skip to primary navigation skip to content
 

 

Scott Polar Research Institute - Physical Sciences Seminar

Seminars on polar physical sciences are held at the Scott Polar Research Institute during the Michaelmas, Lent and Easter terms. The seminars typically take place on Wednesdays between 16.30 and 17.30 and are held in the main lecture room, which can be accessed via the polar museum. Doors are open to public and all are welcome.

View the archive of previous seminars.

# Wednesday 18th October 2017, 4.30pm - Mr Michael Cooper
What lies beneath: a radio-glaciological study of Greenland.
Venue: Scott Polar Research Institute, main lecture theatre

Despite several decades of satellite and airborne geophysical surveys over the Greenland Ice Sheet (GrIS) there is still much that we do not know about the properties of the bedrock that lie beneath the ice, and to what extent basal characteristics influence ice dynamics. Whilst surveys were initially conducted to better constrain future sea-level rise contribution from glaciological modelling, radio-echo sounding (RES) has the potential to reveal basal characteristics relevant to both contemporary and palaeo-ice dynamics, and information regarding geology, landscape alteration and genesis.

This talk will detail several examples of this ‘extra’ information to be gleaned from RES conducted as part of my PhD research, as well as some future avenues for investigation.

# Wednesday 15th November 2017, 4.30pm - Dr Suzanne Bevan
Remote sensing of melt and fracture on Larsen C ice shelf, Antarctica
Venue: Scott Polar Research Institute, main lecture theatre

Surface meltwater ponding has been implicated in the recent break-up of ice shelves along the Antarctic Peninsula. I will present some observations of ponds on Larsen C ice shelf and show how they coincide with troughs in the surface mapped using synthetic aperture radar (SAR) interferometry. For ponds to form, the ice shelf surface needs to have undergone sufficient melt/refreeze cycles to densify the ice to the point at which it is impermeable to continued melt. It is relatively straightforward to spot surface ponding in optical satellite imagery but detecting liquid water within an unsaturated snow pack requires observations in the microwave. I will show how QuikSCAT and, recently available, enhanced resolution ASCAT radar scatterometry data reveals patterns and trends in melt on the ice shelf from 1999-2017.
Finally, I will show how we used interferometry and the Sentinel 1 SAR data to monitor the progression of the rift which caused the recent calving of the 5,800 km2 ice berg from Larsen C.

# Wednesday 29th November 2017, 4.30pm - Dr Adam Booth
Geophysical observations on Larsen C Ice Shelf: characterising stability after Iceberg A68
Venue: Scott Polar Research Institute, main lecture theatre

The floating ice shelves that fringe much of the Antarctic continent have become prominent in predictive models of sea-level rise. Once considered to be ‘passive players’ within the glaciological system, they are now considered to be significant buffers to ice loss from terrestrial Antarctic glaciers. The removal of that buffer via shelf collapse exacerbates the transit of terrestrial ice to the oceans. Larsen C Ice Shelf, on the Antarctic Peninsula, has been of particular interest in recent years following observations of i) a loss of shallow firn in its upstream reaches, and ii) a sporadically-propagating rift parallel to its calving front. Both of these mechanisms are invoked in ice shelf collapse, although it is the latter that is currently foremost in the public eye.

On 12th July 2017, Larsen C calved one of the largest icebergs ever observed. Iceberg A68 represents 12% of the Larsen C area although, as colossal as its vital statistics are, the calving event has more significance as a portent of shelf instability. The collapse of Larsen B in 2002, for example, was preceded in 1995 by a similar calving event; and followed thereafter by an acceleration of its tributary glaciers. However, observational control of the immediate aftermath of iceberg calving is sparse, hence the models with which ice shelf (in)stability is predicted are unconstrained.

In this talk, I will review the physical constraints that we (Leeds, Swansea and Aberystwyth Universities) have accrued for characterising stability-critical points around Larsen C. This will include an introduction to a new NERC Urgency Grant that seeks to quantify the mechanical properties of the ice shelf in the short-term aftermath of the A68 calving event.

