– par team PAHA* –
Le Laboratoire de recherche atmosphérique dans l’environnement polaire (PEARL) d’Eureka (Nunavut) est un véritable joyau arctique : une station scientifique entièrement équipée pour produire des mesures atmosphériques spécialisées. Il est situé dans le Grand Nord canadien, à seulement 1100 kilomètres du pôle. Le PEARL a officiellement ouvert ses portes en 2006 et dès 2007, il contribuait considérablement à des programmes hautement visibles comme l’Année polaire internationale.
Pourquoi le laboratoire d’Eureka revêt-il tant d’importance?
Premièrement, les conditions atmosphériques physiques et chimiques du site diffèrent notablement de celles qu’on retrouve plus au sud. L’étude de l’atmosphère polaire élargit donc de façon unique notre compréhension de l’atmosphère.
Deuxièmement, le PEARL se trouve dans l’Arctique canadien, qui lui aussi évolue en raison de l’interaction de plusieurs facteurs liés à des activités naturelles et anthropiques.
Troisièmement, nous savons que les changements climatiques évoluent plus rapidement dans l’Arctique qu’ailleurs sur la planète. De plus, l’atmosphère au site du PEARL diffère suffisamment pour justifier tant la recherche à son sujet que la surveillance à long terme de son évolution.
Grâce au financement émanant du gouvernement fédéral, nous poursuivrons l’aventure quelques années encore. Mais nous espérons sincèrement que la recherche dans l’Arctique continuera des années durant. Les enjeux scientifiques associés aux conséquences des changements climatiques et des phénomènes similaires ne peuvent se traiter dans le cadre d’un projet financé durant un seul cycle ou sur la base de quelques années de mesures. Ils doivent faire l’objet d’étude sur plusieurs décennies, et ce, en raison de la responsabilité du Canada en tant que nation arctique et de la protection des ressources arctiques canadiennes.
The Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut is Canada’s “PEARL near the Pole” – a scientific station fully equipped for specialised atmospheric measurements and situated in Canada’s far North only 1,100 km from the Pole.
The original building that houses PEARL was constructed in the early 1990s by what is now Environment and Climate Change Canada, primarily as a location to study ozone, and was named the Arctic Stratospheric Ozone Observatory (ASTRO). Changing priorities at the turn of the century effectively mothballed the facility, but a university and government consortium called the “Canadian Network for the Detection of Atmospheric Change” (CANDAC) pin-pointed measurements of the atmosphere in the Extremely High Arctic as a priority measurement globally, since there are so few measurements at that high a latitude. They also recognized that Canada could provide such a set of measurements to the global community using the Eureka building as a base. Thus was born the idea of PEARL.
With support from numerous funding agencies, including the Canadian Foundation for Climate and Atmospheric Science (CFCAS), Environment Canada, the Canadian Space Agency (CSA), the Natural Sciences and Engineering Research Council (NSERC), and the Canada Foundation for Innovation (CFI), equipment was purchased, and operating funds obtained to focus on improving our knowledge of atmospheric composition and dynamics relevant to global change issues. PEARL was officially opened in 2006 and by 2007 PEARL had become a major contributor to high profile programs such as the International Polar Year (IPY).
When CFCAS funding was not renewed, it looked as though PEARL was destined to close in 2013, but new funds were found in a one-time program from NSERC – the Canadian Climate and Atmospheric Research (CCAR) program, which funded PEARL through the Probing the Atmosphere of the High Arctic (PAHA) network along with six other major environmental networks in the 2013-2018 time frame. However, in 2018, all these networks come to the end of their funding and, despite a highly positive review of the program and requests by NSERC to the government, there is at present no successor program.
Thus, in late 2017 PEARL again faced closure. Some of you will have seen some of the press coverage that flowed from that announcement and the realisation that not only was PEARL ending, but so were the six other major environmental projects of CCAR. NSERC described this as eliminating: “..one of the only sources of public funding for research on climate change and atmospheric processes” (http://www.nserc-crsng.gc.ca/_doc/CCAREvaluation_e.pdf)
On November 8, 2017 the government announced additional funding for PEARL in the amount of $1.6M to carry the facility to the Fall of 2019, by which time we hope that further funding will have been found.
Why is PEARL at Eureka so important? After all, it is in the very far North of Canada over 400 km north of Grise Fiord, which itself is the most northerly community in Canada. It is only accessible by charter plane and has no landlines or fiber for communications. The answer to this question has several facets which we will outline briefly.
