TORONTO, March 5, 2024 鈥� Will ice floating in the Arctic Ocean move faster or slower over the coming decades? The answer to this question will tell us whether marine transportation can be expected to get more or less hazardous. It might also have important implications for the rate of ice cover loss, which is hugely consequential for Northern Indigenous communities, ecosystems, and the global climate system.

While observational data suggest the trend has been towards faster sea ice speeds, climate models project that those speeds will slow down during the summer season. This contrast has led to some questions around the plausibility of the model projections.

In a , Lassonde School of Engineering Associate Professor and Postdoctoral Visitor Jamie Ward found that, while the mechanisms driving the ice slowdown remain plausible, questions remain regarding the timing of the slowdown.

鈥淯nderstanding how sea ice motion is going to change is clearly of interest, and yet we  didn鈥檛 really know if what the models were projecting was reasonable,鈥� says Tandon, who is also with the (CRESS) at 91亚色. 鈥淚t seems that we can expect sea ice to continue to speed up for some time, but there will be a point in the coming decades when the dynamics will shift.鈥�

Floating sea ice presents a particular hazard for marine transportation, says Tandon, pointing to a dramatic example from 2017 when sea ice trapped and sunk two fishing boats around Newfoundland. And the faster the ice, the more hazardous the conditions.

To understand why sea ice has been speeding up, Tandon says a spring can be a useful analogy. As temperatures warm and the ice thins, it can expand and contract more readily, just as a spring made of thinner metal can expand and contract more easily compared to a spring made of thicker metal.

鈥淎s the thinner sea ice expands and contracts more, it generates more momentum for the sea ice, just like one of those spring-loaded toy cars goes faster the farther back you pull it,鈥� explains Tandon.

However, this is not the only force acting on the ice, and when the ice gets thin enough, the internal stresses that produced 鈥渟pringiness鈥� start to fade and other forces start to dominate.

鈥淎s ice enters what they call a free drift state, the internal stress becomes negligible, and the external forces of wind and the ocean surface tilt start to dominate. The models suggest that changes in the wind and ocean surface tilt will drive a slowdown of the sea ice during the summer season.鈥�

Tandon says that while the models generally agree that this summertime slowdown will occur, they do not agree on when this slowdown will start. Some models suggest that the slowdown will start within the next decade while others suggest it will start toward the end of this century.

Faster ice drifts can create hazardous conditions for marine transport, so in that sense an ice slowdown could be seen as a positive, but Tandon says there are bigger considerations.

鈥淚t doesn't change the fact that sea ice cover is steadily declining, right? This is a concern because of the impact on ecosystems, the Indigenous populations that rely on being able to hunt certain animals, the animals鈥� ability to survive the changing habitat, and the overall effect on the global climate,鈥� says Tandon. 鈥淏ut, I would say it's marginally good news in that the models are suggesting that some of the worst aspects we were expecting about ice cover decline are not being projected.鈥�

About 91亚色

91亚色 is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91亚色鈥檚 fully bilingual Glendon Campus is home to Southern Ontario鈥檚 Centre of Excellence for French Language and Bilingual Postsecondary Education. 91亚色鈥檚 campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contacts: Emina Gamulin, 91亚色 Media Relations and External Communications, 437-217-6362, egamulin@yorku.ca

The post After decades of Arctic sea ice getting faster and more hazardous for transport, models suggest a dramatic reversal is coming, 91亚色 U study finds appeared first on News@91亚色.

Prof. Mike Daly, who led the instrument science team, available for interviews before and after historic NASA OSIRIS-REx mission drop this weekend

TORONTO, Sept. 21, 2023 - The much-anticipated arrival of the Bennu asteroid sample to Earth means researchers across Canada and the world will be able to study it to better learn about the origins of the solar system, thanks in part to work led by a 91亚色 professor at the . This Sunday morning, NASA鈥檚 OSIRIS-REx plans to make that brief, but key pit stop back to earth鈥檚 orbit to parachute a package to the Utah desert, and , 91亚色 Research Chair in Planetary Science with the couldn鈥檛 be more excited.

鈥淲e get most of our information from asteroids by meteorites that fall to earth and then we try to figure out where they came from,鈥� says Daly, who led theOSIRIS-REx Laser Altimeter (OLA) science team for the Canadian Space Agency (CSA). 鈥淲e have few meteorites that look similar to Bennu and a unique aspect is just how pristine this sample is. We don鈥檛 know what we will find, and now we have the opportunity to study material that just may never make it to Earth.鈥�

From helping get the spacecraft to the surface of Bennu, to choosing a sampling site, to collecting the data used to create the shape-model of Bennu, OLA contributed to the OSIRIS-REx mission in a number of key ways, says Daly, adding that Bennu is now the most highly surveyed body in the solar system. 

鈥淭his is the most accurate shape-model of an asteroid ever, the level of detail is unbelievable,鈥� he says. 鈥淎lmost three-billion measurements were taken to create a model representation of Bennu.鈥�

Daly, an expert in planetary exploration, simulation and space flight instrumentation, first started working on the concept back in 2008, while working for his previous employer. MDA carried out the building of the technology for the CSA when he moved to his role at 91亚色, but he continued to be the scientific lead on the project.

From among the more than half a million known asteroids in existence, Bennu was chosen for its proximity to Earth, size, mineralogy, and other key features, but the orbiting matter around it and rough exterior of the terrain still came as a surprise when OSIRIS-REx arrived at Bennu in 2018 and spent the next couple of years collecting information. Contacting the asteroid to take its sample and finding the surface to be relatively soft was another revelation.

The spacecraft was able to extract an estimated 250 grams of matter, which, once it arrives in Utah and is shipped to Houston to be opened, will be further studied, with 91亚色 looking specifically at the microthermal properties of Bennu. Due to the Canadian contribution to the mission, four per cent of the sample will be held in Canada for future research.

Asteroids are leftovers from the formation of the solar system, so the information contained in the Bennu sample will help scientists glean information about the early days of the solar system.

Other 91亚色 researchers involved in the project include Jeff Seabrook, who was the deputy instrument scientist and James Freemantle, who provided project management for Canadian researchers. Johns Hopkins University Applied Physics Lab were close partners in analyzing the data.

While the Bennu sample will stay on Earth, the spacecraft will continue back through space where it is planned to take measurements of another asteroid, Apophis. While Daly describes Bennu as a 鈥渨ell-behaved鈥� asteroid due to its relatively steady spin on one rotational axis, Apophis will prove more challenging to capture, due to its tumbling nature. Whatever they discover next, Daly is sure it will be yet another source of amazement.

鈥淚t really takes me back to my childhood, you know, watching astronauts land on the Moon and watching Viking land on Mars,鈥� he says. 鈥淚 have a strange job where I鈥檝e had the privilege of seeing a couple of missions that I had some significant responsibilities for and that part of the job I really love. Even from the initial images before we start working on it, it鈥檚 always cool and interesting and you think 鈥楴o one has seen it like this before鈥�.鈥� 

While Daly will be in the U.S. as part of the CSA team for the return mission, in the Earth Rangers Studio on Sunday, Sept. 24 from 10 a.m. to 2 p.m. The event will be open to the public with the cost of admission to the ROM.

Daly will be available for interviews ahead of the launch and in Houston until Sept. 29.

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