Summaries of US ITASE Projects
Phase 2 (2006 - 2009)

(Phase 1 projects)

US ITASE Glaciochemistry

Principle Investigators

This project undertakes glaciochemical investigations of the Ross Sea Embayment Drainage System, and portions of Wilkes Land for purposes of understanding annual to multi–centennial scale climate variability.  The glaciochemical data that will be collected will contribute to the U.S. component of the International Trans–Antarctic Scientific Expedition and will occur over a period of two years on an overland traverse that will begin at Taylor Dome in Northern Victoria Land and travel to the South Pole.  These data, along with similar information collected on a series of earlier traverses in West Antarctica, will contribute to providing an in–depth understanding of natural climate variability and will provide a baseline for assessing modern climate variability in the context of human activity; and a contribution to the prediction of future climate variability. By choosing appropriate sites for sampling, the traverse will make important contributions to the understanding of the behavior of major atmospheric phenomena such as the Antarctic Oscillation, ENSO, and changes in the chemical composition of the atmosphere, plus controls on all of these changes. US ITASE research addresses important questions concerning the role of Antarctica in global change and will make an important contribution to IPY.

US ITASE Science Management Office

Principle Investigators

The science management office (SMO) acts as coordinator for a series of collaborative science proposals that are part of the U.S. contribution to the International Trans-Antarctic Scientific Expedition (US ITASE). It supports the science administration and the coordination of logistics needed in order to accomplish the research.  The SMO will work with the Antarctic support contractor to coordinate field operations for the traverse platform so that US ITASE can undertake a series of scientific traverses in the region from Taylor Dome, in Northern Victoria Land to South Pole (NVL-SP) inclusive of interior portions of the East Antarctic plateau such as Dome A. US ITASE is the terrestrial equivalent of a polar research vessel. It offers the ground-based opportunities of traditional style over-snow travel coupled with the modern technology of GPS navigation, crevasse detecting radar, satellite communications, and multi-disciplinary research.

Mass Balance and Accumulation Rate Along US ITASE Routes

Principle Investigator

This project seeks to determine the mass balance and accumulation rate of ice along the traverse routes of the U.S. International Trans-Antarctic Scientific Expedition (US ITASE) program. The rate of ice sheet thickening or thinning will be measured along flow lines, along ice divides and along elevation contours in West Antarctica using a method which measures the vertical velocities of markers buried in subsurface ice. This method uses the Global Positioning System (GPS) and surveying techniques to determine the precise location of these markers. Vertical velocities so obtained are compared with long–term rates of snow accumulation and the difference in the two is a measure of ice sheet thickness change. A series of recording instruments will be installed to provide continuous records of firn densification and snow surface elevation change. These instruments will be deployed at selected sites to link transient changes in snow surface elevation, as measured by altimeters, to long-term rates of ice thickness change. Ice motion at drill sites, upglacier topography and upglacier gradients in accumulation rate will be measured and used to calculate ice flow-induced accumulation rate variations and remove them from the ice core records. This work will provide the capability to deduce true past climatic variations in accumulation rate from the US ITASE ice core records.

Radar Studies of Internal Stratigraphy and Bedrock Topography along the US ITASE Traverse

Principle Investigators

This is program of radar studies of internal stratigraphy and bedrock topography along the traverses for the U.S. component of the International Trans-Antarctic Scientific Expedition (US ITASE). The radar will provide information immediately available in the field on ice thickness and internal layer structure to help in the selection of core sites as the traverse proceeds. These data will also be useful in siting deeper millennial scale cores planned at less frequent intervals along the traverse. In addition to continuous coverage along the traverse route, more detailed studies on a grid surrounding each of the core locations will be made to better characterize accumulation and bedrock topography in each area. This proposal is complimentary to the one submitted by the Cold Regions Research and Engineering Laboratory (CRREL), which proposes a high frequency radar to examine the shallower portion of the record down to approximately 60 meters, including the presence of near-surface crevasses. The radar proposed herein is most sensitive at depths below 60 meters and can depict deep bedrock and internal layers to a substantial fraction of the ice thickness.

Stable Isotope Studies at West Antarctic ITASE Sites

Principle Investigator

We propose to obtain stable isotope profiles from shallow (<100 m) ice cores from East Antarctica, to add to the growing database of environmental proxy data collected under the auspices of the “ITASE” (International Transantarctic Scientific Expedition) program. ITASE has the overall objective of improving our understanding of Antarctic environmental change through comprehensive mapping of the ice sheet, with emphasis on climate change and climate variability in the most recent several hundred years. Our contributions to this effort are high resolution stable isotope records, and the use of these records to develop reliable estimates of Antarctic climate change covering the last ~200 years.

The Physical Properties of the US ITASE Ice Cores

Principle Investigator

Ian Baker
Professor of Engineering
Senior Associate Dean, Academic Affairs
Thayer School of Engineering
Dartmouth College
8000 Cummings Hall
Hanover, NH 03755-8000

Objectives

1. Stratigraphic analysis including accumulation rates, annual layers, depth hoar, ice and wind crusts.
2. Rates of grain growth with depth and firn densification rates and how these parameters relate to the meteorology and climatology over the last 200 years of snow accumulation in Antarctica.
3. Determination of seasonality of accumulation by coregistration of stratigraphy and chemistry.
4. Determination of chemical species at the grain boundaries, how these may change with depth/densification (and therefore temperature), precipitation and may affect grain growth.

Satellite–based mapping of Antarctic firn physical properties

Principle Investigator

Thomas A. Neumann
Research Associate
Department of Geology
University of Vermont
Burlington, VT 05405

We propose to improve understanding of the relationship between firn properties and satellite observations at varying frequencies by conducting detailed field measurements across a section of East Antarctica. Specifically, we will target four to six 25 x 25 km study areas chosen to be co–registered with satellite observations, and determine the spatial distribution of relevant firn properties within these areas. We will instrument the primary study areas to obtain vertical temperature profiles, and will measure grain size, density, firn microstructure, permeability and porosity in shallow snow pits. Work to date suggests that snow accumulation rate will be a particularly important influence on these properties, we will also determine accumulation rates with the use of well–dated firn cores and by using high–frequency radar observations in multiple transects across these study areas. Further, we will take advantage of the proposed US ITASE logistics platform (which is coordinating our logistics) to link these study areas with additional ground–truth observations and radar profiles along continuous transects of many hundreds of kilometers. Finally, we will use combinations of satellite observations in different infrared and microwave frequencies to independently deduce firn properties for these areas, through theoretical relationships with firn emissivity and thermal diffusivity. Comparison between the satellite–based and ground–truth results will allow us to validate and refine the theory.