Science Service System
You are here : Home : Proposals_Summary

Summary of Proposal LAN0701

TitleAssessing structural controls on ice shelf stability
Investigator Holt, Tom - Aberystwyth University, Centre for Glaciology
Team Member
Professor Glasser, Neil - Aberystwyth University, Centre for Glaciology
Dr. Quincey, Duncan - Aberystwyth University, Centre for Glaciology
Mr Holt, Tom - Aberystwyth University, Centre for Glaciology
SummaryThis project aims to establish the structural evolution of key ice shelves around the Antarctic Peninsula (AP) from the early 1970s to the present to test the hypothesis that ice shelf structure and dynamics are directly linked to processes governing ice shelf collapse. The last three decades have seen the retreat and collapse of several AP Ice Shelves; notably Wordie, Prince Gustav Channel, Larsen A, Wilkins and Larsen B. Ice shelf collapse has been attributed to a southward shift of a critical thermal boundary, coupled with both changes in atmospheric and oceanic regimes (Shepherd et al., 2003) and changes in glaciological structure (Glasser and Scambos, 2008). Although the retreat and collapse of ice shelves does not directly affect global sea level, their removal has seen increase in flow velocities and an extension of mass of tributary glaciers into a marine environment (Hulbe et al, 2008). It is these systems that contribute to sea level rise. A total melt of the West Antarctic Ice Sheet, potentially triggered by the removal of ice shelves, would result in a global sea level rise of 5m (Vaughan, 2005). Few studies to date have detailed the structural evolution of ice shelves prior to collapse, and fewer still evaluate the dynamic response of ice shelves over temporal scales that represent the atmospheric temperature increases observed over recent decades. Thus, this study focuses on the structural and dynamical changes of ice shelf systems and will evaluate the processes that control ice shelf collapse. Specifically, we aim to i) identify structural and dynamical changes of key AP ice shelves from the 1970s to present, ii) Quantify fluctuations in extent of these ice shelves, iii) identify changes in surface meltwater distribution, and iv) derive multi-annual surface velocities for AP ice shelves to highlight shifts in dynamical regime. To achieve this, we will delineate ice margin and grounding line positions over time to quantify changes in ice shelf morphology. Secondly, surface features such as longitudinal and transverse flow lines, meltwater features, surface debris, ice folds and associated features will be identified on sequential images to highlight structural changes, and potential mechanical controls on ice shelf morphology. A wide range of multi-temporal optical (Landsat, ASTER) and radar (ERS-1/2 SAR, Envisat ASAR and TerraSAR-X) images will be analysed to ensure comprehensive coverage. Finally, we aim to derive ice shelf velocity information for selected areas using well established interferometry (Rignot et alž 2004) and feature tracking (Luckman et al., 2003) techniques. Such information is sparse for Antarctic ice shelves, particularly over decadal and sub-decadal timescales. As a result, we will test the hypothesis that ice shelf structure and dynamics play a significant role in determining potential ice shelf collapse. The Principle Investigator has been awarded 3-years PhD funding from the Institute of Geography and Earth Science at Aberystwyth University in order to carry out this research. He has experience in cryospheric remote sensing; in particular glaciological mapping via optical data sets and interferometric processing of ERS-1/2 SAR data. His Co-Investigators have proven expertise in establishing the links between glacier structure and dynamics and their influence on large-scale changes in extent (Glasser et al, 2009), as well as extracting surface dynamics information in challenging environments using SAR-based approaches (Quincey et al, 2009). Aberystwyth University is computationally well-equipped with full licences for the software necessary to carry out such work (e.g. GAMMA, ENVI) as well as hardware capable of processing and storing large images datasets. In order to fulfil objections i) to iv) we require access to a total of 32 archived and planned TerraSAR-X data in Single Look Complex, Spatially Enhanced, Stripmap, Single Polarisation format (SSC_SE_SM_S).

Back to list of proposals

© DLR 2004-2016