Antarctic Megadunes: Research Plan
The full research plan included a variety of measurements and monitoring experiments. Even in the harsh working conditions, the team accomplished most of their goals. The aspects of their studies include:
Automated Weather Stations (AWS) and Firn Temperature
During the first field season, Mark Fahenstock of the University of Wisconsin, Madison, placed an AWS at the camp site. The weather data from the first year provided no surprises—the weather is reliably cold and windy.
During the second season, Terry Haran substituted for Fahenstock, deploying two new AWS, one upwind and one downwind of the field camp, that transmit data via satellite back to Fahnestock in New Hampshire. He also refurbished and retrieved 11 months of data from the AWS that Fahenstock had installed the previous year. The three weeks at megadunes camp was barely enough time to get them all set up and running.
The weather stations contain a series of four thermistor strings set into the snow and connected to a data logger. Power to run and warm the AWS recording equipment requires a combination wind-solar-battery system, which was developed for this expedition. The thermistors measure the temperature of snow and firn (a transitional stage between snow and glacial ice). The instruments record data year round.
During the first field season, Mary Albert and Chris Shuman dug snow pits to gather snow samples and data on snow and ice structure. In conjunction with the snow pit, team members drilled two firn cores, 1.9 and 3.8 meters deep. In the laboratory, researchers measure and record the snow and firn layering in cores and preserve samples to examine under the microscope. They also measure the density and permeability profiles according to depth at each site.
For the second field season, Mary Albert's graduate students Zoe Courville and Lawrence "Mac" Cathles from the Cold Regions Research and Engineering Lab (CRREL) took over these responsibilities.
Global Positioning System (GPS) and Ground Penetrating Radar (GPR)
Rob Bauer and Ted Scambos spent many uncomfortable hours on snowmobiles bouncing over the snow pack to set up the radar and Global Positioning Systems (GPS) traverse lines that ranged over an area of 50-55 kilometers. They pulled a shielded Ground Penetrating Radar (GPR) antenna behind the snowmobiles to record data. GPS monitors the movement of dunes and GPR measures accumulation and the structure of underlying ice layers. GPR can provide information on the upper 100 meters (328 feet) of ice, which represents several hundred years of snow accumulation. The GPR allows researchers to look back in time as well as see the structure. A new antenna used during the second season allowed them to investigate the snow layering even deeper, allowing a peek at the structure of the last several millenia. For more information on dunes formation, see How the Dunes Were Formed.
The remote sensing part of the research will include support of the field work and study of the dunes throughout East Antarctica. The following list details some of the measurements from remote sensing:
- Range and limit of dunes
- Cause of dune size and amplitude
- Temperature profile variations
The team hopes to confirm results from field work with results from remote sensing data. They can extrapolate their findings from the study site to the larger area of dune fields.
Elevation Profile From ICESat
Some of the remote sensing data comes from the Ice, Cloud, and land Elevation Satellite (ICESat). For more information on the ICESat project, visit the ICESat Web page. Launched in January 2003, this laser altimeter mission can take precise elevation measurements across the Antarctic ice sheet surface along Antarctic tracks shown the following figure, as well as around the world.
The next figure defines the character of the megadunes in terms of amplitude and spacing of the dune crests/troughs. Note that the horizontal axis is in kilometers, and the vertical axis is in meters. This illustrates that the megadunes are so flat that a large vertical exaggeration (horizontal scale/vertical scale) is needed to show them at all.