I am a glaciologist at Imperial College London.
I study the processes that control how ice sheets grow and shrink using modelling, satellite observations, and fieldwork.
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Our group works on the physics of glaciers, ice sheets, and their interactions with the ocean, atmosphere, and solid Earth. We combine mathematical modelling, field observations, and remote sensing. Here are some highlights.
During my PhD I studied the flow of water beneath glaciers and ice sheets through the development and analysis of mathematical models. I studied how ice-dammed lakes fill and drain beneath glaciers, showing how simple models can be used to predict approximately when lakes will drain, lakes can fill and drain chaotically, and lakes affect the flow of glaciers through their impact on subglacial water pressures.
George Lu, a PhD student working with me, recently published a paper examining how coupling between subglacial drainage and ice-stream flow affect how rapidly the ice stream retreats.
At the British Antarctic Survey I used radar to constrain present and past ice flow in the Ronne Ice Shelf region of West Antarctica. We employed a phase-sensitive radar system to measure the Raymond Effect — an ice-dynamical phenomenon at ice divides.
Subsequent work measured englacial ice flow and ice-sheet history across multiple field campaigns.
We have used data from this radar to measure englacial ice flow and help to determine the history of ice flow in Antarctica.
Elizabeth Case subsequently used similar data to measure the compaction of snow (and “firn”) into glacial ice.
In 2018 I co-led a paper presenting evidence that the West Antarctic Ice Sheet was smaller than it is today during the Holocene, in both the Weddell Sea and Ross Sea sectors. This work was done as part of a team of 10 scientists from 5 institutions across 3 countries. We hypothesized that readvance was caused by the delayed response of the lithosphere to unloading following the Last Glacial Maximum. The evidence for this came from ice-penetrating radar and radiocarbon found in subglacial sediments, and we examined the implications of and controls on the readvance using a continent-wide ice-sheet model. The image below comes from the paper. It shows maximum and minimum grounding line positions predicted by the model.
In a paper from 2016, we used phase-sensitive radar and GPS to infer vertical and horizontal ice flow fields throughout the thickness of Korff Ice Rise, West Antarctica. We used these englacial flow fields with radar observations of internal layers within the ice rise to show that the flow of his part of the ice sheet underwent a reorganization around 2-3 kyr ago. Continued research into the history of the West Antarctic Ice Sheet is bringing together geophysical and sedimentological data with ice-sheet modelling, to understand large-scale change during the last few thousand years.
Two Nature papers demonstrated that meltwater has been moving long distances onto and across many Antarctic ice shelves for decades. Julian Spergel’s, a PhD student who worked with me, publisehd a paper in the Journal of Glaciology quantifying surface meltwater drainage and ponding on Amery Ice Shelf from 1973 to 2019.
These observations of widespread supraglacial hydrology in Antarctica are interesting because as the continent warms, water could either move into areas where it can cause ice shelves to collapse, or it could evacuate water into the oceans as shown by one of our papers. The movie below, taken from a helicopter, shows a large waterfall at the front of the Nansen Ice Shelf.
This US–UK project investigates how surface meltwater influences ice-sheet dynamics on the Antarctic Peninsula. Fieldwork at Flask Glacier is combining ice-penetrating radar, GNSS, uncrewed aerial vehicles, and passive seismics to observe how meltwater is routed across and through Flask Glacier and other Antarctic outlet glaciers and how this affect ice flow. through and beneath the ice and affects flow.
Antarctic ice shelves slow ice flow and sea-level rise, but can collapse rapidly through fracturing driven by surface meltwater. My prior work showed that drainage networks move meltwater long distances towards the most fracture-vulnerable coastal regions of ice shelves, and that these networks grow larger in warmer summers. This project will ask how water moves across Antarctica’s surface, when and where ice shelves will be inundated this century, and how this will affect sea-level rise. We will combine satellite remote sensing, fieldwork in Antarctica and Alaska, and new mathematical models, incorporating results into ice-sheet models.
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During two austral summers I spent roughly two months traversing the West Antarctic Ice Sheet with a mountaineer, collecting GPS and ice-penetrating radar measurements of ice flow with the British Antarctic Survey. The traverses covered the Ronne Ice Shelf and surrounding ice rises.
During my first Antarctic field season, my field safety expert, Iain Rudkin, was also an amazing photographer. See some of Iain’s photography from Antarctica and elsewhere here. Even after 12+ hours on a snow mobile, Iain somehow found the energy to get out of the tent and capture whatever nice clouds (not scenery as we were in the flat-white) that were outside. When we got back I put his timelapse photography together with some videos of my own and arranged them over a composition by Steve Massey, written while at the British research base, Rothera:
Video and time-lapse from a skidoo traverse of the Ronne Ice Shelf conducted by the British Antarctic Survey during the 2013/14 Austral Summer. Time-lapse by Iain Rudkin. Music is “Jenny Island” — an unfinished composition by Steve Massey (freezabox.com). Video footage and video editing by Jonny Kingslake.
In April and May 2017 I spent four weeks traversing the Greenland Ice Sheet as part of an NSF-funded project investigating the refreezing of meltwater in snow and firn. The project was led by Asa Rennermalm, Regine Hock, and Marco Tedesco. Conditions on the ice sheet were memorably windy.
Windy conditions on the Greenland Ice Sheet, 2017.
Funded by a Lenfest Junior Faculty Development Grant, Elizabeth Case and I spent two weeks on the Juneau Icefield in collaboration with the Juneau Icefield Research Program. We accessed Camp 18 by helicopter and flew a DJI drone to create 3D site models (reconstructed by Martin Pratt from the footage).
We measured vertical englacial strain rates (including firn compaction) using a phase-sensitive radar and extracted around 80 m of ice core from six locations near the ice divide. The drone also captured ogive sets produced by ice falls near the camp.
I am committed to communicating glaciology and polar science to broad audiences. Regular events include:
During 2020, when in-person outreach was unavailable, I gave a series of “EI Live” online assessible lectures about my research:
Exhibits at the annual Lamont Open House have included a large-scale glacier goo demonstration, an Augmented Reality headset for manipulating a digital model of the Himalayas, a Google Earth tour with a 3D mouse, and a glacier-goo feature-tracking experiment to illustrate ice velocity measurements.
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