The Swiss research prize will be awarded to Amy Macfarlane for her PhD investigating snow microstructure on sea ice. One of her findings showed that snow on sea ice does not only fall from the sky above but also forms from the sea below.
When the British PhD-student Amy Macfarlane embarked on ”the largest polar expedition in history” with the German research vessel Polarstern in 2020 she did not expect the scientific discovery she was about to make.
As the Polarstern was locked in the sea ice of the Arctic Ocean, she joined the vessel to conduct field work for her PhD thesis. Her topic was the microstructure of snow on sea ice, and along with her she brought research methods developed for Alpine research in Switzerland. Methods that had never been used on sea ice.
The data she and a team from the Snow and Avalance Research Institute (SLF) collected would consist of a full year of high-resolution snow measurements. This data would be used in her research to better understand heat transfer within the snow and the reflection of light from its surface.
But when she returned to the SLF in Davos, Switzerland, she noticed something unusual in the dataset. There was a reoccurring trend in all the snow samples collected in winter. This, she had not expected.
“It was a really interesting discovery,” Amy Macfarlane told Polar Journal AG.
“When I looked at the data there was a continuous trend. Snow in the Arctic is usually heterogeneous: you get decomposition and erosion as there is a lot of wind. The snowpack is never the same and it is always really bumpy.”
“So to have a signal that was so clear and so consistent throughout the winter was a big flag that something was happening that we didn’t expect,” Amy Macfarlane said.
Snow from below
What she had discovered was a surprise indeed. Contrary to what most people would expect, not all of the snow on the sea ice had come from the atmosphere. The consistent signal in the data indicated that some of the snow had come from the sea ice turning into snow.
In one chapter from her PhD, which was published in 2023, Amy Macfarlane estimated that approximately 28 percent of the snow was sourced from the underlying sea ice and not from the atmosphere.
“The key takeaway from that paper was that snow from sea ice isn’t being sourced from the atmosphere but is actually being sourced from the underlying sea ice,” she said.
On land, some studies had already indicated that water in the soil below was contributing mass to the snow. But no one knew the extent to which the same process was taking place on ice where much more (frozen) water is available below.
“We just hadn’t put two and two together to realize that the sea ice is a huge source of vapor. Before, we assumed that the snowcover was only coming from precipitation, so this is changing our view of the origin of snow on sea ice,” Amy Macfarlane said.
Contributing to climate models
At the moment sea ice is of much interest to Polar researchers. Every year, it forms and then melts, affecting huge areas of the ocean surface in both Polar regions.
A snowy, white surface reflects back 50-90 percent of the sunlight that hits it, while a blue ocean surface reflects back 2-5 percent. This is known as the albedo effect and has big implications for how climate change will impact Earth in the future.
In addition to the optical effects, snow on sea ice also works as an insulator for the sea ice below. So, understanding how the snow structure develops and change throughout the winter is essential for the world’s climate models.
Therefore, Amy Macfarlane’s work to understand the microstructure of snow on sea ice are important to say the least. Currently, predictions are that the Arctic will be ice free in summer within a decade.
“This is being predicted with very complex models, and to make good long-term predictions, we need to understand the most important processes to include in these models. This is what this work will hopefully contribute to,” Amy Macfarlane said.
The environmental impact of research expeditions
Since finishing her PhD, Amy Macfarlane has moved on to a postdoc position at The Arctic University of Norway in Tromsø and Northumbria University in the UK. But the importance of the discovery she made with her PhD is now being recognized back in Switzerland where she conducted her PhD.
In a ceremony held on December 3rd 2024, she will receive the Prix de Quervain 2024. The prize is awarded by the Swiss Polar Institute to early-career scientists for their outstanding MA, PhD or Postdoc works.
For Amy Macfarlane the recognition came as a welcome surprise.
“Going from a PhD to a postdoc can be difficult. I have to be really independent with my work now and I have to believe that what I am doing is making a difference. So, to receive this award is really amazing,” she said.
The prize comes with a check of 5000 Swiss francs, and Amy Macfarlane has already considered how she will spend this money. She wants to help mitigate the environmental impact of conducting Polar research.
“I am thinking about ways that we can standardize and advocate for environmental impact assessments of scientific expeditions in the Arctic. Impact assessments are a common practice in industry but in the scientific community, especially in the Arctic, they are often missing.”
“This is something that I’m already working on with a group of early career researchers, but with this prize, I hope to get some qualifications that will help the process,” Amy Macfarlane said.
Ole Ellekrog. Polar Journal AG
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