Ice casting: what is the role of waves?

Since the industrial revolution the ice pack has continued to melt, endangering dozens of animal populations. This disaster evolves from day to day, affected by various factors and mainly by man. But in this phenomenon, nature obviously plays an important role. So it’s to find out more about how the ice melt is going to change over the next few decades, an oceanologist from Canada decides to assemble a team of researchers to understand the effect of waves on the ice pack.

In addition, if you are interested in the current sea issues, I suggest you read the article “Mediterranean: A Step Forward towards Plastic-Free Biodiversity” *

Image taken during the expedition led by researcher Peter Sutherland

It is important to note that the first crystals appear in sea water at -2°C, to make up the pack ice. It is never more than a few metres thick because when the ice layer covers the sea, the process slows down. This is an astonishing fact, since in reality, seawater begins to freeze at a depth of about thirty metres and not from the surface as in freshwater lakes.

Only an intense and rapid cooling allows the salt to be ejected and form the frazil. As a result, ice crusts resembling pancakes collide and end up welding into continuous pack ice.

Twenty years ago, this pack ice measured more than three metres of thickness.Today, it is only 1.5 metres.

It also lost the equivalent of three times the surface area of France. That is why ice melt has become a major issue for our decade and why researchers are trying to put at their disposal all possible means to study this problem in order to solve it in the future.

Researcher Launches 5-Year Expedition to Discover the Impact of Waves on Melting Ice

A series of unprecedented measures will be implemented over the next five years. Submarine, ice canoe, aircraft and satellite will be deployed at the estuary of the St. Lawrence River and the Arctic Ocean, as part of the ERC WAAXT project led by Peter Sutherland, researcher at the Laboratory of Physical and Space Oceanography (LOPS – Ifremer/UBO/CNRS/IRD).

Waves that hit the ice pack can weaken the ice but can also thicken it. Moreover, by melting, the pack ice leaves room for the open sea and thus for an increasingly large wave field.

To better understand the effect of waves on the ice, Peter Sutherland wants to multiply the data: So far, many theoretical studies have been conducted on the subject. But very few campaigns took place on site, at sea, to validate the calculation tools.”

To fill this gap, the European Research Council (ERC) has awarded a young researcher grant of EUR 2 million over five years. Only five such grants were obtained by French researchers in 2018 in the field of earth sciences. The project is called WAAXT, Wave-modulated Arctic Air-sea Exchanges, and Turbulence.

The first measurement campaigns will take place in a natural laboratory developed since 2014 by the Institut des Sciences de la mer de Rimouski, of the Université de Québec. It is an instrumented bay close to the institute, an ideal setting for studying small-scale processes and testing new instruments in a controlled and accessible area in conditions similar to the Arctic. Then the advancements made in this lab, on the scientific and engineering side, will be applied to larger-scale experiments in the Arctic Ocean.

As part of the WAAXT project, innovative measures will be deployed at all ladders, from kilometres to centimetres. Three small, autonomous submarines equipped with sensors will criss-cross the ocean boundary, under the waves and under the ice, while air and satellite measurements will measure waves and ice. In addition, scientists will run on an ice canoe to measure the mechanical properties of the ice.

Who is Peter Sutherland?

Originally from Canada, Peter Sutherland finished his thesis on turbulence and waves in 2013 in the United States (Scripps Institution of Oceanography in San Diego). He then completed a post-doctoral degree at Sorbonne University on the interaction between waves and pack ice. He arrived at Ifremer as a physical oceanographer researcher in October 2015. To carry out his project, he will be able to surround himself with a team of two Ph.D. students and two post-docs.

To remember:

  • Twenty years ago the pack ice measured more than three meters of thickness.Today it is only 1.5 meters.
  • It also lost the equivalent of three times the surface area of France.
  • In order to better understand the effect of waves on ice, Peter Sutherland wants to multiply data in the Arctic.

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