Relationships between iceberg plumes and sea-ice conditions on northeast Devon Ice Cap, Nunavut, Canada

Abstract

AbstractThis study investigates the impact of sea-ice conditions on the production of iceberg plumes from two tidewater glaciers on Devon Ice Cap, Nunavut, Canada. These effects are quantified using a 12 year RADARSAT-1 satellite record from 1997–2008 that contains imagery from approximately every 1–2 weeks in the winter and every 1–4 days in the summer. Iceberg plumes identified in this record are verified against terrestrial time-lapse photography of Belcher Glacier from 2007–08. Results suggest a strong relationship between iceberg plumes and the retreat of sea ice from the glacier termini, with the plumes caused by both the release of previously calved icebergs (ice melange) and new glacier calving. Iceberg plumes are also sometimes observed at other times in the summer and in midwinter (occasionally on both glaciers simultaneously), with these events likely due to new glacier calving alone. Analysis of tides and air temperatures suggests that they provide a minor influence on the timing of iceberg plumes. Instead, it appears that changes in the presence of sea ice are dominant on seasonal timescales, although internal glacier dynamics likely play a significant role for winter plume events that occur when substantial thicknesses of landfast sea ice are present.