ACCURACY OF OZONESONDE MEASUREMENTS IN THE TROPOSPHERE

Measurements of atmospheric ozone at concentrations typical of the fre e troposphere have been compared for ECC sondes and a UV-absorption ph otometer, using a Bendix chemiluminescent analyser as a transfer stand ard. Comparisons were conducted in the laboratory and in the troposphe ric part of the atmosphere. It was found that the measurements agreed to within 4% provided that the background current for the ECC sonde wa s measured before exposure to ozone in the preparation procedure, and was assumed to be constant throughout the sonde flight. These results confirm those of earlier experiments and mean that the methods current ly used to correct for the background current in the troposphere need to be revised.