Sunset–sunrise difference in solar occultation ozone measurements (SAGE II, HALOE, and ACE–FTS) and its relationship to tidal vertical winds

摘要

This paper contains a comprehensive investigation of the sunset–sunrisedifference (SSD, i.e., the sunset-minus-sunrise value) of the ozone mixingratio in the latitude range of 10° S–10° N. SSD valueswere determined from solar occultation measurements based on data obtainedfrom the Stratospheric Aerosol and Gas Experiment (SAGE) II, the HalogenOccultation Experiment (HALOE), and the Atmospheric Chemistry Experiment–Fourier transform spectrometer (ACE–FTS). The SSD was negative at altitudesof 20–30 km (−0.1 ppmv at 25 km) and positive at 30–50 km (+0.2 ppmv at40–45 km) for HALOE and ACE–FTS data. SAGE II data also showed aqualitatively similar result, although the SSD in the upper stratosphere was2 times larger than those derived from the other data sets. On the basis ofan analysis of data from the Superconducting Submillimeter-Wave Limb-EmissionSounder (SMILES) and a nudged chemical transport model (the specifieddynamics version of the Whole Atmosphere Community Climate Model:SD–WACCM), we conclude that the SSD can be explained by diurnal variationsin the ozone concentration, particularly those caused by vertical transportby the atmospheric tidal winds. All data sets showed significant seasonalvariations in the SSD; the SSD in the upper stratosphere is greatest fromDecember through February, while that in the lower stratosphere reaches amaximum twice: during the periods March–April and September–October. Basedon an analysis of SD–WACCM results, we found that these seasonal variationsfollow those associated with the tidal vertical winds.