Croucher Image Awards winner reveals the hidden beauty of West Antarctica ice flows
Dr Felix Ng (Croucher Scholarship1995) won the Croucher Image Awards 2021 with an image that captures not only an important scientific discovery, but also the beauty of that knowledge.
“I wanted people to be intrigued,” Dr Ng says when asked what inspired him to use satellite-based radar to create an image of ice stream velocity data in West Antarctica.
The image spans more than 1,000 kilometers of ice. Blue and bronze colours signify converging and diverging flow respectively, while black indicates ice speed exceeding 50 metres per year, dramatically illustrating features that to the naked eye are lost in an endless expanse of white ice.
Ng’s computer mapping image has also unlocked the complex mechanics behind ice stream networks. It shows the role of nonlinear ice rheology in ice-stream formation and helps elucidate the mechanisms controlling the spatial dynamics of ice-stream networks, which is helpful in predicting ice sheet response to climate change.
“Previously we had very fragmented measurements of the flow of the Antarctic ice streams,” he said. “You had to go there with GPS, put in stakes and a year later go back.”
“I discovered a new thing that people have never seen before,” he explained. “Seeing all those hidden structures led to a new theoretical concept.”
“The velocity field was thought to be somewhat smooth away from the obvious ice stream margins and confluences. But what the image shows is that not the case at all, the ice is being captured in a rather irregular way. There is a lot of fine-scale structure within the funnelling of ice into ice streams.”
Ng, a Reader in Theoretical Glaciology in the Department of Geography, University of Sheffield, spent the summer of 2002-2003 in Antarctica, after a year as a Royal Society-Fulbright postdoc-toral fellow at the University of Washington, Seattle.
“I did field work just up from the area of this image, and I flew over these ice streams. That opened my eyes to Antarctic ice streams. My DPhil (completed at the University of Oxford in 1998 aided by a Croucher Scholarship) was more about water flow under ice, glacial outburst floods and hydrology,” Ng said.
The ice, two to three kilometres thick and resting on rock and sediment, appears solid and inert, but it is not. Ice is viscous, like a thick custard, and its movement has implications not only for Antarctica, but also for rising sea levels and the planet’s future.
The ice in the trunk and tributaries in the image moves at one or two metres a day because it is sliding at the base, lubricated by water-laden sediment.
“The ice streams are like the arteries, conveyor belts capturing the ice from the interior and conveying it to the margins of Antarctica, to the ocean, where it breaks off as icebergs, contributing to concerns about rising sea levels.
“We’re losing ice at the margins and one fear is that the losing of these ice shelves may in turn allow these ice streams to speed up.”
The origins and interconnecting patterns of the ice streams are not well understood. Ng wrote a paper for Nature Geoscience in September 2015, titled “Spatial complexity of ice flow across the Antarctic Ice Sheet”.
“Understanding how ice-stream tributaries operate and how networks of them evolve is essential for developing reliable models of the ice sheets response to climate change,” he wrote.
Dr Felix Ng is a Reader in Theoretical Glaciology in the Department of Geography, University of Sheffield. After graduating in Engineering Science at the University of Oxford in 1994, he moved to the Mathematical Institute there to study a doctoral degree and completed his DPhil thesis on mathematical glaciology in 1998. Ng then held a Junior Research Fellowship at St. John’s College, University of Oxford from 1998 to 2002. He spent 2001 visiting the University of Washington, Seattle, as Royal-Society/Fulbright postdoctoral fellow. From 2003 to 2005, Ng was the Leavitt Research Fellow in Geosciences at the Massachusetts Institute of Technology. He was appointed as Lecturer in Glaciology at The University of Sheffield in 2005, and promoted to Senior Lecturer in 2012, and Reader in January 2018. Dr Felix Ng received his Croucher Scholarship in 1995.
To view Dr Ng’s Croucher profile, please click here.