The motivation for our research is the need for better prediction capabilities of global sea level changes. The aim of our project is to extend the current knowledge of processes that are changing the Greenland Ice Sheet, its properties and its dynamics. This particularly requires a much better understanding of the linkages between the ocean, the atmosphere and ice sheet, as well as the peripheral glaciers in Greenland.
The focus of GROCE is a coordinated study of the glaciers Niogshalvfjerdsbræ (also referred to as 79°N Glacier) and Zachariæ Isstrøm. Both glaciers are located in the difficult to access and so far barely studied northeast of Greenland (see figure). As both glaciers recently started to retreat and there is growing evidence that their retreat will continue in the future, an interdisciplinary case study of this critical location is overdue to teach the ongoing changes.
1. Processes and mechanisms that contribute to basal melting at the interface between warm ocean water and the outlet glaciers:
- Which processes control the circulation of warm ocean waters at the the 79°N Glacier and Zachariæ Isstrøm?
- How large are the basal melt rates at the base of the glacier tongue and at the calving front - and what sets their magnitude?
- What drives the exchange of melt water and the surrounding ocean waters?
2. Effects of atmospheric conditions, seawater properties and topography on the dynamics of glaciers:
- Which atmospheric conditions cause surface melting and the formation of supraglacial lakes?
How much supra glacial meltwater is created and how is it directed to the glacier bed?
- What is the ratio of the fresh water input from the surface melt compared to the basal melt?
- How do the influx of warm ocean water and the supraglacial melt water influence (i) the basal melting rates, (ii) the grounding line*, and (iii) the melting at the calving front? *The grounding line marks the transition of the glacier from the inland ice to the glacier tongue.
- What changes do we expect in the near future in the relevant processes that drive these developments?
3. Teleconnections and feedbacks between Greenland's melting glaciers and the ocean circulation
- How does freshwater input from Greenland glaciers affect regional hydrography and ocean circulation?
- Can trends in drainage from glaciers and ice streams explain the observed changes in salinity distribution in the ocean?
- How does a changed ocean circulation and water mass distribution affect the heat transport from the ocean to the glaciers?
- How does the glacial-isostatic adaptation affect the complex earth-ice-ocean system?