Impact of ashes from the 2022 Tonga volcanic eruption on satellite ocean color signatures

Frontiers in Marine Science

Marine Science

Andra Whiteside¹  Cécile Dupouy²  Philipson Bani³  Awnesh Singh⁴  Robert Frouin⁵  Jing Tan⁵ 

[1] Aix Marseille Université, Université de Toulon, Centre National de la Recherche Scientifique (CNRS)/Ĺinstitut national des sciences de ĺUnivers (INSU), Institut de Recherche pour le Développement (IRD), Mediterranean Institute of Oceanography (MIO), Marseille, France;Pacific Centre for Environment and Sustainable Development (PaCE-SD), University of the South Pacific, Suva, Fiji;Aix Marseille Université, Université de Toulon, Centre National de la Recherche Scientifique (CNRS)/Ĺinstitut national des sciences de ĺUnivers (INSU), Institut de Recherche pour le Développement (IRD), Mediterranean Institute of Oceanography (MIO), Marseille, France;Pacific Centre for Environment and Sustainable Development (PaCE-SD), University of the South Pacific, Suva, Fiji;Institut de Recherche pour le Développement (IRD), Nouméa, New Caledonia;Institut de Recherche pour le Développement (IRD), Nouméa, New Caledonia;Laboratoire Magmas Et Volcans, Université Clermont–Auvergne–CNRS–IRD, L'Observatoire de Physique du Globe de Clermont-Fd (OPGC), Aubière, France;Pacific Centre for Environment and Sustainable Development (PaCE-SD), University of the South Pacific, Suva, Fiji;Scripps Institution of Oceanography, University of California, San Diego, CA, United States;

关键词: chlorophyll-a (Chl-a);    HTHH;    light attenuation;    particle backscattering;    ocean currents;    volcanic ash;    remote sensing;   

DOI  :  10.3389/fmars.2022.1028022

 received in 2022-08-25, accepted in 2022-11-25,  发布年份 2023

来源: Frontiers

【 摘 要 】

A powerful eruption within the Hunga Tonga-Hunga Ha’apai (HTHH) volcano (20.64°S, 175.19°W) in the Kingdom of Tonga, occurred on 15 January 2022. The volcanic blast was enormous, leading many scientists to investigate the full impact and magnitude of this event via satellite observations. In this study, we describe a new ocean color signature from a discolored water patch created by the HTHH eruption using NASA and CMEMS products of satellite-derived biological and optical properties. Elevated surface chlorophyll-a concentration (Chl-a) between 0.15 to 2.7 mg.m-3 was not associated with phytoplankton growth, but to basalt-andesitic ash material expelled by the volcano and into the ocean, which resulted in erroneous Chl-a estimates. Distribution of the patch over time was aligned with CMEMS ocean currents for 19 days. The gradual decrease of light attenuation or diffuse attenuation coefficient for downward irradiance at 490 nm, Kd(490), was interpreted as due to the sinking of ash particles with time. It is suggested that due to high porosity of 30-40%, a density close to that of seawater, ash particles stay suspended in the water column for more than 10 days with sustained high values of satellite-derived Chl-a, Kd(490), and particulate backscattering coefficient at 443 nm. The high attenuation of light due to ash, reducing the penetration depth to less than 10 meters during the first period after the eruption may have had implications on ecological processes and biogeochemical cycles in Tongan waters.

【 授权许可】

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Copyright © 2023 Whiteside, Dupouy, Singh, Bani, Tan and Frouin