EGU23-5788, updated on 19 Sep 2024
https://doi.org/10.5194/egusphere-egu23-5788
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Stratospheric aerosol size decrease after volcanic eruptions

Felix Wrana1, Ulrike Niemeier2, Sandra Wallis1, and Christian von Savigny1
Felix Wrana et al.
  • 1Institute of Physics, University of Greifswald, 17489 Greifswald, Germany (felix.wrana@uni-greifswald.de)
  • 2Max Planck Institute for Meteorology, 20146 Hamburg, Germany

The evolution of the size distribution of stratospheric aerosols after volcanic eruptions is still not understood very well, due to the temporal sparsity of in situ measurements, the low spatial coverage by ground based observations and the difficulties to derive aerosol size information from satellite measurements. To contribute to this ongoing research, we show data from our aerosol size retrieval using SAGE III/ISS solar occultation measurements. Using a three wavelength extinction approach the parameters of assumed to be monomodal lognormal particle size distributions are retrieved.

Surprisingly we find that some volcanic eruptions can lead to a decrease in average stratospheric aerosol size, in this case the eruptions of Ambae in 2018, Ulawun in 2019 and La Soufrière in 2021, while other eruptions have a more expected increasing effect on the average particle size, like the 2019 Raikoke eruption. We show how different parameters like the median radius, the absolute mode width and the number density evolve after the mentioned eruptions.

Additionally, as a part of our ongoing research to understand the underlying mechanisms controlling the observed aerosol size reduction, we show simulations of the aforementioned volcanic eruptions using the aerosol-climate model MAECHAM5-HAM. Although the initial conditions in the model simulations are different from observations due to missing smaller emissions in the time before the eruptions, a good agreement in the perturbations of the extinction coefficient was achieved.

How to cite: Wrana, F., Niemeier, U., Wallis, S., and von Savigny, C.: Stratospheric aerosol size decrease after volcanic eruptions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5788, https://doi.org/10.5194/egusphere-egu23-5788, 2023.