4. Summary

The annual cycle of total ozone is driven by that of the tropospheric and lower-stratospheric ozone taking maxima in Northern summer and minima in Northern winter almost simultaneously in the whole altitude range. The Tropopause effect is not a major factor that drives such variations, although some contribution is confirmed. The interannual variations of temperature and height of the cold point tropopause is not directly related to the ENSO phenomenon, and the east-west contrast in these quantities are not evident between San Cristobal and Singapore. Extremely low values of the upper tropospheric ozone have not been encountered even under the El Nino condition in rainy season. The out-of-phase relationship between the ozone and relative humidity is frequently observed in September indicating the long range transport of ozone and its precursors from the continental region. In some cases, low values of ozone concentration is observed in the marine boundary layer whose trajectories are constrained over the west coast of South America. The activity of vertically propagating waves is high in the eastern tropical Pacific, and such waves may play an important role in the water vapor transport between the troposphere and stratosphere thus acting as a "stratospheric draining pump" that maintains the dry condition of the stratosphere.


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Abstract || 1. Introduction || 2. Characteristic Ozone Profiles || 3. Contribution of Waves || Acknowledgments || References