Wave Erosion at Ice Cliffs

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The decay of ice shelves, glaciers, and icebergs greatly influences the polar environment, with far-reaching implications for the global climate and sea levels. A key driver of ice loss in the polar regions is the wave-induced erosion of icebergs, glaciers, and ice-shelf fronts. While rapid progress has been made in recent years in understanding a number of ice decay processes, wave erosion at the waterline of ice cliffs has not been studied in detail. This project will conduct an in-depth investigation of wave erosion in a laboratory setting, with the goal to provide new insight on how ice cliffs erode and improve the representation of these processes in large-scale ocean and climate simulations. The primary focus is on icebergs since wave erosion is most impactful in the open ocean environment. However, many of the findings will apply directly to glacier and ice-shelf fronts. In addition to its scientific significance, the project will train two graduate students at the forefront of climate science. A further aim is to construct a basic wave flume for educational purposes and involve K-12 teachers in the study through summer research experiences. How ice cliffs decay is one of the most ardently researched questions in the cryosphere. A key driver of ice loss that has garnered relatively little attention in this context is wave-induced erosion. Wave action at the sides of icebergs and at the fronts of water-terminating glaciers and ice shelves can cause ice loss in several ways: (i) Waves mix meltwater and ambient water, efficiently transport heat toward the ice, and accelerate melt at the waterline. (ii) The resultant incisions at the waterline can lead to failure of the overhanging ice cliff. (iii) The remaining submerged ice is buoyant, and the induced stresses can trigger full-depth calving events. This project aims to conduct the first detailed investigation of these processes in a laboratory setting, which will be used to guide new theoretical considerations and the development of a revised iceberg erosion parameterization to be implemented in comprehensive ocean models. The primary objectives of this work are two-fold: (1) To gain insight into the fundamental physics of wave erosion and derive theoretical relationships between melt rates and environmental conditions. (2) To develop a decay parameterization that accounts for the processes (i)-(iii) above with the aim to reduce the uncertainty associated with ice loss in model projections. This constitutes an important next step toward the larger goal of more accurate climate projections and improved estimates of future sea level rise. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.