A new study conducted by researchers at the Institute of Polar Sciences of the National Research Council of Italy, in collaboration with Stockholm University and ETH Zurich, has identified the mechanisms that control the Arctic transport of black carbon, an air pollutant that contributes to climate warming, while also establishing the variability of its concentrations across polar seasons. The work lays the groundwork for a deeper understanding of the impact of this compound on regional and global climate.
Black carbon is an atmospheric pollutant, able to contribute to global warming and is also present in the Arctic. In this polar region, its concentration depends on several mechanisms that control its transport from mid-latitudes, where most of the sources are located. These mechanisms have now been unveiled by researchers at the Institute of Polar Sciences of the National Research Council of Italy (Cnr-Isp) who, in collaboration with Stockholm University and ETH Zurich, have been continuously measuring the concentration of black carbon in the Arctic for more than four years, studying how its concentration changes over time.
“This compound, produced by human activities and fires in the mid- and low-latitudes, can remain for a long time in the atmosphere and can reach the Arctic region, where it contributes to atmospheric warming and accelerates melting of snow and ice,” explains Stefania Gilardoni, Cnr-Isp researcher and author of the paper. “Current models cannot reproduce the temporal variability of black carbon in the Arctic, making it difficult to predict its impacts on climate warming at regional and global scales.”
The research, funded by the Italian Ministry of Universities and Research’s Program for Research in the Arctic (PRA) and carried out with support from the Svalbard Integrated Observing System (SIOS) network, used a machine learning model, or artificial intelligence technique, to help analyze measurements collected at the atmospheric observatory in Gruvebadet, Svalbard Islands. “We measured the atmospheric concentration of black carbon continuously, during both polar day and night, starting in 2018 and for more than four years, observing that black carbon concentrations show strong seasonal variability, with higher values between December and April,” continues Mauro Mazzola, study co-author and Cnr-Isp researcher. “We found that this variability depends on the frequency and intensity of rainfall, which is the highest between May and November, a period when black carbon concentrations are lowest, as rainfall effectively removes this compound from the atmosphere before it can reach the polar regions.” Within the same season, the researchers also found differences in black carbon concentrations that depend on temperature and meteorological phenomena. “During the cold season (November – April), the highest concentrations of black carbon are observed when temperatures are lower and correspond to the transport of cold air masses from northern Europe and Siberia” Gilardoni points out. “While, during the warm season (May – October), the highest concentrations of black carbon occur during winds that transport polluted air from warmer regions.” “This study demonstrates the high scientific value of the Gruvebadet atmospheric observatory, where the Italian research has been engaged for more than 10 years, because this site is representative of atmospheric processes occurring on a spatial scale ranging from hundreds to thousands of kilometers” the paper’s authors conclude. In addition, “the results collected will provide new data to climate and transport models useful for understanding how changes in weather patterns and atmospheric circulation, triggered by climate change, will impact the concentration of black carbon in the Arctic on regional and global climate.”
