this year's traverse will be presented. Photos of working in Antarctica will be shown throughout the presentation.