Using Acoustic Travel Time to Monitor the Heat Variability of Glacial Fjords

Abstract Monitoring the heat content variability of glacial fjords is crucial to understanding effects oceanic forcing on marine-terminating glaciers. A Pressure-sensor equipped Inverted Echo Sounder (PIES) was deployed mid-fjord in Sermilik Fjord southeast Greenland from August 2011 September 2012 alongside a moored array instruments recording temperature, conductivity and velocity. Historical hydrography used quantify relationship between acoustic travel time vertically-averaged content, new method developed for filtering return echoes an ice-influenced environment. We show that PIES measurements, combined with knowledge fjord’s two-layer density structure, can be reconstruct thickness temperature inflowing water. Additionally, we find fjord-shelf exchange events are identifiable record implying monitor fjord circulation. Finally, data records derive upper layer where at great risk being damaged by transiting icebergs.