# Wednesday 31st January 2018, 4.30pm - Amber Leeson, University of Lancaster
Surface meltwater on the polar ice sheets under a changing climate
Venue: Scott Polar Research Institute, main lecture theatre

The Greenland and Antarctic ice sheets hold enough water to raise global sea level by nearly 80 metres were they to melt away completely. While total loss of either ice sheet is unlikely in our lifetime, under current rates of climate change we can expect an ice-sheet contribution to sea level of around 10 cm by 2100; sufficient to double the number of people experiencing flooding worldwide. In addition to contributing directly to global sea level rise, ice sheet melting can act as a feedback to further accelerate ice loss and can impact the way in which we interpret spaceborne measurements of ice sheet volume change. As such, it is important that 1) estimates and predictions of ice sheet melting are well constrained and 2) that we have a good understanding of the interactions between the melt water and the solid ice. Melt water / ice-sheet interactions are particularly interesting as on its way out to sea, melt water passes through the supra- en- and sub-glacial environments where it can impact firn density, the thermal regime of the ice sheet and the way in which the ice slides over its bed. Here we will present an overview of recent work in this area, including a discussion on the role of temporary meltwater storage and the implications of this for ice sheet stability.

# Wednesday 14th February 2018, 4.30pm - Conrad Koziol, University of Edinburgh
Modelling seasonal acceleration of land terminating sectors of the Greenland Ice Sheet margin
Venue: Scott Polar Research Institute, main lecture theatre

Surface runoff during the summer melt season drains to the ice-bed interface of the Greenland Ice Sheet, leading to seasonal acceleration of land terminating sections of the margin. Understanding the processes driving this phenomena are important for predicting the dynamic response of the ice sheet to increasing summer melt season intensity. Land-terminating sectors also provide a useful environment for testing models of subglacial hydrology, before applying such models to the more complex marine-terminating sectors. This talk will cover efforts to model seasonal acceleration of land-terminating sectors of the Greenland Ice Sheet margin using a multicomponent model, consisting of supraglacial hydrology, subglacial hydrology, and ice dynamic components.

# Wednesday 28th February 2018, 4.30pm - Emrys Phillips, British Geological Survey, Edinburgh
Concentrated, “pulsed” axial glacier flow: structural glaciological evidence from Kvíárjökull in SE Iceland
Venue: Scott Polar Research Institute, main lecture theatre

A detailed structural glaciological study carried out on Kvíárjökull in SE Iceland reveals that recent flow within this maritime glacier is concentrated within a narrow corridor located along its central axis. This active corridor is responsible for feeding ice from the accumulation zone on the south-eastern side of Öræfajökull to the lower reaches of the glacier and resulted in a c. 200 m advance during the winter of 2013-14 and the formation of a push-moraine. The corridor comprises a series of lobes linked by a laterally continuous zone of highly fractured ice characterised by prominent flow-parallel crevasses, separated by shear zones. The lobes form highly crevassed topographic highs on the glacier surface and occur immediately down-ice of marked constrictions caused by prominent bedrock outcrops located on the northern side of the glacier. Close to the frontal margin of Kvíárjökull, the southern side of the glacier is relatively smooth and pock-marked by a number of large moulins. The boundary between this slow moving ice and the active corridor is marked by a number of ice flow-parallel strike-slip faults and a prominent dextral shear zone which resulted in the clockwise rotation and dissection of an ice-cored esker exposed on the glacier surface. It is suggested that this concentrated style of glacier flow identified within Kvíárjökull has affinities with the individual flow units which operate within pulsing or surging glaciers.

# Thursday 8th March 2018, 4.15pm - Walter Immerzeel, University of Utrecht
This talk is part of the Department of Geography Seminar Series
Recent advances in understanding climate, glacier and river dynamics in high mountain Asia
Venue: Small Lecture Theatre, Department of Geography, Downing Site

The Himalayan water cycle is poorly understood because the extreme topography results in complex interactions between climate, water stored in snow and glaciers and the hydrological processes. An accurate understanding of this water cycle is imperative because hydrological extremes in the region regularly cause great damage, while high mountain Asia supplies water to over 25% of the global population. In recent years, significant advances have been made in field monitoring, modelling and remote sensing and in this talk, the latest progress will be presented focussing on three related fields. First, on high altitude climate dynamics and the interaction between the atmosphere and the extreme mountain topography. Second, on how climate controls key glacio-hydrological processes in high-altitude catchments with a particular focus on debris covered glaciers. Third, on glacio-hydrological modelling and approaches to climate change impact assessments. Finally, the talk will synthesize the outstanding scientific challenges that must be addressed to fully close the high mountain water cycle, thereby reducing the uncertainty in future projections of water availability and the occurrence of extreme events in high mountain Asia.