USask PhD candidate Kimberlee Dube. (Photo: Submitted)
USask PhD candidate Kimberlee Dube. (Photo: Submitted)

USask researcher helps to protect Earth’s atmosphere by interpreting satellite data

If you look up at the night sky, there’s a chance you are gazing directly at the Odin satellite—home to the University of Saskatchewan (USask)-designed Optical Spectrograph and InfraRed Imaging System (OSIRIS) instrument.

USask College of Arts and Science PhD candidate Kimberlee Dube works directly with the data OSIRIS and other satellite instruments collect to analyze changes to Earth’s atmosphere. These changes can have significant impacts on life on Earth. 

“The goal of my research group is to understand how the atmosphere is changing. We focus on the middle atmosphere, from about 10-50 kilometres above the Earth (the stratosphere),” said Dube.  

“We care about this region of the atmosphere because it’s home to the ozone layer that protects us by absorbing ultraviolet (UV) radiation.” 

The stratosphere is greatly affected by activities on Earth, such as wildfires and volcanic eruptions that release small particles into the air, she said. These particles, called aerosols, have the potential to block sunlight reaching the Earth and cool the atmosphere to unsustainable levels. Human-made pollution also can cause chemical changes in the stratosphere that could result in similar negative effects. 

To study the effects of different events on the stratosphere and to map changes over time, Dube’s Department of Physics and Engineering Physics research team uses myriad tools and techniques to collect data from the zone. 

“My research group designs and builds instruments that go on stratospheric airplanes, balloons and satellites,” said Dube. “These measure important parameters like ozone, aerosol, nitrogen dioxide (NO2), or water vapor concentrations.”  

The increase in NO2 is a recent concern for scientists studying the ozone layer. Since greenhouse gas emissions have been largely reduced by environmental protection protocols, NO2 has become the largest contributor to ozone depletion.  

Potential effects of ozone destruction from increasing NO2 include harm to plants and animals, and increased incidences of diseases such as skin cancer from higher UV radiation. 

Satellites have been measuring NO2 concentrations in the atmosphere since the 1980s, but complicated chemistry makes the data hard to use in scientific studies, said Dube. 

“Nitrous oxide (N2O) is emitted by many human activities, in particular the use of nitrogen fertilizers in agriculture,” she said. “Once N2O gets into the stratosphere, it is converted to NO2 that destroys ozone. Therefore, it is important to know what is happening with NO2 in the stratosphere to understand what is happening with the ozone layer.” 

Part of her research focuses on improving the data record so measurements made by using instruments such as OSIRIS can be interpreted more accurately in research. Her data demonstrated that NO2 levels in the stratosphere have indeed been increasing. 

Dube has found both publication and presentation success throughout her doctorate program, with publications in major journals such as the Journal of Geophysical Research and the opportunity to share results with the National Aeronautics and Space Administration (NASA) at the annual Stratospheric Aerosol and Gas Experiment (SAGE) III/International Space Station science team meeting. 

She has engaged in numerous research collaborations with others in the field, including researchers from the National Center for Atmospheric Research in Boulder, Colo. 

“I have always been interested in the weather and climate. It’s interesting to learn about the physics and chemistry behind these processes,” said Dube. “My research has resulted in NO2 data that better represent what is actually happening in the atmosphere.” 

Funding for the research has been provided by the Canadian Space Agency and the Natural Sciences and Engineering Research Council of Canada. 

This article first ran as part of the 2022 Young Innovators series, an initiative of the USask Research Profile and Impact office in partnership with the Saskatoon StarPhoenix.

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