By David Shukman
Polar Environment Atmosphere Research Laboratory, Canada
Pearl should help reveal vital clues about our changing planet
Perched on a windswept ridge amid the fjords and mountains of Ellesmere Island stands one of the world's northernmost atmospheric research stations - a rugged outpost of frontline science with the delicate name of Pearl.
Pearl stands for Polar Environment Atmosphere Research Laboratory and the scientists braving the elements here believe that in coming years it should help reveal vital clues about our changing planet.
The lab is reached by a bumpy, icy track that climbs up from the weather station at Eureka. The view over a frozen inlet and out to distant peaks is startling.
Equipped with as many as 27 different instruments, it's designed to provide the most comprehensive view yet of the state and composition of the Arctic air from ground-level up to the edge of space.
According to project manager Pierre Fogal, Pearl should produce invaluable data on the key questions of our time.
"There's a danger with global warming that we think we don't need to do any more science on it - when in fact we do need a much more complete understanding of what's happening," he told me.
Originally set up in the early 90s, the lab struggled with a lack of funding and at one stage was destined to be shut down.
Prof Drummond explained that CFC monitoring was vital
Now the lab is supported by a consortium of Canadian universities, with backing from the Canadian government and its work is seen as a major element of International Polar Year.
One of the leading scientists involved is Professor Jim Drummond of the University of Toronto.
On our visit, he led me up onto the roof to see the range of instruments at work in the freezing Arctic air.
"There are three key issues we can investigate here which are relevant to everyone - the state of the ozone, the quality of the air, and climate change," he says.
'Place of significance'
He shows me the device that monitors UV light reaching the surface. According to Professor Drummond, the Montreal Convention banning the use of the CFC gases which destroy the ozone layer will only work if it is properly policed - and that requires careful long-term monitoring.
The air quality is assessed by examining the concentrations of different gases including the greenhouse gas carbon dioxide and the levels of aerosols, the tiny particles carried in pollution.
Experiments monitor the pollution that makes its way north
Exhaust fumes and chimney smoke from the cities and factories of Europe, America and Asia all make their way North and the pattern of the winds mean that most of them stay.
The Arctic may be remote and look pristine but it has become an industrial dustbin.
Most instruments have only been running for a year or so. But already one has observed a previously unknown pattern of winds in the upper atmosphere.
The aim is for most of the data to be gathered autonomously and transmitted back to the researchers further south.
As we leave we notice a small cairn a short distance away. It is what the Inuit people call an Inukshuk - a structure of stones marking a place of significance.
That's certainly the hope of the researchers operating this sentinel in the Arctic. As we descend I turn for a final look - but Pearl is hidden in a cloud.