Predicting the Arctic sea ice, piece by piece

Published Oct. 25, 2017
Predicting the Arctic sea ice, piece by piece

A discrete element model shows explicit ice floes, cracks and lead formation in the Beaufort Sea north of Alaska.

HANOVER, N.H. (Oct. 23, 2107) - Viewed from an airplane or a ship’s deck, Arctic sea ice can appear as an endless expanse of white ice and snow, punctuated by thick ice ridges and, in summer, pools of blue meltwater. 

Underneath the surface, though, the ice cover consists of separate ice floes that move in response to winds, currents, waves and mechanical forces from contact with the neighboring ice floes.  Ice floes feel the friction, stress and immense pressure from their moving neighbors.  This pressure can exceed the strength of the ice, leading to cracks, open water or leads and uplift of floes into ridges.

Researchers with the U.S. Army Cold Regions Research and Engineering Laboratory have developed a discrete element method model of the sea ice cover that calculates the dynamic forces and velocities of ice floes in the prediction of the breakup, ridging and open lead formation of the Arctic sea ice pack.

The DEM model calculates ice motion and breakup at a spatial resolution of 200 meters, starting from initial high-resolution satellite imagery of the ice pack. The model supports navigation and accessibility in Arctic waters, both on-ice and under-ice operations, where the integrity of the ice pack is in constant evolution and must be monitored for safety and mission success. 

“The discrete method is a significant advance over previous models that treated the ice cover as a continuous material,” said Dr. Arnold Song, CRREL.  “We can now predict the potential of the ice cover cracking when winds and ice drift change, making it safer for people to operate in the hazardous environment of the Arctic.”

The DEM can also predict the forces of sea ice on structures, such as an icebreaking ship’s hull moving through the ice pack and offshore platforms that support infrastructure in the Arctic. 

Modeling the entire Arctic ice pack at high resolutions was achieved by adapting the DEM to high-performance computers at the U.S. Army’s Engineer Research and Development Center’s Information Technology Laboratory. 

This research supports the Nation’s needs for improved predictions in the Arctic in sustaining Arctic science and exploration, safe navigation and national security.