A TIME-SERIES FOR CARBONYL SULFIDE IN THE NORTHERN-HEMISPHERE

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 10 N to 85 N. About 50% of the measurements were made from aircraft. The overall data set had a mean 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 and 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.