Image courtesy of NASA Earth Observatory
DOE researchers are using a coupled ice-ocean model to study melt channels beneath Greenland’s Petermann Glacier, shown here in July 2012.
Melting of ice sheets from Greenland and Antarctica will lead to sea level change. Predicting this change and its impacts requires understanding and capturing in models the processes that influence melt and glacier flow rates.
A modeling study has revealed complex interactions in the ice-ocean system, along with conditions and variables that will require scrutiny and more detailed modeling in future studies.
Several Greenland and Antarctic ice shelves have deep inverted channels in the direction of ice flow and running along the underside of ice floating over the ocean. Department of Energy researchers have developed a coupled ice-ocean model to understand the formation and evolution of submarine melt channels beneath the floating ice shelf of Greenland’s Petermann Glacier. This model uses the Community Ice Sheet Model (CISM) to simulate the flow of grounded and floating (shelf) ice and an ocean layer (or “plume”) model to represent interaction with the underlying ocean. Melting, bedrock topography, and flow processes at the point where the glacier departs into the ocean stencil channels into the ice base as it passes by. These channels help to control and preserve the ice shelf against excessive submarine melting. Calculations revealed that warming of subsurface waters would increase submarine melting. Surprisingly, slight cooling of subsurface waters also could generate a reorganization of the submarine melt pattern and catastrophic thinning of the ice shelf. Increased discharge of (fresh) subglacial meltwater at the grounding line also increases overall submarine melting through greater entrainment of relatively warm ocean waters.
Carl V. Gladish
New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
This study was funded by the IMPACTS project sponsored by the DOE Office of Science Biological and Environmental Research program.
Gladish, C.V., Holland, D.M., Holland, P. R., and Price, S.F. “Ice-shelf basal channels in a coupled ice/ocean model.” J Glaciol. 58 (212), 1527–1544 (2012).
University, DOE Laboratory