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Stratospheric water vapor from the Hunga Tonga - Hunga Ha'apai volcanic eruption deduced from COSMIC-2 radio occultation
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  • William J. Randel,
  • Benjamin Johnston,
  • John J. Braun,
  • Sergey Sokolovskiy,
  • Holger Voemel,
  • Aurélien Podglajen,
  • Bernard Legras
William J. Randel
National Center for Atmospheric Research (UCAR)

Corresponding Author:randel@ucar.edu

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Benjamin Johnston
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John J. Braun
Univ Corp for Atmospheric Res. (UCAR)
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Sergey Sokolovskiy
University Corporation for Atmospheric Research (UCAR)
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Holger Voemel
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Aurélien Podglajen
Laboratoire de météorologie dynamique, Ecole Polytechnique
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Bernard Legras
Ecole Normale Superieure
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The eruption of the Hunga Tonga – Hunga Ha’apai (HTHH) volcano on January 15, 2022 injected large amounts of water vapor directly into the stratosphere. While normal background levels of stratospheric water vapor are not detectable in radio occultation (RO) measurements, effects of the HTHH eruption are clearly observed as anomalous refractivity profiles from COSMIC-2, suggesting the possibility of detecting the HTHH water vapor signal. To separate temperature vs. water vapor effects on refractivity, we use co-located temperature observations from the Microwave Limb Sounder (MLS) to constrain a simplified water vapor retrieval. Our results show enhancements of water vapor up to ~1500-2300 ppmv in the stratosphere (~29-33 km) in the days following the HTHH eruption, with propagating patterns that follow the dispersing volcanic plume. The stratospheric water vapor profiles derived from RO are in reasonable agreement with limited radiosonde observations over Australia.