EAS Seminar: Joel Harper (Montana)

Description

Meltwater’s Transformation of Greenland's Snow Layer in a Warming Climate: How Well Do Models Capture Observed Processes?

Melting across the Greenland Ice Sheet is accelerating as the Arctic warms at a rate significantly higher than the global average. A thick layer of densely compacted snow transitioning into ice (called firn) covers about 90% of the ice sheet. This layer initially absorbs much of the meltwater. However, as meltwater infiltrates and fills the firn’s pore space, its capacity to absorb additional water diminishes. An increasing proportion of the meltwater is then directed into runoff, contributing to sea level rise. Models sharply disagree on how the firn layer will respond to warming over the next century, ranging from modest changes to a severe loss of the firn layer, where nearly all meltwater would be routed into runoff. Through intensive field instrumentation and modeling, I identify several key processes of meltwater infiltration that current climate models poorly represent. Better representation of these processes is essential to determining the long-term fate of the ice sheet.

Bio:
Joel Harper is a professor at the University of Montana specializing in the cryosphere and climate. His research focuses on heat and mass transport in mountain snowpacks, small glaciers, and ice sheets, covering topics such as snow hydrology, ice deformation, and subglacial hydrology. By combining field instrumentation and modeling, he aims to enhance process-level understanding of Earth’s rapidly changing cryosphere. Prof. Harper has led numerous field research projects in Alaska, Montana, and Nepal, and has conducted over 20 field campaigns in remote locations on the Greenland Ice Sheet.