SMuK 2021 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 2: Clouds and Aerosols
UP 2.7: Vortrag
Donnerstag, 2. September 2021, 15:40–15:55, H3
Satellite observations of volcanic eruptions leading to smaller average stratospheric aerosol sizes — •Felix Wrana1, Christian von Savigny1, and Larry W. Thomason2 — 1Institut für Physik, Universität Greifswald, Greifswald, Germany — 2NASA Langley Research Center, Hampton, Virginia, USA
We present surprising results of our stratospheric aerosol size retrieval which is using the SAGE III/ISS solar occultation measurements, that started in 2017. Due to the broad wavelength spectrum covered by the instrument a robust and simultaneous retrieval of the median radius and mode width of monomodal lognormal size distributions is possible. We focus on three small to mid-intensity volcanic eruptions that were observed by SAGE III/ISS and that reached and perturbed the stratospheric aerosol layer: The Ambae eruptions (15.3°S) in spring of 2018 and the Raikoke (48.3°N) and Ulawun (5.05°S) eruptions, both in June 2019. While the Raikoke eruption led to an increase in the median radius of the stratospheric aerosols, which was to be expected and is in line with previous observations, the Ambae and Ulawun eruption had the opposite effect. After both eruptions the average aerosol size decreased, with lower median radii and narrower size distributions, while the number density increased strongly. The observation that volcanic eruptions may lead to smaller average stratospheric aerosol sizes, as also recently discussed by Thomason et al. (2021), is a novel one and should be of great interest to the modeling as well as remote sensing community. In our talk, we will present the temporal and spatial evolution of the size distribution parameters.