INVESTIGATING THE EFFECTS OF BASAL CHANNELS ON ICE SHEET MARGIN MELTING AT PETERMANN GLACIER, GREENLAND

Greenland is home to the second largest ice sheet on Earth, encompassing approximately 75% of the land, and 10% of the world’s total ice mass. Ice shelves, a prime place for ice loss in Greenland, are platforms of floating ice formed where a glacier, or in this case an ice sheet, flows from the surface it is on to meet the water on a coastline. Basal channels, defined as conduits carved into the bottom of ice shelves that direct water flow out from under the shelf, can form on ice shelves from where water circulation is causing uneven melting under the ice. This research will analyze the changes that basal channels under ice shelves in Greenland have gone through over time and how this affects the overall weakening, thinning, and melting that the glaciers are prone to as a result. The purpose of this study is to investigate the ocean-ice interactions within the Greenland ice sheet, specifically at Petermann Glacier whose ice shelf is dwindling, their effect on the global ice mass balance and the earth’s sea level rise.

There are three methodologies that will be used to evaluate how the ice at Petermann Glacier is being affected. The first are strain rates, used to calculate the stress and deformation of flowing ice and how it changes over the course of time. This is important at the sheer margins of the glacier where back stress is occurring. The second are digital elevation models. I will be looking at three-dimensional representations of Greenland’s terrain over time to show how the deformation of ice in Greenland has progressively changed. The third is altimetry, which at its simplest is a measurement of height. For my purposes I want to utilize measurements taken from NASA’s Operation Icebridge to understand the changes in elevation along Petermann Glacier as a result of accelerated melting.

My proposal is to evaluate the formation of basal channels underneath Petermann Glacier in Greenland over time, and establish a correlation between channel developments in relation to the stress at the margins of the ice shelf, the increase on strain rates, and the resulting effect on the release of back stress on the ice. I believe that strain rates will rise as more channels are formed from warm ocean water melting the ice near the grounding line and margins, and that this will increase melting and add to the shift in the global ice mass balance.