We analyzed the stratospheric aerosol plume from the 2022 Hunga eruption using satellite lidar data. We implemented a method to retrieve some aerosol properties, as standard products failed in this case. We found very high optical depth values in the days following the eruption, which decreased rapidly but remained elevated for months. Our results are broadly validated, though some satellite products underestimate the values due, in part, to the unusual aerosol size distribution in the plume.

Winds in the Equatorial region remain difficult to model. We take advantage of long-duration balloon campaigns from 2019 and 2021 to assess errors in winds between 18 and 20 km in a weather forecast model. Large errors persist: one third of the time, the error is larger than 3.5 m per second. This has implications for research studies that calculate air mass trajectories in this transition region between the troposphere and the stratosphere.

Gravity waves are small-scale processes that drive the circulation in the middle and upper atmosphere. In this work, we assess 3 new high-resolution models against satellite data. Generally, models capture the spatial patterns and represent stratospheric northern hemisphere mountain generated waves well. However, they still underestimate amplitudes globally and struggle with the representation of southern hemispheric convective waves.

During the first two Strateole 2 campaigns, instruments were flown under super-pressure balloons at between 18 and 20 km altitude for several weeks at the Equator and performed in situ measurements of water vapour. This article describes the methodology used to quantify the modulation of water vapour by atmospheric waves and deep convective cases. This methodology allows us to bring to light the influence of atmospheric waves and extreme deep convection on the observed water vapour anomalies.

The Hunga Tonga–Hunga Ha’apai volcano erupted on 15 January 2022, producing the largest stratospheric aerosol perturbation of the last 30 years. Stratospheric volcanic aerosols usually produce a transient climate cooling; these impacts depend on volcanic aerosol composition/size, due to size-dependent interactions with solar/terrestrial radiation. We demonstrate that the Hunga Tonga–Hunga Ha’apai stratospheric aerosols have a larger cooling potential per unit mass than the past climate-relevant El Chichón (1984) and Pinatubo (1991) eruptions.