Enhanced calving rates related to meltwater plume occurrence at Eqip Sermia, Greenland

Abstract

<p>Glacier calving plays a key role in the recently observed dynamic mass<br>loss of the Greenland ice sheet. Calving waves, generated by the<br>sudden detachment of ice from the glacier terminus, can reach tens of<br>meters of height and have devastating effects upon impact on<br>surrounding shores. In this study, we describe a new method for the<br>detection of source location and timing of calving waves, and the<br>analysis of their magnitude and spreading properties using a<br>terrestrial radar interferometer (TRI). This method was applied to<br>11,500 minute-interval TRI acquisitions from Eqip Sermia, Greenland.<br>More than 2,000 calving waves were detected within seven<br>days. Quantitative assessment with a Wave Power Index (WPI) showed<br>spatially distinctive patterns: the sector of the calving front ending<br>in deep water shows a higher wave activity (+49%) with higher<br>cumulative WPI (+34%) than the shallow sector. In combination with<br>a detection of meltwater plume locations, we highlighted a 2.3 times<br>higher occurrence of visible meltwater plumes in the deep sector than the<br>shallow one. We found both the cumulated WPI and the number of waves<br>to increase by more than 80% in the presence of a meltwater plume<br>in the deep sector while only by 30% in the shallow sector.  We<br>therefore explain the higher calving activity in the deep sector to be <br>strongly related to a combination of higher occurrence of meltwater plumes <br>and more efficient calving enhancement linked to better connections <br>to deep warm waters.</p>