Mean aerosol optical depth (AOD) for spring (April–May) and summer (June–August) derived from satellite observations with the AEROSNOW retrieval. Source: Marco Vountas, Uni Bremen
For the first time, reliable satellite measurements of aerosol concentrations over Arctic sea ice are possible
Leipzig, 12.06.2026 – Bernd Heinold / Tilo Arnhold
study in the open-access journal npj Clean Air
The Arctic is warming twice as fast as the rest of the Earth. In addition to greenhouse gases, aerosols—tiny particles in the air—also play an important role. They influence the climate by scattering sunlight and altering cloud formation.
An international team of researchers has used satellite remote sensing to investigate the actual quantity of aerosol particles present above the Arctic sea ice and how they attenuate sunlight. Until now, very little was known about this, as satellite measurements are extremely difficult to carry out over the highly reflective surface of snow and ice. The new satellite observations were used for a comprehensive evaluation of 16 climate models, revealing a significant underestimation of the simulated transport of air pollutants from mid-latitudes to the Arctic – an important step towards improving these models in the future.
The study, which was published in the open-access journal npj Clean Air by Nature Springer, involved researchers from the Universities of Oxford and Bremen, as well as the Max Planck Institute for Chemistry, TROPOS and the German Aerospace Centre (DLR). The research forms part of the Collaborative Research Centre/Transregional Research Network ‘Arctic Amplification (AC)³’, which has been funded by the German Research Foundation since 2006. The research consortium’s final meeting will take place from 8 to 12 March 2027 as part of the Joint (AC)3 – MOSAiC Conference (JAMC27; www.jamc27.com) at the University of Leipzig.
Scientists at the IUP in Prof. Bösch’s department (formerly Prof. Burrows’ department) have developed a method called AEROSNOW, which for the first time enables reliable satellite measurements of aerosol concentration (measured as “Aerosol Optical Depth,” AOD) over Arctic sea ice—covering nearly a full decade (2003–2011).
The measurements show a clear seasonal pattern:
Spring (April–May): Elevated aerosol levels (AOD ~0.08–0.18), particularly at the ice edges near Canada, Alaska, and Siberia. This is the well-known “Arctic haze”—caused by the transport of pollutants from mid-latitudes to the Arctic. Summer (June–August): Significantly cleaner air (AOD ~0.05–0.07) due to heavier rainfall and reduced transport of pollutants.
The researchers compared the AEROSNOW measurements with simulations from 16 different climate models (CMIP6). The results are sobering. Most models underestimate Arctic haze: 12 out of 16 models underestimate spring aerosols by 40–75%. They simulate too little particle transport from mid-latitudes to the Arctic
Read more at the news of the Universität Bremen:
Publikation:
Swain, B., Vountas, M., Singh, A. et al. Large inter-model spread in simulated aerosol load over Arctic sea ice. npj Clean Air 2, 37 (2026). https://doi.org/10.1038/s44407-026-00080-7