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Atmospheric scientists discover sea salt particles in blowing snow play a significant role in creating clouds linked to increased warming in the Arctic

Scientists studying Arctic warming have found that tiny sea salt aerosols from blowing snow play a key role in forming clouds that trap terrestrial radiation and send energy back to the Earth's surface, contributing significantly to warming in the region.

The finding, published in Nature Geoscience, is part of the scientific effort to understand why Arctic air temperatures are increasing nearly four times faster than the global average. A lack of understanding of Arctic clouds means they are currently poorly represented in climate models.

Clouds form around aerosol particles, such as dust, soot and sea salt. Existing models for cloud formation and their properties assume that sea salt aerosols are low in concentration – implying that they don't have a significant impact on cloud formation or their properties.

To test that theory, a team of atmospheric scientists from Dalhousie University, Washington University in St. Louis and other institutes measured aerosols in the central Arctic from September 2019 to October 2020, observing sea salt aerosol-producing conditions 20 per cent of the time in the winter months when there was only ice and no breaking waves.

The team, which gathered the data by trapping a German research icebreaker in Arctic sea ice for a year as part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, now estimates that sea salt aerosols account for almost 30 per cent of the particles for cloud condensation through winter and spring.

Betty Croft and Rachel Chang in Dalhousie's Department of Physics and Atmospheric Science were part of the team and are available to discuss how this work will improve climate models by allowing scientists to be more precise about the impact of pollution by humans.

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Media contact:
Alison Auld 
Senior Research Reporter 
Communications, Marketing and Creative Services 
Dalhousie University 
Cell: 1-902-220-0491 
Email: alison.auld@dal.ca