| Summary: | This project will take a multi-disciplinary approach to understanding the response of Petermann Glacier in northern Greenland to climate change in the past. Petermann Glacier drains a significant fraction of the northern Greenland ice sheet and terminates in a large floating ice shelf that is sensitive to ice-ocean interactions. Ice retreat over the last decade opens access to the fjord and presents an opportunity to understand sedimentation processes under the area previously covered by ice shelf and to calibrate reconstructions of past ice shelf variations. Using a variety of technologies and approaches on land, ice, and at sea, the investigators will map the bottom of the fjord in front of and under the ice shelf; reconstruct ocean conditions and their role in ice shelf variations through time; reconstruct the past extent of the glacier on land and the floating ice shelf; and reconstruct local relative sea level. Together these efforts will create a comprehensive picture of the climate conditions and response of the Petermann Glacier to these conditions over the last 10,000 years. Of key interest will be the timing, extent, rates of change, and variability (on land and in the sea) during the early Holocene when local relative sea level was over 100 meters higher than today (due to lagging isostatic rebound of the crust in response to deglaciation), but the inland ice sheet was still large relative to today. The investigators will address dynamic responses to multiple interacting variables over a range of response times (from tens to thousands of years) relevant to potential future impacts. Specific research questions include: 1) How sensitive is Petermann ice shelf extent to documented climate changes within the Holocene? 2) Is shelf response independent of, or linked to, variations in the grounded Petermann Glacier, ocean thermal conditions, or relative sea level (i.e., sill depth)? 3) What are the rates of change and variability of these systems in response to early Holocene warming, Neoglacial cooling, and recent warming? The project will support several young investigators and will provide them with both ship and land-based training experiences. The project includes significant international collaborations, with substantial in-kind contributions from non-U.S. sources that add value to the project. Planned outreach includes teacher participation in the field program and meaningful classroom involvement at several levels. Data were continuously sampled, digitized, and stored on a hard drive in Simrad EK80.raw datagrams (Approximately 1.2 Terabytes). Description of these datagrams can be found at: https://www.simrad.com/www/01/NOKBG0240.nsf/AllWeb/543880A07527F5D3C1257E52002246B6?OpenDocument Open source code and supported readers for these data can be found at: https://github.com/RobBlackwell/SimradRaw.jl to read in Julia and: https://bitbucket.org/echoanalysis/esp3/overview to use the ESP3 software package in MATLAB or to download the compiled version for non-MATLAB users on a Windows 64bits platform. At the time of publishing, the current version of the compiled release is v0.9.5, which can be downloaded as the attached file, “esp3_install_ver_0.9.5.msi”. Be aware that this software is under development so there may be more recent versions available.
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