CAREER: Chasing icebergs: quantifying iceberg motion and melt in Greenland's glacial fjords

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

Mass is being lost from the Greenland Ice Sheet both in the form of liquid water and solid ice. The solid ice occurs in the form of icebergs. The influence of these icebergs on the stratification and circulation of water in fjords, as well as on the freshwater content of the adjacent ocean, is poorly understood. This project will improve understanding of the role of icebergs in fjords and the coastal ocean through intensive process studies on iceberg melt and movement. These studies will include both field observations and numerical modeling experiments. The project will contribute to the development of the nation's STEM workforce by providing support for the training of a graduate student and a post-doctoral associate. To enhance the communication of science to the general public, a course in Geo-communication will be modified to include new multi-media approaches. Additionally, the project will allow the PI to extend his prior collaborations with University of Oregon's STEM CORE program to work with a local middle school on STEM-focused curricula. To enhance outreach to the broader public, the principal investigator will collaborate with a science historian to transcribe archived data into modern format that will be freely distributed, co-deliver public talks, add content to an existing website, and participate in an annual event on Climate Change and Indigenous Peoples organized by his institution. The ongoing surge in ocean-glacier interactions studies around Greenland is motivated primarily to improve our understanding of the role ocean circulation plays in outlet glacier variability. Two potential mechanisms that lead to glacier acceleration and dynamic thinning are (1) increased submarine melting due to an enhanced ocean heat transport to the glacier termini, and (2) a weakening of the ice mélange that buttresses the glacier face. Fjords act as links between these two processes with the large-scale climate forcing on one hand (both oceanic and atmospheric) and the Greenland ice sheet variability on the other. However, one key process, iceberg melt, has been largely neglected in most fjord circulation studies due to a narrow focus on plume driven circulation, as well as the overall difficulty of obtaining in situ observations. This proposal aims to gather novel observations on iceberg melt and movement in Greenland?s fjords by tracking the horizontal and vertical motion of large, deep-keeled icebergs at high temporal resolution. Tracking individual icebergs, combined with ship- and drone-based surveys, will allow quantification not only of iceberg melt rates, but also of their movement through the fjord and eventual dispersal across the shelf and into the interior ocean. Fieldwork will be conducted in relatively well-studied systems in Greenland, with the potential for rapid generalization to other systems. Complemented by numerical ocean modeling, these process studies will enable assessment of how well current parameterizations capture the melt processes occurring in Greenland's waters. Ultimately, these results will provide a solid foundation for improving understanding of the spatial and temporal picture of iceberg motion and melt and how this can be incorporated into operational iceberg trajectory models, as well as global scale climate models.