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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 12th October 2016, 4.30pm - Nial Peters
A journey into Erebus volcano, Antarctica
Venue: Scott Polar Research Institute, Seminar Room

Erebus volcano is a 3794 m high stratovolcano located on Ross Island in Antarctica. It is the most southerly active volcano in the world, exhibiting persistent degassing and occasional Strombolian eruptions. Additionally, Erebus hosts one of the few active lava lakes in the world making it a prime site for scientific study. The Mount Erebus Volcano Observatory is a long running project to study and monitor the volcano. In this talk I will give an overview of how fieldwork is conducted at Erebus and introduce some of the research that has been undertaken by Mount Erebus Volcano Observatory in recent years.

# Wednesday 26th October 2016, 4.30pm - Antonio Abellan
Linking ice-cliff and rock-slope failures
Venue: Scott Polar Research Institute, Seminar Room

Shear failure of ice during glacier frontal calving events shares many characteristics of rock-slope failures (RSFs) in high mountain areas; Nevertheless, the investigation of gravity-driven instabilities that shape rock cliffs and glacier fronts have been dissociated research topics so far.

The dynamic processes shaping the termini of glacier fronts – and thus directly a major contribution to sea level rise – have attracted the attention of the scientific community. Although recent research has shed light on the dynamics of tidewater glaciers, a full understanding of the calving phenomena is still elusive. This epistemic uncertainty may be related not only to the highly non-linear dynamics of the calving phenomena, but also to the 2D nature and the limited spatial and temporal resolution of the techniques typically used for investigating the rapidly evolving glacier front.

Through my two year Marie-Curie H2020 project, I am progressively adapting my previous research interests (4D investigation of RSF using Terrestrial LiDAR and Structure-from-Motion photogrammetry) to the investigation of glacier front dynamics, aiming to gain understanding of the processes leading to discrete calving events, to adapt landslide modelling techniques for investigating glacier response to external forces and to explore the apparent randomness of calving events. Working in the reverse direction, this research project will allow me to analyse a plethora of recorded calving events in order to shed light on natural slope evolution.

# Tuesday 8th November 2016, 1.00pm - Twila Moon (University of Bristol)
NOTE!!! UNUSUAL DAY (TUE) AND TIME (1-2 pm)
Greenland Ice Sheet motion, ice-ocean interactions, and other ambitions to understand the cryosphere
Venue: Scott Polar Research Institute, Seminar Room

Ice sheet mass loss has wide-ranging impacts, from increasing global sea level to changing regional ocean characteristics via heightened freshwater flux to influencing local ecosystem function. The modern satellite era provides unprecedented opportunities to understand ice sheet behaviour and its associated effects. Dr. Moon will discuss on-going work to understand fast moving outlet glaciers that connect the interior of the Greenland Ice Sheet to the ocean and new research determining the near-glacier fingerprint of freshwater flux once ice is lost from the ice sheet. Her research explores seasonal to decadal timescales, taking advantage of remote sensing instruments to understand changes across the entire ice sheet on the level of detail of individual glaciers and fjord systems. Along with discussing connections between rapidly changing ice sheet areas and broader environmental system, she will highlight new datasets that continue to increase scientists’ skill at characterizing, understanding, and predicting ice sheet change in a warming world.

# Wednesday 23rd November 2016, 4.30pm - Daniel Goldberg (University of Edinburgh)
Ice shelf-ocean interactions: self-organisation and instability
Venue: Scott Polar Research Institute, main lecture theatre

The ice shelves bordering the Antarctic coastline play an important role in both the hydrography of the Southern Ocean and the mass balance and configuration of the Antarctic Ice Sheet. On the oceanographic side, ice shelves provide a surface boundary condition that is different than either open ocean or sea ice, with melting and freezing rates determined by small-scale turbulence and shelf-scale circulation, the latter in turn influenced by melting and freezing rates as well as ice shelf thickness. In some instances under-shelf processes significantly influence open-ocean hydrological and biogeochemical properties.

On the glaciological side, the ice shelves control the distribution of normal stresses at the grounding line, which in turn affects ice mass flux from the continent. Thus ice shelves provide a pathway for the heat content of the ocean to cause changes in continental ice sheets — which in turn feeds back on circulation by modifying the shape of the ice shelf cavity. In the case of rapidly-evolving ice shelves exposed to warm Circumpolar Deep Water, numerical modelling of such interaction presents a large challenge, since most ocean general circulation models (OGCMs) are not designed to allow for changing boundaries.

I will first present results from my own studies which examined such interactions using an old method of ice-ocean coupling — an “asynchronous” (or “dump-and-restart”) approach, and discuss the results of the study as well as strengths and weaknesses of the asynchronous approach and why it is not ideal as we move forward from process modelling to global predictions of coupled ice-ocean behaviour. I will then discuss the development of a new, synchronously-coupled ice sheet-ocean model, the difficulties and what is done to address them, and some preliminary experiments with this framework, yielding interesting results.

A common theme arising from the old work and new is the fact that, from the ice sheet stability perspective, ice shelf thinning due to melting is not solely important close the grounding line, as commonly thought, and may be vitally important to constrain and model in other regions of ice shelves commonly overlooked. Luckily, new observing platforms are being developed that may enable us to do just this.

# Wednesday 1st March 2017, 4.30pm - Dr. David Amblas, Scott Polar Research Institute, University of Cambridge
Submarine canyons in polar and temperate margins: shaping mechanisms and long-term evolution
Venue: Scott Polar Research Institute, main lecture theatre

Submarine canyons are deep incisions observed along most of the world’s continental margins. Their topographic relief is as dramatic as that of any canyon or river valley on land but is hidden beneath the surface of the ocean. Our knowledge of canyons has therefore come primarily from remote sensing and sampling, and has involved contributions from various oceanographic disciplines. Canyons represent a critical link between coastal and shelf waters and abyssal depths; water masses, sediment, nutrients, and even litter and pollutants are carried through them. Advances in technology continue to provide new insights into canyon environments by pushing the frontier of deep marine observations and measurements. In this talk we will describe the main geomorphic features of submarine canyons and what is known about their formation and the fundamental processes controlling their long-term form and dynamics. We will present a simple model for the long-profile curvature of submarine canyons, inspired in fluvial systems, that includes the combined effects of turbidity currents and background (i.e. hemipelagic) sedimentation, and compare the range of model profile shapes with those observed in present-day continental slopes, 3D seismic data and experimental models. Finally we will introduce a relatively poorly known geomorphic agent in submarine slopes: the cascading of dense shelf waters. This oceanographic phenomenon occurs seasonally and only in certain polar and temperate margins through cooling, evaporation, sea-ice freezing and/or deep sub-ice shelf melting. It involves the massive transfer of energy and matter from shallow to deep waters and can result in appreciable sediment erosion and downslope transport. We will discuss about the distribution and hydrodynamics of these flows, its far-reaching effects on the seafloor relief, and whether it should be included in the classic turbidity current and mass-gravity transport continuum of processes and deposits formulated more than 70 years ago.

# Wednesday 15th March 2017, 4.30pm - Dr. Jerome A. Neufeld, Department of Earth Sciences & DAMTP, University of Cambridge
Controls on the rapid drainage of supraglacial lakes
Venue: Scott Polar Research Institute, main lecture theatre

TBC