Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 497766
Title The effect of stratospheric sulfur from Mount Pinatubo on tropospheric oxidizing capacity and methane
Author(s) Bândə, Narcisa; Krol, Maarten; Noije, Twan Van; Weele, Michiel Van; Williams, Jason E.; Sager, Philippe Le; Niemeier, Ulrike; Thomason, Larry; Röckmann, Thomas
Source Journal of Geophysical Research: Atmospheres 120 (2015)3. - ISSN 2169-897X - p. 1202 - 1220.
DOI https://doi.org/10.1002/2014JD022137
Department(s) Meteorology and Air Quality
WIMEK
Publication type Refereed Article in a scientific journal
Publication year 2015
Keyword(s) methane - OH - oxidizing capacity - Pinatubo - UV radiation - volcanic eruption
Abstract

The eruption of Mount Pinatubo in 1991 injected a large amount of SO2 into the stratosphere, which formed sulfate aerosols. Increased scattering and absorption of UV radiation by the enhanced stratospheric SO2 and aerosols decreased the amount of UV radiation reaching the troposphere, causing changes in tropospheric photochemistry. These changes affected the oxidizing capacity of the atmosphere and the removal rate of CH4 in the years following the eruption. We use the three-dimensional chemistry transport model TM5 coupled to the aerosol microphysics module M7 to simulate the evolution of SO2 and sulfate aerosols from the Pinatubo eruption. Their effect on tropospheric photolysis frequencies and concentrations of OH and CH4 is quantified for the first time. We find that UV attenuation by stratospheric sulfur decreased the photolysis frequencies of both ozone and NO2 by about 2% globally, decreasing global OH concentrations by a similar amount in the first 2 years after the eruption. SO2 absorption mainly affects OH primary production by ozone photolysis, while aerosol scattering also alters OH recycling. The effect of stratospheric sulfur on global OH and CH4 is dominated by the effect of aerosol extinction, while SO2 absorption contributes by 12.5% to the overall effect in the first year after the eruption. The reduction in OH concentrations causes an increase in the CH4 growth rate of 4 and 2 ppb/yr in the first and second years after the eruption, respectively, contributing 11 Tg to the 27 Tg observed CH4 burden change in late 1991 and early 1992. Key Points We modeled the effect of Pinatubo sulfur on tropospheric photochemistry SO2 absorption and aerosol extinction reduce tropospheric UV levels The tropospheric OH sink of CH4 decreased by 17.8 Tg during June 1991-June 1993

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