My research

My research project titled ‘The nature and dynamics of ice stream beds: assessing their role in ice sheet stability’ aims to explore the basal conditions and geomorphology of Pine Island glacier through the analysis of geophysical data. This work has two main aspects outlined below.

Basal controls on ice stream flow

The movement of glacial ice is influenced by the terrain over which it flows. Characteristics of the bed’s geology, hydrology and topography determine the dynamics of ice flow. My research utilizes geophysical data to assess these characteristics in order to understand how they may influence the dynamics of Pine Island Glacier.

3-D Bed topography of Antarctica. Warm colours indicate bed elevations above present-day sea-level. Cool colours are bed elevations below present-day sea level. Data from Bedmap2 (Fretwell et al., 2013).

 

From this data I can produce 3-dimensional images of the topography of the ice stream bed and analyse temporal changes in basal conditions from repeat radar surveys. This information is important for improving the parameterization of ice stream beds in computer models used to predict the future behaviour of the West Antarctic Ice Sheet.

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Operating an ice penetrating radar on Pine Island Glacier (credit: D.Davies).

 

Ice Stream Geomorphology

The other branch of my research is investigating landforms created beneath fast flowing ice streams. Ice streams drain ice from the interior of the Greenland and Antarctic Ice Sheets and have in the past drained ice sheets located over North America and Europe during the last glacial period. In Antarctica they are responsible for 90% of the drainage of ice from the interior of the continent and therefore are important in controlling the mass balance (the balance of ice accumulation and ice loss) of the ice sheet.

Landforms developed under former ice streams (or palaeo-ice streams) have been identified based on their streamlined appearance and include features such as drumlins and mega-scale glacial lineations (MSGL)1,2. MSGL are highly elongated ridges (over 10s of km in length) and are thought to formed in sediments beneath flast fowing ice. There is little data from beneath modern ice streams to test theories for their formation. Similarly, drumlins have been studied for decades yet no theory of their formation is widely accepted.

Radar-derived 3D topography of the bed of Pine Island Glacer. Data: D.Davies.
Radar-derived 3D topography of the bed of Pine Island Glacer. Data: D.Davies.

My research will provide data to test these theories and allow direct comparisons between palaeo and contemporary ice stream beds. This will enable new insights into how landforms are related to ice dynamics. For this work I use radar data from Pine Island Glacier and sub-ocean bathymetric data collected offshore, downstream of the present day ice-front that reveal landforms created during retreat of the ice stream from a more advanced position during the last glacial period (see image below).

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Streamlined landforms on a palaeo-ice stream bed offshore of the modern Pine Island Glacier ice shelf. Ice flow is from right to left. (Data from Nitsche et al., 2013).

 

1. Clark, C.D. (1993). Mega-scale glacial lineations and cross-cutting ice-flow landforms. Earth Surface Processes & Landforms, 181-29.

2. Stokes, C.R. & Clark, C.D. (2002). Are long subglacial bedforms indicative of fast ice flow?  Boreas, 31: 239-249.