Firstly, the atmosphere at these very high latitudes is highly sensitive to the prolonged polar night which lasts from mid-October to mid-February and sets up atmospheric physical and chemical conditions that are extremely different from those at more southerly latitudes. The study of the Polar atmosphere stretches our understanding of the atmosphere in unique ways.
Secondly, PEARL is situated in the Canadian Arctic which itself is changing due to a confluence of several factors linked to natural and anthropogenic activities. PEARL regularly records particulate and chemical intrusions from forest fires, smelters and volcanoes. PEARL also carries out measurements of ozone-related gases and is one of the few High Arctic contributors to the global Network for the Detection of Atmospheric Composition Change (NDACC) network of similar stations.
Thirdly, we know that climate change is occurring faster in the Arctic than in other regions of the planet and again the atmosphere at PEARL is sufficiently different that it merits both research study as well as long-term monitoring of the changes that are occurring. PEARL is one of the few High Arctic contributors to the Total Carbon Column Observing Network which, like NDACC, has stations all over the world but it also an integral part of the calibration systems for the satellites in orbit measuring carbon dioxide over the planet.
Carbon measurements are not the only satellite measurements validated at PEARL, as it is ideally located for overpasses by polar-orbiting satellites. Many of the major atmospheric satellites pass over PEARL frequently, including Scisat and Odin, which carry Canadian instruments optimised for measurements of ozone-related compounds. Every year in February-March there is an intensive campaign at PEARL to make measurements to validate the data from these missions.
PEARL-related research has resulted in more than 25 MSc and PhD theses, with about a dozen others in progress, and more than 125 refereed papers, 340 conference presentations, and 270 workshop presentations. In 2011, PEARL captured the largest ozone depletion event ever seen in the Arctic. This occurred exactly over PEARL, with about 40% of the ozone column destroyed due to the stable vortex and very low temperatures. Measurements by spectrometers and lidar were combined with data from sites in other countries and satellite observations to assemble a comprehensive picture of this phenomenon. Cristen Adams was awarded the CMOS 2012 Roger Daley Post-Doctoral Publication Award and Rodica Lindenmaier the CMOS 2011 Tertia Hughes Memorial Prize for work related to this event. In addition, in 2012 Emily McCullough was awarded the Northern Scientific Training Program Malcolm Ramsay Memorial Award for her lidar work.
PEARL is also invaluable for training young scientists. When you are doing research at PEARL, you are on your own. The nearest Canadian Tire is over 2,000km away and so you need to plan for all contingencies. It promotes self-reliance and a deep understanding of how equipment works. A side benefit is that if there are senior scientists on the site there is a captive mentorship program in the dining hall, and many conversations have gone deep into the night.
PEARL is a collaborative effort. The support of ECCC through the weather station staff and management should be particularly noted, but also the support of the multiple funding agencies that have provided funding in the past – and hopefully will continue to do so into the future.
We also thank the many people who have built equipment for PEARL, operated equipment at PEARL, performed research at PEARL and then gone on to write papers and theses on the research. Many of these people have gone on to research careers in government, academia and industry in Canada and around the world. We also acknowledge all of those who have brought their work to the public through our CANDAC/PAHA education and outreach program, including presentations to more than 2,000 students in over 80 classrooms in Nunavut and southern Canada.
So concludes our short snapshot of our “PEARL at the Pole”. Thanks to funding from the federal government, we will be continuing the journey for another couple of years and we all earnestly hope that the research will continue for many years further. The science questions associated with the impacts of climate change and similar phenomena are not addressed by a project based on a single funding cycle or a few years of measurements; but must be carried out over many decades both as a responsibility of Canada as an Arctic nation and to safeguard Canada’s northern resources.
About the Authors
The Probing the Atmosphere of the High Arctic (PAHA) team consists of:
Jim Drummond, Dalhousie University, Principal Investigator
Kimberly Strong, University of Toronto, Deputy Principal Investigator
Robert Sica, University of Western Ontario
Alan Manson, University of Saskatchewan
Rachel Chang, Dalhousie University
Patrick Hayes, Université de Montréal
Jean-Pierre Blanchet, Université du Québec à Montréal
Kaley Walker, University of Toronto
Norman O’Neill, Université de Sherbrooke