PEARL’s High Arctic researchers keep an eye on the ozone layer

Midway up Ellesmere Island in Canada’s High Arctic, near the Eureka weather station, scientists are using a variety of instruments to study the atmosphere and gauge how well the ozone hole is healing.

At the Polar Environment Atmospheric Research Laboratory, or PEARL, the most critical part of this year’s work recently wrapped up.

From February 25 to March 13, a team of researchers were busy gathering a variety of atmospheric data, to help double-check measurements taken by two satellites of the Earth’s ozone.

One experiment, called ACE—for Atmospheric Chemistry Experiment—measures atmospheric chemistry.

The other, called OSIRIS—for Optical Spectrograph and InfraRed Imaging System—looks at how sunlight scatters in the atmosphere to determine ozone density.

ACE is part of the Canadian SCISAT satellite, which launched in 2003, while OSIRIS is on the Odin satellite, launched in 2001 and is led by Sweden, who partnered with France, Finland and Canada.

Since 2004, scientists have travelled to PEARL to double-check their data.

“One of the challenges of measuring the atmosphere is that it is in constant flux,” says Kaley Walker, professor at the University of Toronto and project lead. “As our PI [principal investigator] of the whole station likes to say, you can’t make measurements for yesterday, today.”

An intensive stay

As both satellites age, it remains important to verify their measurements, said Walker. That’s done during what she calls “this really interesting time of year in the Arctic.”

That’s when the sun comes up in spring and atmospheric dynamics and chemistry create changes in the atmosphere. Ozone is then depleted and trace gases act differently from their usual background-level activity.

The observation period lasts about six weeks, split between the intensive phase (when the whole team is present and instruments are set up) and the extended phase (with fewer scientists and the instruments are more automated).

PEARL’s facilities manager, Pierre Fogal, was one of the few scientists who stayed for the extended phase this year. After his return south, there is now one operator left at PEARL, who will switch out over the year.

Since 2004, the campaign’s six-week study has amassed a lot of valuable data, said Walker.

“A lot of the students are looking at how things have changed over time, so if you have measurements going back to 2004, that 16 year time period allows you to start thinking about how your variations vs. a multi-year trend can be compared,” she said.

To get that information, the team at PEARL uses 11 different instruments. A variety of tools are needed to solve the puzzle that the scientists are working on, because, as Walker said, “the satellite looks through the atmosphere, and so it gets a view sort of sideways, and we’re looking up.”

“It’s a three-dimensional puzzle, and you look at it from one side, and you look at it from the other, it may not have exactly the same view of the puzzle because it’s three dimensional, and so by using the different instruments they get us closer to understanding the three-dimensional nature.”

These instruments require a lot of maintenance, however. That’s why the researchers are looking to increase automation. That way, “our one guy can look after more and more instruments the more automated it is, which then makes our return on investment that much higher,” said Fogal.

A reason to look up

Canada is required to monitor the ozone by the Montreal Protocol, an international agreement to phase out ozone-depleting substances.

But even without those requirements, Fogal said that conducting these atmospheric studies is a valuable practice—and one that could benefit Arctic residents.

While ozone is naturally created and destroyed, it’s important to understand the man-made context within that natural process, said Fogal.

“We also track other pollutants that make it into the Arctic atmosphere from all over the world, the global circulation moves things around quite a lot,” he said.

And Walker, who’s seen forest fire smoke from as far as Siberia pass over Eureka, said that “if it’s getting as far as Ellesmere Island, that stuff is definitely passing over Baffin.”

There’s also the matter of UV rays, which people in Nunavut can be more exposed to during the spring and summer season in years with lower ozone levels.

For Fogal, the pull of the trip is that “it’s work on the frontier, in many senses of the word.”

He’s excited to work in the High Arctic and receive state of the art technology, as well as be on the “edge of discovery.”

Walker is also pulled by the place: “Personally I think that Nunavut is one of the most beautiful, if not the most beautiful, place on the entire planet, so I love going there.”

She also appreciates the trip from a training perspective, bringing students studying atmosphere to the place where they’ll see the impact of their work.

“We’ve had a number who’ve become quite interested in learning more about Nunavut, in making sure that, when we can, we visit communities at lower latitudes than where Eureka is, to make sure that they’re going and talking to people about what we’re doing.”