We measured the concentration of carbonyl sulfide (OCS) in the marine atmospheric boundary layer and in the surface layer of the equatorial and northern Pacific Ocean on two oceanographic cruises during May and June of 1982 and during March–May of 1983. Our measurements of the mean concentration of atmospheric OCS are 502 ± 21 parts per trillion (ppt) on the 1982 cruise and 511 ± 19 ppt on the 1983 cruise. We found surface water OCS concentrations to range upward from 0.3 STP nL L−1 to a few cases over 3.0 STP nL L−1. We estimate the global mean supersaturation ratio of OCS in seawater to range from 1.5 to 3.0, indicating a global source of OCS from the ocean of 0.2 to 0.4 Tg yr−1. We have made laboratory measurements of the dimensionless Henry's law coefficient of solubility H, the concentration of OCS in air divided by its concentration in 34.90 per mil salinity seawater. We found ln H = 12.722 ± 0.082 − (3,496 ± 24)/T, with no evidence for nonlinearities in the solubility at ambient atmospheric concentrations of OCS.

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We present summaries of 703 previously unanalyzed ozonesonde launches at six stations distributed along a meridional band near 75øW between 9 ø and 53øN. Altitude and seasonal variations are examined to assist understanding the patterns and relative roles of injection, transport, loss, and synthesis of ozone in the middle troposphere. By comparison with other North American stations we conclude that a longitudinal gradient of 10-20% is likely, increasing eastward. The data are generally consistent with conventional understanding of tropospheric ozone in terms of increased injection from the stratosphere during spring at high latitudes, southward transport with molecular lifetimes of several months, and a principal sink at the ground, but details of the altitude and seasonal behavior can be interpreted ambiguously as evidence either for shorter-scale transport or for ozone synthesis within the troposphere. LONGITUDINAL VARIATIONSSince zonal circulations and mixing along the lines of latitude are, in general, more rapid and efficient than meridional circulations and mixing along the longitude circles, it is plausible to expect an approximate zonal symmetry for tropospheric ozone, providing that its lifetime in the troposphere is longer than or comparable to the zonal circulation time of about Paper number 7C0490. 5969

Ozone in the lower troposphere has traditionally been attributed to two different sources, injection from the stratosphere and local or regional photochemical synthesis. Recently, Chameides and Walker [1973, 1976] proposed that photochemical synthesis of ozone (via a methane oxidation chemistry) is significant in areas remote from obvious pollution. They characterize as their ‘basic argument that photochemical sources of ozone in the troposphere are larger than the source provided by transport from the stratosphere’ [Chameides and Walker, 1974]. This photochemical hypothesis appears welcome amid several reports of repeated but intermittent high concentrations of ozone at surface measuring stations in supposedly unpolluted areas [A ttmannspacher and Hartmannsgruber, 1973; Wallis et al., 1975] (also, data of L. A. Ripperton and J. J. B. Worth as summarized by Corn et al. [1975]).