Thanks to Canada’s SCISAT, an international team of scientists has discovered a recent and unexpected increase in stratospheric hydrogen chloride (HCl) in the Northern Hemisphere.

Information from SCISAT along with other satellite data and ground-based measurements showed the scientific team that the increase in stratospheric HCl is due to a slowdown in the atmospheric circulation of the Northern Hemisphere. This discovery could impact how scientists will analyze the evolution of the stratospheric ozone layer going forward.

Since 1989, the implementation of the UN’s Montreal Protocol has led to a reduction in chlorofluorocarbons (CFCs) around the globe. These CFCs are responsible for the depletion of the ozone layer that protects us from ultraviolet radiation. CFCs break-up in the stratosphere and release chlorine atoms that then form HCl. Under certain conditions, HCl can be transformed into other chlorine-containing molecules that destroy ozone.

Quick facts

– SCISAT, a Canadian-led mission managed by the Canadian Space Agency, launched in 2003, with the objective of measuring the amount of ozone and related molecules in the Earth’s atmosphere.

– The satellite’s measurements also contribute to improving our understanding of atmospheric chemistry which affects air quality over Canada, including the Arctic.

– This space data is useful for validating Canada’s Air Quality Health Index and UV Index.

– SCISAT has become internationally known as the satellite that provides measurements of over 40 atmospheric constituents. ABB Inc. developed the ACE-FTS instrument while Bristol Aerospace Ltd. (now Magellan Aerospace Corporation) built the satellite bus. SED Systems is responsible for the satellite operations. Professor Peter Bernath of the University of Waterloo is the Principal Investigator for the mission. Dr. Kaley A. Walker of the University of Toronto is the Co-Investigator.

Quotes
“The SCISAT data was essential in identifying the altitudes at which this change was taking place. Without reliable HCl measurements in the lower stratosphere provided by the Canadian instrument, we could not have reached this conclusion. No other single instrument has provided such a wide range of data products for such a long time”

– Peter Bernath, University of Waterloo chemist and Principal Investigator of the ACE-FTS instrument

“Originally, the instrument was designed to study ozone and molecules involved in ozone production and destruction. Now, we’ve developed further data products that have allowed us to contribute in so many other areas”

– Kaley A. Walker, chemical physicist at the University of Toronto

“The instrument turned out to be an enormous commercial success for us, as well as a scientific success for Canadian researchers. We really hit a home run with it. The $20M Canada invested in the instrument materialized into more than $100M in sales. It’s quite remarkable – the whole team deserves credit for its success.”

– Marc-Andre Soucy, Director for the Remote Sensing Industry at ABB Inc.

Additional links

The Canadian Space Agency’s webpage on SCISAT and the ACE-FTS instrument
Nature article