New insights into the formation of tiny particles in marine air which ultimately impact cloud, weather and climate

Professor O’Dowd, Director of the Centre for Climate & Air Pollution Studies in the School of Physics and Ryan Institute at NUI Galway.
Sep 22 2016 Posted: 14:08 IST

Research published in today’s issue of Nature has provided new insights into the formation of tiny particles in marine air which ultimately have an impact on cloud formation, weather patterns and global climate. The international team, which included the National University of Ireland (NUI) Galway’s Professor Colin O’Dowd and Dr Darius Ceburnis, gathered data from field stations on the west coast of Ireland, Greenland and the Antarctic.

Atmospheric aerosols are tiny airborne liquid or solid droplets or particles, ranging from nanometers to tens or even hundreds of microns in size”, explains Professor O’Dowd, Director of the Centre for Climate & Air Pollution Studies in the School of Physics and Ryan Institute at NUI Galway. “They essentially act as condensation sites for water vapour leading to the formation of haze and cloud layers which ultimately help to keep the earth system from overheating. They do this by reducing the amount of solar energy passing through the atmosphere and absorbed by the Earth.

An increase in the abundance of these tiny particles leads to more reflective haze and cloud layers. The end result of more reflecting haze and cloud layers is to partially offset the degree of global warming by greenhouse gases.”

Professor O’Dowd continued: “For the first time, we have measured, at a molecular level the nucleation, or formation mechanism and the nucleating molecules forming these tiny particles, less than a nanometer (a thousand of a millionth of a meter in size), in marine air. Our experiments reveal that the formation and initial growth process is almost exclusively driven by iodine oxoacids and iodine oxide vapours and that cluster formation primarily proceeds by sequential addition of HIO3, followed by intracluster restructuring to I2O5 .

These observations will help us understand the feedbacks between the marine biosphere and global climate change. The Mace Head atmospheric research station was the key experimental or ‘atmospheric laboratory’ facility leading to the new discovery.”

Professor O’Dowd was recently award the Mason Gold medal by the Royal Meteorological Society, the Royal Irish Academy and the Appleton Medal by the Institute of Physics for his research into atmospheric composition and climate change. He is also ranked among the ‘World’s Most Influential Scientific Minds’ by Thomson Reuters.

The full paper ‘Molecular-scale evidence of aerosol particle formation via sequential addition of HIO3’ is published in today’s edition of Nature, with co-authors from: University of Helsinki, Helsinki, Finland; Leibniz-Institute for Tropospheric Research (TROPOS), Germany; University of Eastern Finland, Finland; Aerodyne Research Inc., USA; and the Finnish Meteorological Institute, Finland.


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