Measuring Bubble Pressure in Glacier Ice

• Main Author: Clonch, Cameron E.
• Other Authors: Pettit, Erin, Amundson, Jason, Wengrove, Meagan, Nash, Jonathan, Oregon State University. Honors College
• Format: Thesis
• Language: English
• Published: Oregon State University
• Subjects: Greenland; glacier; Tidewater
• Online Access: https://ir.library.oregonstate.edu/concern/honors_college_theses/8910k2833

Recent observations of tidewater glaciers find that the currently accepted model for predicting ice melt vastly underestimates observed melt rates. The release of pressurized air bubbles into the ocean from pores in the ice is one process that can amplify glacier melt. To incorporate this process into models, we need to define the buoyancy and pressure forces; higher pressure differences between the bubbles and surrounding water may create more disruptive bubble release events and greater buoyant energy contributions. In this paper, we provide a theoretical assessment of the factors that influence bubble pressure and initial results of an experiment to measure the pressure of bubbles within glacier ice. To determine bubble pressure, we use a pressure chamber device and chilled glycerol solution, allowing an up-close study of bubble release events. We find that ice from the Pakitsoq ice margin in West Greenland sustains elevated pressures in the air bubbles of 0.4 - 3.1 bar even after the ice has been extracted from the glacier and allowed to relax at atmospheric pressure for several years. By describing glacier ice melt rates with bubble pressure as a contributing parameter, we can improve current models and predictions of sea level rise. Key Words: bubbles, tidewater glacier, ice melt, sea level rise