| Popis: |
The stratospheric aerosol layer has witnessed large perturbations in the last couple of years. From extreme wildfires in North America and Australia to medium-size volcanic eruptions like Ambae, in July 2018, Raikoke, in 2019, and finally the Hunga-Tonga Ha’apai in January 2022. Reported as the largest marine eruption ever recorded, researchers used Microwave Limb Sounder (MLS) satellite data to reveal that this volcano injected the equivalent of 10% of the total stratospheric water vapor content (100 Tg) into the stratosphere. As a consequence, increased OH radicals from water vapor were reported to further reduce the SO2 lifetime by 50%.Here we outline the ionic composition, in parallel with microphysical, chemical, and optical properties of stratospheric aerosols using balloon measurements from Brazil 5-7 months after the eruption, in comparison with satellite data and model simulations. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and ground-based lidar measurements revealed the existence of a volcanic plume between 20 and 25 km. Particle size information derived from balloon-borne optical counters showed the presence of aerosols with a size radius >0.3µm and their subsequent sedimentation. In addition, ion chromatographic analysis of samples collected within the plume using a light-weight aerosol sampler revealed the presence of ammonia (0.3 ng/m3), sulfate (0.4 ng/m3), nitrate (1 ng/m3), and nitrite (1 ng/m3) in addition to Potassium (0.14 ng/m3), magnesium (0.12 ng/m3), and calcium (0.2 ng/m3). One of the striking findings of our measurements was the existence of traces of Dimethylamine (DMA) in our flights alongside the above-mentioned ionic components. DMA is known to enhance new particle formation upon reacting with H2SO4 and could have played an important role in the volcanic plume microphysical evolution. Although satellite data have revealed the presence of SO2 it is still uncertain if the SO2 only evolved from the Hunga-Tonga itself or as a consequence of a marine eruption that could have emitted Dimethylsulfuroxide (DMSO) into the stratosphere resulting in sulfate production. |
