Ocean Mapping

The Ocean Mapping Team

Ocean mapping is crucial to understanding the factors that control the growth and decline of the Greenland Ice Sheet – a feature of critical importance in the global climate and sea level system. The ocean mapping team will focus their efforts on compiling bathymetric (seafloor) maps of the Petermann Fjord, much like the 3-D map shown below, which uses existing data. More data is needed to produce more detailed and extensive maps of the entire fjord system, including regions that have recently been exposed by massive calving events in 2010 and 2012.

Seafloor mapping allows us to look at how the floating ice-shelf has interacted with the seafloor in the past, as certain features in the fjord can provide a record of past advances and retreats of the grounded portion of the glacier. Of particular importance is the location of “sills” or “pinning points” that represent the location of the transition from grounded ice sheet to the floating ice shelf. The distribution of these “pinning points” will be tied into to the history of the glacier as determined from sediment cores and sub-bottom profiles to gain an understanding of ice sheet dynamics.

The seafloor mapping data will also be used to look at the distribution of sediments on the seafloor, allowing us to understand where material is being eroded and where it is being deposited. Newly developed water-mapping capabilities will also allow us to explore whether there are seeps of gas or fresh water anywhere in the fjord system. Finally,

The key instruments used by the ocean mapping team are multibeam echosounders mounted on the icebreaker ODEN and a smaller vessel (SKIDBLADNER) operated by Martin Jakobsson. The SKIDBLADNER will allow us to map in the shallower waters near the edges of the fjord that the ODEN cannot access. We will process these data in near-real time on the vessel creating 3-D images that will guide our operations and our interpretations.

 

3D view of the Petermann Glacier looking from the Nares Strait towards the glacier and it termination in the Petermann Fjord. Multibeam bathymetry collected by Healy 2003 and CCGS Amundsen.

 

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