Ozone and carbon monoxide over the North Atlantic during a boreal summer

Abstract

Ozone mixing ratios observed on a cruise from the east coast of North America to Bermuda, to Iceland, to the Azores and terminating in Barbados in a boreal summer exhibit wide variability. Increases above a North Atlantic background of 10–20 ppbv appear to be associated with transport from terrestrial systems. In the central gyre of the North Atlantic and in the tropical North Atlantic, ozone mixing ratios below 10 ppbv are commonly observed when the air being sampled does not have a recent (10 days) history of terrestrial input. Carbon monoxide mixing ratios within the boundary layer vary latitudinally from an average of 124 ppbv in the westerlies to 88 ppbv in the tropical North Atlantic. Variability in the distribution of CO appears to be dominated by transport from terrestrial source regions.