Blowing snow plays an important role in Arctic warming

The Arctic is a hotspot that warms at a rate of nearly four times the global average in a phenomenon known as Arctic amplification. A new study has revealed the important role that tiny aerosols in blowing snow play in this rapid warming.

Aerosols – tiny suspended particles in the atmosphere – were already known to make a significant contribution to the Arctic warming trend, but their precise influence on the climate has remained a mystery.

Focus of the study 

Accumulations of pollutants from distant regions can dramatically alter the atmospheric chemistry of the Arctic. 

These pollutants are proficient at absorbing sunlight and influencing local weather patterns, which in turn triggers localized warming, leading to the melting of ice and snow. Sea salt particles make up the majority of these aerosols. 

Dr. Jian Wang, who heads the Center for Aerosol Science and Engineering (CASE) and serves as a professor at Washington University in St. Louis, led a comprehensive investigation into the mysteries of sea salt aerosols. 

Blowing snow 

The study has revealed that blowing snow significantly increases the concentration of fine sea salt aerosol particles, which in turn influences cloud formation in the region.

“Over the past few decades, scientists have identified ‘Arctic haze’ as the primary source of aerosols in the Arctic during winter and spring. This haze results from the long-range transport of pollutants,” said study first author Dr. Xianda Gong.

“However, our study reveals that local blowing snow, which produces sea salt particles, contributes a more substantial fraction to the total aerosol population in the central Arctic.”

How the research was conducted 

The team used data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), an initiative that involved embedding an icebreaker in the central Arctic ice pack, allowing it to drift with the sea ice for a full year. 

“The MOSAiC expedition let us observe how aerosols and clouds evolve over the course of a year and led to this discovery,” said Wang. 

“Sea salt particles in the Arctic atmosphere aren’t surprising, since there are ocean waves breaking that will generate sea salt aerosols. But we expect those particles from the ocean to be pretty large and not very abundant. We found sea salt particles that were much smaller and in higher concentration than expected when there was blowing snow under strong wind conditions.”

What the researchers learned 

Clouds, it seems, play a pivotal role in the Arctic’s warming phenomenon. On the clearest and coldest of Arctic winter nights, Earth’s heat can dissipate into the cosmos. However, under the protective canopy of clouds, this longwave radiation is ensnared, leading to warming. 

Small aerosol particles, such as the ones thrown up by blowing snow, are adept at encouraging cloud formation. 

“These sea salt particles can act as cloud condensation nuclei, leading to cloud formation,” said Gong. “Considering the absence of sunlight in the winter and spring Arctic, these clouds have the capacity to trap surface long-wave radiation, thereby significantly warming the Arctic surface.”

Sea salt aerosols 

Although these findings may seem surprising, the presence of fine sea salt aerosols from blowing snow has always been integral to the Arctic’s climate dynamics. 

The study has shown that these particles account for approximately 30% of all aerosol particles. With this revelation, climatologists can fine-tune their models for greater accuracy.

“Model simulations that don’t include fine sea salt aerosols from blowing snow underestimate aerosol population in the Arctic,” said Wang. 

“Blowing snow happens regardless of human warming, but we need to include it in our models to better reproduce the current aerosol populations in the Arctic and to project future Arctic aerosol and climate conditions.”

The study is published in the journal Nature Geoscience.

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

—–

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.