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Summary of Proposal OCE1503

TitleCalving rates and impact on sea level (CRIOS)
Investigator Luckman, Adrian - Swansea University, School of the Environment and Society
Team Member
Professor Benn, Doug - The University Center in Svalbard, Arctic Geology
Joughin, Ian - University of Washington, Earth and Space Sciences, Applied Physics Laboratory, Polar Science Center
SummaryOne of the greatest uncertainties surrounding development of the Arctic regions concerns the way that glaciers in Greenland and the Arctic islands will respond to continued climatic warming. Currently about half of Greenland’s ice losses are through the release of icebergs into the ocean (calving), rather than by surface melt.Any increase in calving rates will have an immediate impact on sea level, while changes in the volume and trajectory of floating icebergs could significantly affect shipping and ocean ecosystems.

Despite its environmental and economic impacts, calving is very poorly represented in Earth System models. It is currently impossible to accurately predict how iceberg production will respond to climate change at the regional or global scale. Because of this uncertainty, the IPCC did not attempt to estimate future calving losses in its 4th Assessment Report (AR4). AR5, due in 2013, will incorporate results of the present generation of calving models, although large uncertainties remain. The development of robust, practical methods of modeling calving losses remains one of the most important goals in glaciology today.

CRIOS (Calving Rates and Impact on Sea Level) is an international research project funded by Conoco-Phillips and led by Doug Benn from the University Center in Svalbard (UNIS) that aims to fill this major gap in our ability to reliably forecast the impacts of global and regional climate change. CRIOS runs from 2012 to 2016 and will deliver to the international climate science community new, robust and efficient iceberg calving modules that can be integrated into the earth system models used to forecast future environmental change. A major part of this project involves the use of remote sensing to calibrate and validate these calving models. TerraSAR-X data is ideal for this purpose because it has sufficient spatial resolution and revisit capability to allow the retrieval of glacier dynamics at scales appropriate to the calving process.This TerraSAR-X proposal aims to fulfill the ice dynamics part of the overall CRIOS project.

In this TerraSAR-X element we will use feature tracking to retrieve surface velocities of CRIOS study glaciers through their seasonal evolution as they respond to changing atmospheric and ice-front conditions. Glaciers of interest include Kronebreen in Svalbard and Breidamerkurjøkull in Iceland, but we also aim to study the development of calving at a surge-type glacier (to be decided) and a West-Greenland outlet glacier (e.g. Rink Isbrae) which represents glaciers calving into much deeper water than in Svalbard. To sufficiently sample the temporal evolution of dynamic behaviour and its calving response, we require long sequences of 11-day repeat Stripmap-Mode imagery for each glacier. We also aim to use Spotlight-Mode data for shorter sequences at higher spatial resolution. In all, we request ~200 images to cover 4 glaciers through a whole year with extra capacity for Spotlight acquisitions.

We will deliver to the CRIOS project an unprecedented analysis of glacier surface velocities throughout the evolution of a full year of environmental conditions. In conjunction with other datasets, these data will be further processed to extract factors relevant to calving including ice fluxes, strain rates, calving patterns and iceberg characteristics. The CRIOS project will use these data, with other remote sensing and field datasets to deliver new, robust and efficient iceberg calving modules that can be integrated into the earth system models used to forecast future environmental change.

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