A time series for carbonyl sulfide in the northern hemisphere

Abstract

The variation of OCS in the northern hemisphere for the period 1977-1991 was investigated by grouping 'all measurements made by our research group for that period. The data set contained 1066 measurements made in the northern hemisphere over a longitude range of 52 E to 155 W and a latitude range of l0 N to 85 N. About 50% of the measurements were made from aircraft. The overall data set had a meau of 512 parts per trillion by volume (pptv) and a standard deviation of 119 pptv. The data obtained from aircraft had a mean of 514 pptv aud a standard deviation of 64 pptv. A study of the time series constructed from the data set and several subsets indicate that the change in global OCS with time is between -1.5 and 1.5 parts per trillion per year at the 95% confidence level. The data had no seasonal dependence within the precision of the data set.

Characteristics and anthropogenic sources of carbonyl sulfide in Beijing

“…Compared to other studies, the annual average mixing ratio of 639 ± 332 pptv (n = 555) in this study is much higher than the background value of 512 ± 119 pptv in the free troposphere of the Northern Hemisphere (Torres et al, 1980;Bandy et al, 1992) and comparable to the value of 646 ± 48 pptv observed in Hong Kong (Guo et al, 2010), but much lower than that of 1021 ± 221 pptv measured in the inner Pearl River Delta (PRD) (Guo et al, 2010).…”

“…For example, the average COS mixing ratio of 507 ± 96 pptv for 61 samples measured in Beijing under strongly windy conditions (wind speed > 6 m/sec) was consistent with the COS background level of 512 ± 119 pptv in the Northern Hemisphere (Torres et al, 1980;Bandy et al, 1992). Based on this fact, more convincing evidence for the strong vegetation uptake in summer and extra ground emissions in winter could be found in the diurnal variations of COS under typical windy days.…”

“…The frequency (<1%) of COS mixing ratios higher than 2000 pptv, which were occasionally measured under stagnant air conditions (haze days), was much lower than the 13% frequency observed in 2001. The significant difference of COS mixing ratios between the two measurements revealed that COS sources around Beijing had been greatly reduced since 2001, for example most boilers fueled by coal have been replaced by boilers fueled by relatively clean oil and natural gas in recent years, and the numbers of domestic coal stoves in the urban fringe of Beijing have been greatly reduced with the fast development of urbanization.Compared to other studies, the annual average mixing ratio of 639 ± 332 pptv (n = 555) in this study is much higher than the background value of 512 ± 119 pptv in the free troposphere of the Northern Hemisphere (Torres et al, 1980;Bandy et al, 1992) and comparable to the value of 646 ± 48 pptv observed in Hong Kong (Guo et al, 2010), but much lower than that of 1021 ± 221 pptv measured in the inner Pearl River Delta (PRD) (Guo et al, 2010). …”

Dark production: A significant source of oceanic COS

“…Its atmospheric burden is an estimated 5.2 Tg [Chin and Davis, 1995], and its average global mixing ratio (•510 ppt) shows relatively little spatial and temporal variability [Bandy et al, 1992]. COS is chemically stable, and its atmospheric residence time is estimated to be •6 years [Ulshbfer and Andteac, 1998].…”

Photochemical production of carbonyl sulfide in North Sea water: A process study

“…Its oxidation by OH radicals is relatively slow, resulting in a tropospheric lifetime with respect to OH oxidation of more than 9 yr (Hewitt and Davison 1988). The tropospheric residence time of COS estimated from its global atmospheric burden (Khalil and Rasmussen 1984) and source strength (Chin and Davis 1993) is -4 yr. Consequently, COS is rather uniformly distributed in the troposphere with a mean mixing ratio of -500 pptv (Bandy et al 1992). Its inertness against photoxidation allows COS to be transported to the stratosphere, where it is photodissociated and oxidized to form sulfuric acid aerosol.…”