http://hdl.handle.net/1983/929 2013-05-17T15:47:09Z http://hdl.handle.net/1983/1640 The PEG-BOARD project: a case study for BRIDGE Tourte, GJL; Tonkin, EL; Valdes, PJ Hedlund, Turid; Tonta, Yasar With increasing public interest in the area of historical climate change and in models of climate change in general, comes a corresponding increase in the importance of maintaining open, accessible and usable research data repositories. In this paper, we introduce an e-Science data repository containing extensive research data from palæoclimatology. Initially designed to support internal collaboration and organise data, the sharing of research outputs became an increasingly significant role for the service over several years of practical use. We report on a data preservation and interoperability assessment currently under way. Finally, we discuss the ongoing significance of open research data and capacity for analysis in the area of climate research, with palæoclimatology as a case study. 2010-06-01T00:00:00Z http://hdl.handle.net/1983/1169 Is Vostok lake in steady state? Royston-Bishop, George; Tranter, M; Siegert, Martin J; Lee, V; Bates, PD Stable-isotope (δD and δ18O) data from the Vostok (East Antarctica) ice core are used to explore whether or not subglacial Vostok lake is in isotopic steady state. A simple box model shows that the lake is likely to be in steady state on time-scales of the order of 104-105 years (three to four residence times of the water in the lake), given our current knowledge of north-south and east-west gradients in the stable-isotopic composition of precipitation in the vicinity of Vostok station and Ridge B. However, the lake may not be in perfect steady state depending on the precise location of the melting area, which determines the source region of inflowing ice, and on the magnitude of the east-west gradient in isotopic compositions in the vicinity of Vostok station and Ridge B. 2004-06-01T00:00:00Z http://hdl.handle.net/1983/1168 Spatial stability of Ice Stream D and its tributaries, West Antarctica, revealed by radio-echo sounding and interferometry Siegert, Martin J; Payne, AJ; Joughin, Ian It has been shown recently that ice streams are fed by fast-flowing tributaries occupying well-defined subglacial troughs and with shared source areas. Here, ice-penetrating radio-echo sounding (RES) data are analyzed in conjunction with ice surface velocities derived from interferometric synthetic aperture radar (InSAR), to determine the englacial properties of tributaries feeding Ice Stream D, West Antarctica. All of Ice Stream D's tributaries are coincident with "buckled" internal ice-sheet layers, most probably deformed by the processes responsible for enhanced ice flow. Between the tributaries well-preserved internal layers occur. The data reveal that no lateral migration of the ice-stream tributaries has occurred recently. This is consistent with thermomechanical ice-flow modelling, which indicates that the flow of Ice Stream D is controlled by a subglacial trough and is unaffected by changes to the flow of neighbouring Ice Stream C. 2003-06-01T00:00:00Z http://hdl.handle.net/1983/1167 Grain textural analysis across a range of glacial facies Khatwa, A; Hart, JK; Payne, AJ A technique proposed by Hooke and Iverson (1995) to identify deformed subglacial sediments is reviewed and tested, based on two main objectives. First, an investigation of whether the fractal dimension can distinguish between non-deformed and deformed facies; for which we compare supraglacial and subglacial facies explicitly. Second, an evaluation of whether the fractal dimension can be used as a diagnostic criteria to discriminate between different styles and degrees of basal deformation. This is tested using a range of sediments from the deformation continuum suggested by Hart and Boulton (1991b). Sixteen subglacial samples were selected from Quaternary sites in England and three supraglacial samples from the modern Haut Glacier d'Arolla, Switzerland. The mean fractal dimension for the subglacial diamicton matrix facies was 2.92, similar to findings of 2.90 by Hooke and Iverson (1995)for their basal tills. The supraglacial facies displayed a mean fractal dimension of 2.83, which is unusually high for facies which are assumed to be undeformed. A Mann-Whitney U test showed that fractal dimensions of supraglacial and subglacial diamicton matrix facies were not significantly different. No significant difference was found between the fractal dimensions of the different tectonic facies within the subglacial group. It may be impossible to separate the subglacial and supraglacial facies because of complex debris paths within the glacier. Grain fracture or parent lithology may affect the particle-size distribution of subglacial facies. 1999-01-01T00:00:00Z