SAGE II and SAGE III/ISS inference of the optical perturbations caused by volcanic eruptions

An analysis of multiwavelength stratospheric aerosol extinction coefficient data from the Stratospheric Aerosol and Gas Experiment II and III/ISS instruments by Thomason et al. (2021) demonstrated a coherent relationship between the perturbation in extinction coefficient in an eruption’s main aerosol layer and the wavelength dependence of that perturbation. The relationship was observed to span multiple orders of magnitude in the aerosol extinction coefficient of stratospheric impact of volcanic events. Since that publication, the 2022 eruption by Hunga Tonga-Hunga Ha’apai is noted for several unique features including its intensity and altitude of the aerosol injection. It is also among the largest eruptions since the 1991 eruption by Mt. Pinatubo. In this paper, we show that this eruption fits well into the extinction coefficient/extinction coefficient ratio space found in the previous publication. In addition, while the previous publication was focused on the peak extinction coefficient following the eruption, herein we examine how well the spatial distribution of enhanced aerosol extinction follows the simple relationship between extinction coefficient and extinction coefficient for the by Hunga Tonga-Hunga Ha’apai  eruption and those previously examined.

Thomason, L. W., Kovilakam, M., Schmidt, A., von Savigny, C., Knepp, T., and Rieger, L.: Evidence for the predictability of changes in the stratospheric aerosol size following volcanic eruptions of diverse magnitudes using space-based instruments, Atmos. Chem. Phys., 21, 1143–1158, https://doi.org/10.5194/acp-21-1143-2021, 2021.