Acoustical remote sensing of ice sheets and tidewater glaciers: recent progress and remaining challenges

The stability of major ice sheets in polar regions are linked to sea level rise and the input of fresh meltwater into sensitive regions of the thermohaline circulation system, two critical issues related to global change. Global melt of glaciers, ice caps, and ice sheets currently contributes almost 1 mm per year to total sea level rise. In addition, the freshening of surface waters affects global-scale heat transport by weakening Atlantic meridional overturning circulation. For these and other reasons, understanding the mass loss of glaciers is an important problem. Here we focus on studying the behavior of tidewater glaciers using the various sounds they make in the ocean as they flow, melt, and break apart. Melting glacier terminus, iceberg calving and freshwater discharge all create underwater signals with distinct temporal and spectral properties. We will discuss the potential for these sounds to be recorded, separated and calibrated to provide quantitative estimates of iceberg calving flux and the melt rates of glacier termini. Recent progress and remaining challenges will be highlighted. [Work supported by US Grants OPP-1748265 and ONR N00014-17-1-2633, Institute of Geophysics, Polish Academy of Sciences Grant 2a/IGF PAN/2017, and the Ministry of Science and Higher Education of Poland under ‘Mobility Plus’ program]