The evolution and dynamics of the Hunga Tonga–Hunga Ha'apai sulfate aerosol plume in the stratosphere

Abstract

Abstract. We use a combination of spaceborne instruments to study the unprecedented stratospheric plume after the Tonga eruption of 15 January 2022. The aerosol plume was initially formed of two clouds at 30 and 28 km, mostly composed of submicron-sized sulfate particles, without ash, which is washed out within the first day following the eruption. The large amount of injected water vapour led to a fast conversion of SO2 to sulfate aerosols and induced a descent of the plume to 24–26 km over the first 3 weeks by radiative cooling. Whereas SO2 returned to background levels by the end of January, volcanic sulfates and water still persisted after 6 months, mainly confined between 35∘ S and 20∘ N until June due to the zonal symmetry of the summer stratospheric circulation at 22–26 km. Sulfate particles, undergoing hygroscopic growth and coagulation, sediment and gradually separate from the moisture anomaly entrained in the ascending branch Brewer–Dobson circulation. Sulfate aerosol optical depths derived from the IASI (Infrared Atmospheric Sounding Interferometer) infrared sounder show that during the first 2 months, the aerosol plume was not simply diluted and dispersed passively but rather organized in concentrated patches. Space-borne lidar winds suggest that those structures, generated by shear-induced instabilities, are associated with vorticity anomalies that may have enhanced the duration and impact of the plume.

Unexpected self-lofting and dynamical confinement of volcanic plumes: the Raikoke 2019 case

“…As the PV gradient across the tropopause and the Coriolis factor, both increasing towards the poles (Fig. S7 ), are likely the key factors of the VVP formation, the tropical volcanic eruptions are much less likely to produce a self-confined anticyclone 41 . Moreover, since the internal heating of the plume aids in stabilizing the anticyclone, the absorbing properties of the emitted aerosols is another key factor.…”

Using OMPS-LP color ratio to extract stratospheric aerosol particle size and concentration with application to volcanic eruptions

“…Reikoke (48.29 °N, 153.25 °W) erupted on June 21, 2019, and injected materials to a height of 17-19 km (Muser et al, 2020;Gorkavyi et al, 2021). There is also evidence that the plume continued to self-loft after the eruption, reaching 27 km altitude (Khaykin et al, 2022). Figure 6c and 6d show the distribution of aerosols for a 30-day period following the eruption.…”

“…Ash and dust mostly consist of larger particles that can settle out of the stratosphere within a few days. Smoke, dust and ash can provide condensation nuclei for sulfuric acid, forming dark aerosols that have been observed to 'self loft' due to solar heating (Yu et al, 2019, Khaykin et al, 2020, Khaykin et al, 2022.…”

“…On the other hand, the limb scattering radiances are more complicated to interpret and have higher uncertainty due to variations in the scattering angle with orbit, variation in scattering properties with particle size, and measurement contamination by surface reflected light. Yet, despite these drawbacks, the limb scattering techniques have provided new insights into the rapid evolution of stratospheric aerosols especially immediately following volcanic eruptions (Taha et al, 2022, Khaykin et al, 2022, Wells et al, 2022.…”

Tomographic Retrievals of Hunga Tonga‐Hunga Ha'apai Volcanic Aerosol

“…Geostationary satellite imagery shows the early plume in the uppermost levels of the stratosphere at a record‐breaking altitude of 58 km (Carr et al., 2022). The highest reaches of the plume, mostly composed of ice, sublimated rapidly in the warm temperatures of the upper stratosphere (Khaykin et al., 2022), with the main plume descending rapidly to be below 30 km since early February (Legras et al., 2022). A truly remarkable feature of this eruption is the large amount of water vapor in the plume, which satellite measurements show accounts for an increase of 10%–13% in the global stratospheric water vapor mass (Khaykin et al., 2022; Millán et al., 2022), although work using balloon sondes estimates a value closer to 5% (Vömel et al., 2022).…”