An intercomparison of SAGE and SBUV ozone observations for March and April 1979

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Abstract
Thirty‐eight latitudinal cross sections of stratospheric ozone observed by the SAGE and SBUV satellite instruments on the same days in March and April 1979 and at approximately the same latitude are compared. Differences in the zonal‐mean mixing ratios are found. At pressures less than 5 mbar, SAGE gives approximately 20% larger mixing ratios at tropical latitudes (after a correction has been applied for the expected diurnal variation of ozone.) At 50°–70° latitude at 10 mbar, the SBUV retrievals appear to underestimate ozone by approximately 15%. Mixing ratio differences are also noted in the tropics at 30 mbar. Longitudinal variations with a vertical scale exceeding 8 km are analyzed. The uncorrelated portions of the SAGE variances are approximately consistent with the SAGE noise model and resulting ozone profile error bars. Between 2 and 10 mbar, the random noise in an individual wave component (having this vertical scale) is expected to be less than 2% everywhere in both experiments except for 1% at tropical latitudes in the SBUV experiment. Based upon the correlated variances, the amplitudes of the inferred longitudinal ozone variations are found to be the same on the average at mid‐latitudes between 1 and 10 mbar. However, the relative amplitudes also are found to be dependent on the atmospheric situation. Systematic differences in the amplitudes at 0.4 and 30 mbar are discussed. Wave detectability by both sensors at 58°S in early April is illustrated and compared against TIROS‐N temperature observations for that period.