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Abstract Carbonyl sulfide (COS) was measured in firn air collected during seven different field campaigns carried out at four different sites in Greenland and Antarctica between 2001 and 2015. A Bayesian probabilistic statistical model is used to conduct multisite inversions and to reconstruct separate atmospheric histories for Greenland and Antarctica. The firn air inversions cover most of the 20th century over Greenland and extend back to the 19th century over Antarctica. The derived atmospheric histories are consistent with independent surface air time series data from the corresponding sites and the Antarctic ice core COS records during periods of overlap. Atmospheric COS levels began to increase over preindustrial levels starting in the 19th century, and the increase continued for much of the 20th century. Atmospheric COS peaked at higher than present‐day levels around 1975 CE over Greenland and around 1987 CE over Antarctica. An atmosphere/surface ocean box model is used to investigate the possible causes of observed variability. The results suggest that changes in the magnitude and location of anthropogenic sources have had a strong influence on the observed atmospheric COS variability. 

Measurements were conducted to determine the carbonyl sulfide levels in ancient air preserved in the Greenland ice sheet using samples from the GISP2D and GISP2B ice cores from Summit, Greenland. The GISP2D is a fluid-drilled core and the GISP2B is a dry-drilled core. This data set includes four CSV files. Most of the measurements are from the GISP2D ice core and 3 out of the 4 data files associated with this submission include data from the GISP2D. Both dry and wet extraction methods were used to extract the ice core air. All dry extraction-based GISP2D data are presented in one file. The wet extraction-based data are split between 3 data files: 1) GISP2B data, 2) shallow GISP2D data, 3) deep GISP2D data. The shallow and deep wet extraction-based GISP2D data are presented in 2 separate files despite including some overlapping depths because the measurements were conducted over different time periods. All data are depth-coded and presented "as measured" with associated 1 sigma uncertainties after having gone through a preliminary quality control and having been finalized in terms of calibration. Note that the wet extraction-based measurements require a solubility correction before they can be compared with the dry extraction-based measurements from the same depths. 

Abstract. Carbonyl sulfide (COS) is the most abundant sulfur gas in the atmosphere with links to terrestrial and oceanic productivity. We measured COS in ice core air from an intermediate-depth ice core from the South Pole using both dry and wet extraction methods, recovering a 52 500-year record. We find evidence for COS production in the firn, altering the atmospheric signal preserved in the ice core. Mean sea salt aerosol concentrations from the same depth are a good proxy for the COS production, which disproportionately impacts the measurements from glacial period ice with high sea salt aerosol concentrations. The COS measurements are corrected using sea salt sodium (ssNa) as a proxy for the excess COS resulting from the production. The ssNa-corrected COS record displays substantially less COS in the glacial period atmosphere than the Holocene and a 2 to 4-fold COS rise during the deglaciation synchronous with the associated climate signal. The deglacial COS rise was primarily source driven. Oceanic emissions in the form of COS, carbon disulfide (CS2), and dimethylsulfide (DMS) are collectively the largest natural source of atmospheric COS. A large increase in ocean COS emissions during the deglaciation suggests enhancements in emissions of ocean sulfur gases via processes that involve ocean productivity, although we cannot quantify individual contributions from each gas.