Erlangen 2026 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 4: Near-Earth Space

EP 4.1: Invited Talk

Wednesday, March 18, 2026, 11:00–11:30, KH 01.019

Assessing the immediate dynamical and long-term radiative effects of the Hunga Tonga Hunga Ha'apai volcanic eruption using state-of-art active and passive ground-based remote sensing — •Gunter Stober — University of Bern, Institute of Applied Physics, Bern, Switzerland — Oeschger Center for Climate Change Research, Bern, Switzerland

The Hunga Tonga Hunga Ha'apai (HTHH) volcanic eruption on 15th January 2022 launched atmospheric gravity waves (GW) traveling around the entire globe, reaching altitudes up to the mesosphere/ lower thermosphere (MLT) and even beyond that height. These GW had unprecedentedly high phase speeds of 170-240 m/s and reached amplitudes of 40- 50 m/s in the zonal and meridional wind components. Global available meteor radar observations of MLT winds together with multistatic meteor radar networks and high-resolution gravity wave modeling with the High Altitude Mechanistic Circulation Model (HIAMCM) reveal the global propagation of the volcanic GW and their global propagation for more than 24 hours.

However, the larger impact of the HTHH eruption is caused by the released water vapor. The volcanic plume injected about 13 Tg of water vapor into the stratosphere and mesosphere. Due to residual circulation, this water vapor is now distributed around the globe and observed by both ground-based and space-borne sensors. Here, we present observations of ground-based and balloon-borne sensors to measure the excess water vapor due to HTHH in the middle atmosphere.

Keywords: Hunga Tonga Hunga Ha'apai; Gravity waves; vertical coupling; radiative transfer; water vapor