Measurements of free tropospheric ozone: An aircraft survey from 44° north to 46° south latitude

Ozone data were obtained in the free troposphere at altitudes of 5 to 7.5 km and at latitudes from 44°N to 46°S during a 3‐week period from October 19 to November 4, 1982. Flight trajectories included the continental U.S., Central America, and the western coast of South America. Maximum observed ozone was 110 ppb at about 41°S latitude and at an altitude of 7.3 km (msl). Analysis of the data as a function of latitude showed a region of elevated ozone in the southern latitudes extending from about 2° to 30° in which latitudinal ozone averages (2° bands) peaked at about 80 ppb. Ozone concentrations, measured at northern latitudes, were lower, averaging about 35 ppb. A discussion of the data, including comparison with other ozone data sets, is presented.