Terminus Changes of Tidewater Outlet Glaciers in Greenland: Environmental Controls and Links to Glacial Earthquakes
The contribution of continental ice sheets to sea level rise has doubled in the last decade and the rapid acceleration of Greenland's outlet glaciers has been one of the dominant factors in this contribution. The largest changes in speed have been observed at the tidewater margins of these glac...
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DigitalCommons@UMaine
2011
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| Online Access: | https://digitalcommons.library.umaine.edu/etd/1616 https://digitalcommons.library.umaine.edu/context/etd/article/2645/viewcontent/Terminus_Changes_of_Tidewater_Outlet_Glaciers_in_Greenland__Envir.pdf |
| Summary: | The contribution of continental ice sheets to sea level rise has doubled in the last decade and the rapid acceleration of Greenland's outlet glaciers has been one of the dominant factors in this contribution. The largest changes in speed have been observed at the tidewater margins of these glaciers, implying a link between terminus position and glacier dynamics. By understanding the environmental controls on terminus position, we will be better able to predict future ice dynamic changes and ice sheet contributions to sea level. Here we examine decade-long records of terminus position for five major marine-terminating glaciers (Daugaard Jensen, Kangerdlugssuaq and Helheim glaciers in East Greenland, and Jakobshavn and Rink glaciers in West Greenland) to quantify seasonal and interannual variability in terminus changes. The time series are constructed from ~daily resolution MODIS satellite images. In order to understand the role of environmental conditions in governing the observed variability, we compile companion datasets of air temperature, sea surface temperature, and wind stress magnitude for regions adjacent to each outlet glacier. Results show that Greenland outlet glaciers undergo a seasonal pattern of summertime retreat and wintertime advance. The onset of retreat is highly variable, beginning as early as the start of March (before the start of the melt season) and as late as early August. Helheim and Kangerdlugssuaq glaciers show a substantial increase in seasonal variability following the onset of large changes in ice dynamics. Jakobshavn Isbrae has a more complex seasonal pattern, although it too has undergone a large change in ice dynamics. Rink and Daugaard Jensen glaciers exhibit relatively little interannual variability, which is consistent with their stable ice dynamics. There is a weak latitudinal pattern in the timing of the onset of retreat, but there is no obvious relationship between the length or intensity of the melt season and the duration or magnitude of retreat. These results indicate a ... |
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