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Increasing surface runoff from the Greenland Ice Sheet due to a warming climate not only accelerates ice mass loss by altering surface mass balance, but may also lead to increased dynamic losses. This is because surface melt draining to the bed can reduce ice-bed coupling, leading to faster ice flow. Understanding the impact of surface melt on ice dynamics is important for constraining the contribution of the Greenland Ice Sheet to sea level rise. The aim of this thesis is to numerically model the influence of surface runoff on ice velocities. Three new models are presented: an updated supraglacial hydrology model incorporating moulin and crevasse drainage, along with lake drainage over the ice surface via channel incision; an ice sheet model implementing a numerically efficient formulation of ice flow; an adjoint code of the ice flow model based on automatic differentiation. Together with a subglacial hydrology model, these represent the key components of the ice sheet system. The supraglacial hydrology model is calibrated in the Paakitsoq region. Model output shows the partitioning of melt between different drainage pathways and the spatial distribution of surface drainage. Melt season intensity is found to be a relevant factor for both. A key challenge for simulations applying a coupled ice-flow/hydrology model is state and parameter initialization. This challenge is addressed by developing a new workflow for incorporating modelled subglacial water pressures into inversions of basal drag. A current subglacial hydrology model is run for a winter season, and the output is incorporated into the workflow to invert for basal drag at the start of summer in the Russell Glacier area. Comparison of the modelled subglacial system to observations suggests that model output is more in line with summer conditions than winter conditions. A multicomponent model integrating the main components of the ice sheet system is developed and applied to the Russell Glacier area. A coupled ice-flow/hydrology model is initialized using the proposed workflow, and driven using output from the supraglacial hydrology model. Three recent melt seasons are modelled. To a first order, predicted ice velocities match measured velocities at multiple GPS sites. This affirms the conceptual model that summer velocity patterns are driven by transitions between distributed and channelized subglacial hydrological systems.

This thesis attempts to understand the nature of the Greenlandic image "Tupilaq" in traditional Kalaadlit culture and in its modern context. The same term is applied today in Greenland to a variety of images carved as small figures for the tourist or art markets. This thesis examines the ways in which the images and the application of the term have changed. This study describes the traditional context of the TUPILAQ image and establishes a time frame for the inception of carvings labelled "Tupilaq". Data used to support this investigation were drawn from ethnographic records, historical accounts, and museum exhibit reports. It becomes clear that the Tupilaq figure exists as a distinct and new category of material culture which stands apart from its mythic image. An analysis of these carvings and interviews with their carvers show that the content of Tupilaq figures is not what their label implies. The analysis is carried a step further, examining the development of this carving production, the market for these carvings as cultural artifacts, and the concerns of their producers and consumers. This investigation demonstrates that the ways in which East Greenlanders modified and continue to modify this carving production relates directly to their necessity to establish their group's identity in a changing cultural environment. This thesis shows that the label -Tupilaq- is the symbolic link between traditional and contemporary society. In conclusion, interpretation of material culture is discussed as it applies to Tupilaq figures; we need to go beyond the label for a more adequate interpretation of the content and the occurrence of cultural images as material objects. / Arts, Faculty of / Anthropology, Department of / Graduate

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Approved for public release; distribution is unlimited / Presently ice extent forecast models such as the U.S. Navy Polar Ice Prediction System (PIPS) neglect or treat small-scale thermodynamic processes and entrainment unrealistically. Incorporating better algorithms that include more complete physics of the mixed layer dynamics will allow for improved prediction of ice thickness and distribution, open water boundaries, polynyas, and deep-water formation in the polar seas. A one-dimensional mixed layer turbulent kinetic energy (TKE) budget model based on Garwood's NPS mixed layer model for deep convection (Garwood, 1991) was written in MATLAB. The model consisted of a system of ten equations derived by vertically integrating the budgets for heat, momentum, salinity, and turbulent kinetic energy between the sea-ice-air interface and the base of the turbulent mixed layer. The NPS mixed layer model was tested using atmospheric forcing and ocean profiles collected at the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) site. Sensitivity studies using ocean profiles of the Greenland Sea were also conducted to address thermodynamics and ocean profiles that enhance thermohaline circulation. Findings and results as well as recommendations for further study are addressed to extend the relationships determined from small 1-D scales to the larger 3-D scales suitable for improvements to current ice models. / Lieutenant, United States Navy