Jake Slobe | February 15, 2017
Iowa State University’s Neal Iverson and a team of researchers are working on research that will predict how much glaciers will contribute to the rise of sea levels.
The research will focus on the extent to which glacier-flow to oceans is likely speed up over the next century as the climate warms.
Iverson, an Iowa State University professor of geological and atmospheric sciences who has studied glaciers in Iceland and Norway, and the rest of the research team will look to lab experiments and field work to build more realistic computer models of glacier flow.
Iverson said about the project:
“Glaciologists are trying to predict how fast glaciers will flow to the oceans. To do that, we need new lab and field data to include complexity in models that is usually neglected. These are complicated systems. Modeling them is hard. But we need to include how water in ice affects its flow resistance, and we need sliding laws that are based on the real topography of glacier beds and that include rock friction. Adding these things really matters.”
Two new grants will help Iverson and his team fund their research, both of which grants are from the National Science Foundation. The research will also receive funding from the United Kingdom’s Natural Environment Research Council to support the work of applied mathematicians at the University of Oxford in England.
Iverson is the lead investigator on both grant proposals. The other researchers are Lucas Zoet, an assistant professor at the University of Wisconsin-Madison and a former postdoctoral research associate at Iowa State; Ian Hewitt, an associate professor and university lecturer at Oxford’s Mathematical Institute; and Richard Katz, a professor of geodynamics at Oxford.
The first project will look at temperate ice, or ice at its melting point, and how this soft, watery ice resists deformation. That’s important because the resistance to deformation of temperate ice at the edges of ice streams – areas of rapid ice flow within the Antarctic ice sheet that can be hundreds of miles long and tens of miles wide – holds back the flowing ice.
The second project will support development of better “sliding laws” to help predict the sliding speeds of glaciers and ice sheets. Sliding laws are the mathematical relationships between the glacier sliding speed and the factors that control it, such as the stresses below the glacier, the water pressure there, the topography of the glacier bed and the concentration of debris in glacier ice.
Both projects will use the glacier sliding simulator Iverson has been using since 2009 to study glacier movement.
The new projects will add complexity to Iverson’s lab experiments. Debris, for example, will be added to the ice ring to study friction between it and the rock bed during sliding. In other experiments, temperate ice will be sheared between rotating plates to study how its resistance to flow depends on its water content.