On May 1, a team of five researchers from Boise State University and Dartmouth departed for a nine-week snowmobile and science trip across Greenland, during which they will traverse a major ice sheet to measure snowfall and melt rates. The collaborative effort is being funded by the National Science Foundation.
Over the next two months, the Greenland Traverse for Accumulation and Climate Studies (GreenTRACS) project will cover nearly 1,500 miles by snowmobile, drilling cores into the ice sheet and linking those cores with ground-penetrating radar profiles.
The team includes Dartmouth graduate students Karina Graeter and Gabe Lewis, mountaineer Forrest McCarthy, Boise State geophysics graduate student Tate Meehan and geosciences associate professor Hans-Peter Marshall. The collaborative research project also includes Dartmouth professor Erich Osterberg, who led the first year of the traverse and is the lead principal investigator of the project, and Boise State geosciences professor John Bradford.
The Dartmouth team will drill 16 cores by hand, each to a depth of 25 meters, and use geochemistry to date the cores. Seasonal changes in oxygen isotopes and other chemistry signatures provide markers for each summer season, and much like tree rings, provide a way to date the cores. The 25-meter cores represent snowfall over the past 30-50 years, allowing snowfall rates to be estimated at these sites. Ice layers in the cores provide a record of melt.
Because snowfall can vary significantly, it can be challenging to estimate snowfall rates between cores that are far apart. The Boise State team will use ground-penetrating radar systems, combined with the age of layers from the core sites, to map snowfall rates along the traverse route. Radars include multi-offset 500 Mhz and 1 GHz systems that allow profiling of density and depth, and high-resolution 6-18 GHz microwave systems for tracking near surface layers.
You can follow the group’s journey on a blog maintained by the Dartmouth group: http://greentracs.blogspot.com/