Thesis (doctoral)--Helsinki University of Technology, 2004. / Includes bibliographical references (p. 136-142). Also available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 53-54).

Thesis (Ph. D.)--University of Washington, 2005. / On t.p. "h" is subscript. Vita. Includes bibliographical references (leaves 113-125).

Thèse (M.Ing.) -- Université du Québec à Chicoutimi, 2006. / Bibliogr.: f. 123-127. Document électronique également accessible en format PDF. CaQCU

Thesis (Ph.D.)--Memorial University of Newfoundland, 1997. / Restricted until May 1999. Bibliography: leaves 266-276.

Ice shelves play an important role in the mass balance of an ice sheet, by providing a link between the ocean and ice. Melting at the base of an ice shelf can play a vital role in its mass balance and stability. Topographic channel features have been found on the base of ice shelves, and have been found to alter melting, however the mechanism behind this alteration is unknown. Petermann Glacier is a major outlet glacier in North West Greenland, draining approximately 6% of Greenland Ice Sheet. It terminates in a long, thin ice shelf, constrained within a high-walled fjord. The ice shelf has pronounced longitudinal channel features on its base, which limited observations suggest direct ocean currents in a mixed layer of ocean and melt waters, focusing melt in these regions. Petermann Glacier underwent two large calving events in 2010 and 2012, and the impact of these events, or possible further calving events, on basal melting is unknown. Using the MITgcm to model the ocean cavity beneath an idealised ice shelf, this thesis discusses the impact of basal channels on interactions at the ice base and circulation within the cavity. This is supplemented with a modelling investigation into the interactions beneath Petermann Glacier, and the impact of recent calving events. The inclusion of channels was found to have a stabilising effect on the ice shelf by decreasing the mean basal melt rate, caused by the refocusing, and decrease in intensity of, the meltwater layer flow beneath the ice shelf. This stabilisation and resulting 'survivor bias' explains why channels are commonly found on the base of warm water ice shelves. The model of Petermann Glacier found similar melt patterns to observational studies, however with a lesser magnitude. The calving events of 2010 and 2012 removed areas of ice shelf with low melt rates, resulting in little impact on the overall volume of ice removed through ocean melting, though further calving would vastly reduce the volume of ice melted. One consequence of calving is the increase in melting-induced undercutting at the ice front, leading to the potential for enhanced secondary calving.

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2005. / Bibliogr.: f. [194]-198. Document électronique également accessible en format PDF. CaQCU

This thesis studies the scattering properties of different types of imperfections in large Arctic and Antarctic ice sheets. Such irregularities include cracks, pressure ridges and both open and refrozen leads. The scattering by a transition region between sea ice and a very thick ice shelf, for example as is found in the Ross Sea in Antarctica, is also treated. Methods of solution are based on applications of Green�s theorem to the appropriate situation, which leads to either a single integral equation or a pair of coupled integral equations to be solved at the boundary between the ice and the sea water. Those equations over a finite interval are solved using numerical quadrature, while those over semi-infinite ranges are solved using the Wiener-Hopf method. Results calculated using different techniques are able to be checked against each other, giving us great confidence in their accuracy. In particular, the scattering by three ice sheets of different thicknesses is confirmed analytically by mode-matching coupled with the residue calculus technique. The scattering by the single irregularities is investigated partly for its own sake, and partly with the aim of using it to treat the scattering when large numbers of features are included in a single ice sheet. The principal objective of doing this is to observe the change in the general amounts of reflection and transmission as the background ice thickness is changed. There is enough variation in our results for us to conclude that there is definite potential for using the change in an incident wave spectrum after passing through a given ice field to estimate the background ice thickness.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 149-159).

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