Listening to glaciers in Greenland

Inaudible sound, i.e., infrasound, from glaciers is generated by glacier run-off and during calving events. Such sounds can be continuously monitored with microbarometer arrays. Changes in the rate of events can be retrieved with a resolution of a few seconds. Applying array processing techniques enables the identification of individual glaciers over ranges of tens of kilometers. We concentrated on the remote region around Qaanaaq in northwestern Greenland and found coherent infrasound of at least five glaciers over a period of 16 years. Knowledge on the dynamical behavior of these remote glaciers, and other glaciers, is important for assessing hazards due to glacier melt and calving, mass balance of ice sheets and consequently sea level rise. Here we use a novel technique involving passive infrasound measurements to show that remote land and sea terminating glaciers behave differently in terms of their temporal behavior during the seasons and years. Strong fluctuations in infrasonic activity are found over time, with the highest activity rates in 2019. Increased activity over the years of the land- ans sea-terminated glaciers is retrieved. We anticipate that monitoring glacier infrasound can contribute to complementary knowledge of the behavior of remote glaciers, as the glacial dynamics can be passively observed on a fine temporal scale.