On the possibility of soot (black carbon) formation at powerful volcanic eruptions
S.A. Beresnev, E.D. Ganieva, M.S. Vasileva, L.B. Kochneva
Institute of Natural Sciences, Ural Federal University named after the first President of Russia B.N. Yeltsin, Ekaterinburg, Russia
Keywords: black carbon, magmatic volcano, Plinian eruption, methane, stratosphere, volcanic ash
Abstract
Soot aerosol particles (black carbon) significantly contribute to atmospheric heating by effectively absorbing radiation across a wide range of wavelengths and, along with greenhouse gases, play an important role in climate change. The hypothesis of volcanogenic soot in the stratosphere (a possibility of formation of black carbon nanoparticles during Plinian volcanic eruptions and their casting to high altitudes) is critically analyzed. Features of thermal decomposition of methane and formation of reduced carbon in a two-phase gas-ash volcanic column are discussed. Known data on the detection of carbonaceous particles in the atmosphere, their properties, and possible, but not yet confirmed, connection with powerful volcanic eruptions are evaluated. The discovery of different reduced carbon forms in the ashes of modern volcanic eruptions in Kamchatka (the phenomenon of volcanic carbon paragenesis) is commented on. Energy competition between two ways of formation of reduced carbon in the forms of soot nanoparticles and carbon products strongly mechanically bonded to pyroclastic material is discussed. The results can be useful for atmospheric aerosol physics and climatology in analyzing the main sources of black carbon in the atmosphere.
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