火災雲中のブラックカーボンによる太陽光吸収を定量化(WashU researchers quantify solar absorption by black carbon in fire clouds)

2024-07-25 ワシントン大学セントルイス校

＜関連情報＞

• https://source.wustl.edu/2024/07/washu-researchers-quantify-solar-absorption-by-black-carbon-in-fire-clouds/
• https://www.nature.com/articles/s41467-024-50070-0

火山雲中のブラックカーボンによる光吸収の促進 Light absorption enhancement of black carbon in a pyrocumulonimbus cloud

Payton Beeler,Joshin Kumar,Joshua P. Schwarz,Kouji Adachi,Laura Fierce,Anne E. Perring,J. M. Katich & Rajan K. Chakrabarty
Nature Communications  Published:25 July 2024
DOI:https://doi.org/10.1038/s41467-024-50070-0

Abstract

Pyrocumulonimbus (pyroCb) firestorm systems have been shown to inject significant amounts of black carbon (BC) to the stratosphere with a residence time of several months. Injected BC warms the local stratospheric air, consequently perturbing transport and hence spatial distributions of ozone and water vapor. A distinguishing feature of BC-containing particles residing within pyroCb smoke is their thick surface coatings made of condensed organic matter. When coated with non-refractory materials, BC’s absorption is enhanced, yet the absorption enhancement factor (E_abs) for pyroCb BC is not well constrained. Here, we perform particle-scale measurements of BC mass, morphology, and coating thickness from inside a pyroCb cloud and quantify E_abs using an established particle-resolved BC optics model. We find that the population-averaged E_abs for BC asymptotes to 2.0 with increasing coating thickness. This value denotes the upper limit of E_abs for thickly coated BC in the atmosphere. Our results provide observationally constrained parameterizations of BC absorption for improved radiative transfer calculations of pyroCb events.