Abstract
Calving of glacial ice into the ocean from the Greenland Ice Sheet is an important component of global sea level rise. The calving process itself is relatively poorly observed, understood, and modeled; as such, it represents a bottleneck in improving future global sea level estimates in climate models. We organized a pilot project to observe the calving process at Helheim Glacier in East Greenland in an effort to better understand it. During an intensive one-week survey, we deployed a suite of instrumentation including a terrestrial radar interferometer, GPS receivers, seismometers, tsunameters, and an automated weather station. This effort captured a calving process and measured various glaciological, oceanographic, and atmospheric parameters before, during, and after the event. One outcome of our observations is evidence that the calving process actually consists of a number of discrete events, spread out over time, in this instance over at least two days. This time span has implications for models of the process. Realistic projections of future global sea level will depend on accurate parametrization of calving, which will require more sustained observations.
Highlights
Over the past few years, major changes along the periphery of the Greenland Ice Sheet have been observed occurring much faster than previously thought possible (Joughin et al, 2004, 2008)
Calving of glacial ice into the ocean from the Greenland Ice Sheet is an important component of global sea level rise
The calving process itself is relatively poorly observed, understood, and modeled; as such, it represents a bottleneck in improving future global sea level estimates in climate models
Summary
Over the past few years, major changes along the periphery of the Greenland Ice Sheet have been observed occurring much faster than previously thought possible (Joughin et al, 2004, 2008). When Amundson et al (2010) deployed cameras, GPS, seismometers (on bedrock), audio recorders, and water pressure sensors near the calving front of Jakobshavn, another Greenland outlet glacier, they observed large increases in the velocity of the mélange at the onset of calving events. Our GPS data suggest that the upstream effects of calving are limited until a full-width failure occurs of both the northern and southern trunks, indicating that even a relatively small portion of the glacier, in this case the southernmost trunk (~1.5 km wide), can provide significant backstress This backstress might be redistributed to the remaining intact portion of the glacier following the larger, primary calving event. We established on-land sites on a rolling basis over the last several years (Figure 4d) with one
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
