Recently, Professor Tian Wenshou’s research team from the College of Atmospheric Sciences at Lanzhou University published a groundbreaking study in the prestigious journal Geophysical Research Letters, titled “Stratospheric Polar Vortex Exerts Different Controls on the Transport of Tropical and Mid-Latitude Volcanic Aerosols”. The study systematically evaluated the efficiency of aerosol transport from various volcanic events to the polar regions, revealing critical transmission mechanisms. It highlights the urgent need to monitor extreme ozone hole risks and their concurrent climate impacts following mid-latitude volcanic eruptions during summer, providing crucial scientific evidence for optimizing future geoengineering strategies.
How do volcanic aerosols cross hemispheres and finally reach the polar regions?
In recent years, small and medium-sized volcanic eruptions and extreme wildfire events have injected a large amount of aerosols into the stratosphere, exerting a profound impact on global climate and the ozone layer. Based on satellite observation data and CESM Earth system model simulation, this study found that approximately 67% of the stratospheric aerosols in Antarctica over the past 20 years may have originated from volcanic and extreme wildfire emissions in the mid-low latitudes (Figure 1). In addition, the efficiency of aerosols from different volcanic events entering the polar regions varies several times, and the academic community has not yet fully clarified the underlying mechanism.
Figure 1: (a-e) Aerosol distribution observed by multiple satellites; (f) Content and sources of Antarctic aerosols; (g) The efficiency of aerosol transmission from satellite observations to the South Pole
Differences in the paths of volcanic aerosols entering the South Pole:
Aerosols emitted by tropical volcanoes take a longer time to reach the polar boundaries. In winter, they are blocked by polar vortices and cannot directly enter the Antarctic region. They must wait for the polar vortex in the Southern Hemisphere's spring (September to November) to weaken or even collapse before they can "take the opportunity to enter" and enter the polar airspace in large numbers. This makes the aerosol content in Antarctica in October mainly regulated by the interannual variability of polar vortices.
The influence of mid-latitude volcanoes is more dependent on the season of their eruption. If it occurs in summer and autumn, aerosols can "board" the stratospheric BD circulation, gradually approaching the polar regions, crossing the lower part of the polar vortex and "sneaking" into the South Pole. If the eruption occurs during the winter when the polar vortex is strong, the aerosol will also face the situation of being "shut out" by the polar vortex.
Figure 2: Polar transport mechanism and efficiency of tropical and mid-latitude volcanic aerosols in different seasons
From "Blocker" to "Regulator" :
The dynamic role of the polar vortex
Through multiple sets of sensitivity simulations, this study further quantified the efficiency of aerosols from volcanic events entering the polar regions at different latitudes and seasons, clearly indicating that the polar vortex is not a single barrier but a dynamic regulator with the function of "screening" aerosol emissions based on latitude and season. This discovery not only helps to enhance our understanding of the potential impact of future natural events (such as volcanic eruptions and wildfires) on global climate and the ozone layer, but also provides a key reference for safer and more precise SAI strategies. For instance, injecting aerosols in specific seasons and latitudes may help reduce the impact of ozone and enhance the efficiency of climate intervention.
Furthermore, the first author of this paper has previously published in Geophysical Research Letters (Peng et al., 2023) and Journal of Geophysical Research: Two related studies were published in "Atmospheres" (Peng et al., 2024), systematically exploring the coupling effect of aerosols caused by volcanic eruptions in chemical-radiation-dynamic processes:
Research indicates that in large-scale volcanic eruptions, the influence of gas-phase chemistry on stratospheric ozone even exceeds that of the traditionally believed dominant heterogeneous chemical processes, suggesting that the role of gas-phase chemistry in ozone changes after volcanic disturbances is significantly underestimated. From the perspective of sulfur dioxide emissions, The relative importance of gas-phase chemistry, heterogeneous chemistry and atmospheric dynamic processes was quantified (Peng et al., 2023). Furthermore, the study diagnosed the cause of the "weak aerosol radiation effect" in mid-high latitude volcanic eruptions, pointing out that this phenomenon cannot be explained merely by the shorter aerosol lifetime, but is closely related to the lower aerosol radiation efficiency (Peng et al., 2024).
The above achievements are organically connected with the GRL paper published this time. From the transmission path of aerosols and their combined effects in radiation, chemical and dynamic processes, it deepens the systematic understanding of the climate effects of stratospheric aerosols, laying a solid scientific foundation for the design and evaluation of future geoengineering.
This paper was completed under the joint guidance of Professor Tian Wenshou from Lanzhou University and Professor Yu Pengfei from Jinan University. The first author is Peng Yifeng, a 2022 doctoral student at the College of Atmospheric Sciences, Lanzhou University. This research was supported by the National Key Research and Development Program of China (2024YFF0808501), the National Natural Science Foundation of China (42475084,42121004, 42175089), and the Basic Research Project of the Central Universities (561224003).
Paper Information:
Peng, Y., Tian, W., Liu, C.-C., & Yu, P*. (2025). Stratospheric polar vortex exerts different controls on the transport of tropical and mid-latitude volcanic aerosols. Geophysical Research Letters, 52, e2025GL116525.
Peng, Y., Tian, W*., Li, C., Xue, H., & Yu, P*. (2024). Distinct radiative and chemical impacts between the equatorial and northern extratropical volcanic injections. Journal of Geophysical Research: Atmospheres, 129(20), e2024JD041690.
Peng, Y., Yu, P.*, Portmann, R. W., Rosenlof, K. H., Zhang, J., Liu, C. C., Li. J., Tian. W. (2023). Perturbation of tropical stratospheric ozone through homogeneous and heterogeneous chemistry due to Pinatubo. Geophysical Research Letters, 50(16), e2023GL103773.
