The Evolution and Dynamics of Hunga Tonga-Hunga Ha'apai Stratospheric Plume over One Year and Half after the Eruption - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

The Evolution and Dynamics of Hunga Tonga-Hunga Ha'apai Stratospheric Plume over One Year and Half after the Eruption

Résumé

This study is based on the combination of data from CALIOP, OMPS-LP, IASI, MLS, SAGE-III, AHI/HIMAWARI, ATLID/AEOLUS, COSMIC2 and balloon LOAC measurements. The main stratospheric plume of the Tonga eruption, very rich in water vapour and from which ash particles have been washed out within the first hours after the eruption, underwent a fast conversion of SO2 to sulfates within the first 15 days. IASI observations show that SO2 has returned to background levels by the beginning of February 2022. The large amount of water vapour in the plume induced a radiative cooling and a descent of 4 to 6 kilometers during the first 3 weeks. Compact patches of aerosols survive until March 2022 due to the water vapour cooling and the formation of anticyclonic meso-scale structures. During the following months, sedimenting aerosols and water vapour separated vertically. The water vapour ascended within the Brewer Dobson circulation (BDC), first slowly then very rapidly (up to 150 m/day) during the winter 2022-2023 due to the successive phases of the QBO. The resulting pattern in the tropics is a strong perturbation of the tape recorder amplitude. The aerosol plume dispersed in latitude and altitude but penetrated hardly beyond 30°N in the northern hemisphere until April 2023. The vortex jet has been a barrier in the southern hemisphere until fall 2022. Due to the BDC, the aerosol sedimented in the extratropical southern hemisphere but stayed at a fairly constant level around 22 km in the tropical domain. The result is a sloping distribution descending to about 15 km at southern hemispheric high latitudes. The effective radius of the aerosols determined from SAGE III and fall rates, and in agreement with LOAC in situ observations, has been very stable in the 0.35-0.40 µm range even if a decreasing trend appears during winter 2022-2023. The width of the distribution is relatively narrow, basically twice smaller than that of the background and this is also persistent in time. The total mass of stratospheric sulphate aerosols as measured from SAGE III is about 0.66 Tg of H2SO4 corresponding to 0.44 Tg of SO2 at the source, even if considerable redistribution occurred in latitude and altitude.
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insu-04652820 , version 1 (18-07-2024)

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Bernard Legras, Clair Duchamp, Pasquale Sellitto, Elisa Carboni, Richard Siddans, et al.. The Evolution and Dynamics of Hunga Tonga-Hunga Ha'apai Stratospheric Plume over One Year and Half after the Eruption. AGU Fall Meeting 2023, 0000, à renseigner, Unknown Region. ⟨insu-04652820⟩
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