Ozone in the upper troposphere from gasp measurements

Abstract

Several aspects of tropospheric ozone variations are examined by using ozone measurements made from commercial airliners (Gasp data). The east‐west variations of ozone have a predominant wavelength near 2400 km, by visual inspection of the autocorrelation function, while temperature and wind have predominant wavelengths near 3300 km. The different wavelengths may be due to a sampling bias. Distance‐lagged correlation functions of ozone with temperature and wind show a definite periodicity with wavelengths near 2400 km. The low correlation of ozone with meridional wind speed at lag zero makes it necessary to have many pairs of data to estimate even the sign of the meridional ozone flux with confidence. Tropical tropospheric ozone values above 100 parts per billion by volume (ppbv) appear to be associated with meridional transport from middle latitudes, and in some cases, relatively large tropical ozone values are coincident with clouds. A diurnal variation with amplitude near 2.0 ppbv is found with phase (time of maximum value) near 0800 LT at 32°–64°N but with phase near 1700 LT at 16°–32°N.