Enhanced upper tropical tropospheric COS: impact on the stratospheric aerosol layer.

Notholt, J; Kuang, Z; Rinsland, C P; Toon, G C; Rex, M; Jones, N; Albrecht, T; Deckelmann, H et al. · Science · 2003

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Abstract

Carbonyl sulfide (COS) is considered to be a major source of the stratospheric sulfate aerosol during periods of volcanic quiescence. We measured COS at the tropical tropopause and find mixing ratios to be 20 to 50% larger than are assumed in models. The enhanced COS levels are correlated with high concentrations of biomass-burning pollutants like carbon monoxide (CO) and hydrogen cyanide (HCN). The analysis of backward trajectories and global maps of fire statistics suggest that biomass-burning emissions transported upward by deep convection are the source of the enhanced COS in the upper tropical troposphere.