Abstract
AbstractA common precursor to ice shelf disintegration, most notably that of Larsen B Ice Shelf, is unusually intense or prolonged surface melt and the presence of surface standing water. However, there has been little research into detailed patterns of melt on ice shelves or the nature of summer melt ponds. We investigated surface melt on Larsen C Ice Shelf at high resolution using Envisat advanced synthetic aperture radar (ASAR) data and explored melt ponds in a range of satellite images. The improved spatial resolution of SAR over alternative approaches revealed anomalously long melt duration in western inlets. Meteorological modelling explained this pattern by föhn winds which were common in this region. Melt ponds are difficult to detect using optical imagery because cloud-free conditions are rare in this region and ponds quickly freeze over, but can be monitored using SAR in all weather conditions. Melt ponds up to tens of kilometres in length were common in Cabinet Inlet, where melt duration was most prolonged. The pattern of melt explains the previously observed distribution of ice shelf densification, which in parts had reached levels that preceded the collapse of Larsen B Ice Shelf, suggesting a potential role for föhn winds in promoting unstable conditions on ice shelves.
Highlights
Ice shelves fringe around half of the continent of Antarctica
The broad pattern of melt duration and absolute number of melt days showed no significant disparity between the two approaches giving confidence that the advanced synthetic aperture radar (ASAR) wide swath mode (WSM) data were suitable for assessing surface melt at a higher spatial resolution than previously possible
Between approaches was not explored more quantitatively because the primary interest was in the spatial pattern of surface melt, rather than the absolute correspondence between melt duration derived by satellite and that experienced at the surface
Summary
Ice shelves fringe around half of the continent of Antarctica. They present a crucial interface between ice sheet, ocean and atmosphere, and serve to regulate the rate at which grounded ice is lost to the ocean, making it essential to understand their ongoing evolution (Dupont & Alley 2005, Solomon et al 2007). Where surface melting is common or prolonged, meltwater may percolate into the firn leading to densification, eventually to the point where firn air content approaches zero and no further infiltration is possible (Holland et al 2011, Kuipers Munneke et al 2014) This process transfers heat to deeper layers as water refreezes in the much colder firn (Vaughan 2008), potentially affecting ice shelf dynamics and the fracture toughness because both are strongly dependent on ice temperature and its variation with depth
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.
