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Black carbon lofts wildfire smoke high into the stratosphere to form a persistent plume

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Science  09 Aug 2019:
Vol. 365, Issue 6453, pp. 587-590
DOI: 10.1126/science.aax1748

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Up in smoke

Extensive and intense wildfires in the Pacific Northwest of the United States in 2017 injected large quantities of smoke into the stratosphere. Yu et al. used satellite observations and modeling to characterize the history and chemistry of that smoke. The smoke rose to altitudes between 12 and 23 kilometers within 2 months owing to solar heating of black carbon. The smoke then remained in the stratosphere for more than 8 months. Photochemical loss of organic carbon resulted in a smoke lifetime 40% shorter than expected.

Science, this issue p. 587

Abstract

In 2017, western Canadian wildfires injected smoke into the stratosphere that was detectable by satellites for more than 8 months. The smoke plume rose from 12 to 23 kilometers within 2 months owing to solar heating of black carbon, extending the lifetime and latitudinal spread. Comparisons of model simulations to the rate of observed lofting indicate that 2% of the smoke mass was black carbon. The observed smoke lifetime in the stratosphere was 40% shorter than calculated with a standard model that does not consider photochemical loss of organic carbon. Photochemistry is represented by using an empirical ozone-organics reaction probability that matches the observed smoke decay. The observed rapid plume rise, latitudinal spread, and photochemical reactions provide new insights into potential global climate impacts from nuclear war.

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