Although climate change is currently affecting our entire planet, the Arctic region is feeling its effects the most, in the form of glacial melt, permafrost thaw, and sea ice decline. Key players in Arctic warming include clouds and microscopic aerosols called ice nucleating particles which seed the formation of ice in the clouds.
Until recently, these ice-creating aerosols – which include mineral dust, microbes, or sea spray – have not been extensively studied in the Arctic. However, a team of researchers led by Colorado State University (CSU) has sailed to the Arctic in 2019 and gathered thousands of air, seawater, sea ice, snow, and meltwater samples in order to investigate how ice nucleation and clouds over the Arctic Ocean evolve over time.
“It is important to know the natural background of these ice nucleating particles before we can really assess how changes due to climate are affecting the populations of these aerosols,” said study lead author Jessie Creamean, an expert in Atmospheric Science at CSU. By observing how ice nucleating particles in the central Arctic evolve during the entire annual sea ice growth and decline cycle, the scientists found that these particles are characterized by a strong seasonality, with lower concentrations in the winter and spring, and higher concentrations during the summer melt, most likely from marine biological production in local open waters.
Clarifying the dynamics of these ice nucleating particles is fundamental for understanding the effects of climate change on our planet. Since adding ice to clouds – a process in which these particles play a critical role – changes how clouds interact with light and heat coming from the sun or bouncing back from the Earth’s surface, the ways in which the particles fluctuate over the seasons influence global warming.
“It’s an important process we just don’t have a good understanding of, especially in the Arctic. The models just don’t get it right when it comes to estimating these ice nucleating particles or their cloud effects. So, this was a big observation – to have a look at where these things are coming form, and how they change over the course of a year,” Dr. Creamean concluded.
The study is published in the journal Nature Communications.