Now showing items 1-7 of 7
Air Compression as a Mechanism for the Underdamped Slug Test Response in Fractured Glacier Ice
Contributor:Meierbachtoll, T. W.; Harper, J. T.; Humphrey, Neil; Shaha, J.; Bradford, J. H.
Artificial perturbations of borehole water levels, known as slug tests, are a useful means of characterizing the glacier hydrologic system. Slug tests were performed on Bench Glacier, Alaska, in 21 boreholes over three ...
Two Modes of Accelerated Glacier Sliding Related to Water
Contributor:Harper, J. T.; Humphrey, Neil; Pfeffer, W. T.; Lazar, B.
We present the first glacier-wide detailed measurement of basal effective pressure and related observations including bed separation to elucidate the role of water in sliding. The hard bedded glacier instrumented in our ...
Georadar-Derived Estimates of Firn Density in the Percolation Zone, Western Greenland Ice Sheet
Contributor:Brown, J.; Bradford, J.; Harper, J.; Humphrey, Neil; Pfeffer, W. T.; Mosley-Thompson, E.
Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland's percolation zone, where ...
High Altitude Himalayan Climate Inferred from Glacial Ice Flux
Contributor:Harper, J. T.; Humphrey, Neil
Glaciological processes are modeled to investigate precipitation patterns and the resulting mass flux of snow and ice across Himalayan topography. Our model tracks the accumulation and ablation of snow and ice and the ...
Topographic Control of Asynchronous Glacial Advances : A Case Study from Annapurna, Nepal
Contributor:Pratt-Sitaula, B.; Burbank, D. W.; Heimsath, A. M.; Humphrey, Neil; Oskin, M.; Putkonen, J.
Differences in the timing of glacial advances, which are commonly attributed to climatic changes, can be due to variations in valley topography. Cosmogenic Be-10 dates from 24 glacial moraine boulders in 5 valleys define ...
Thermal Tracking of Meltwater Retention in Greenland's Accumulation Area
Contributor:Humphrey, Neil; Harper, J. T.; Pfeffer, W. T.
Poorly understood processes controlling retention of meltwater in snow and firn have important implications for Greenland Ice Sheet's mass balance and flow dynamics. Here we present results from a 3 year (2007-2009) field ...
Depth-Varying Constitutive Properties Observed in an Isothermal Glacier
Contributor:Marshall, H. P.; Harper, J. T.; Pfeffer, W. T.; Humphrey, Neil
Detailed three-dimensional in-situ measurements of deformation at depth are used to examine the rheology of a 6 x 106 m3 block of temperate glacier ice. Assuming that the viscosity of this ice is primarily dependent on ...