Quantifying bed roughness beneath contemporary and palaeo-ice streams

Regional-scale bed roughness beneath ice masses: measurement and analysis

We outline a method of assessing the roughness of the bed beneath ice-masses, applicable to data collected in a wide variety of (glaciated) environments. Roughness at scales 410m in particular is poorly constrained and understood in glaciated systems, and regional geophysical surveys collected over the past 30 years are ideally suited to addressing this issue. We demonstrate the technique using...

Ice-Bed Coupling Beneath and Beyond Ice Streams: Byrd Glacier, Antarctica

Plastic bed beneath Hofsjökull Ice Cap, central Iceland, and the sensitivity of ice flow to surface meltwater flux

The mechanical properties of glacier beds play a fundamental role in regulating the sensitivity of glaciers to environmental forcing across a wide range of timescales. Glaciers are commonly underlain by deformable till whose mechanical properties and influence on ice flow are not well understood but are critical for reliable projections of future glacier states. Using synoptic-scale observation...

Subglacial floods beneath ice sheets.

Subglacial floods (jökulhlaups) are well documented as occurring beneath present day glaciers and ice caps. In addition, it is known that massive floods have occurred from ice-dammed lakes proximal to the Laurentide ice sheet during the last ice age, and it has been suggested that at least one such flood below the waning ice sheet was responsible for a dramatic cooling event some 8000 years ago...

Conduit Pressure Beneath Glaciers and Ice Sheets

The resistance to sliding beneath soft-bedded glaciers de5 pends on the effective stress N , which is controlled by the subglacial hy6 drological system. While large-scale water transport is primarily through 7 conduits, the effective stress profile beneath most of the glacier base is 8 expected to be controlled by seepage flows through the permeable sed9 iments. Models of the response to force...