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Figure 3. Latitudinal structure of the solar cycle regression coefficient calculated from TOMS zonal (5°) total ozone data for the period 1979-1992. Vertical dashed lines indicate 1 standard error (SE) limits. From Reinsel et al. (2002).

Figure 3. Latitudinal structure of the solar cycle regression coefficient calculated from TOMS zonal (5°) total ozone data for the period 1979-1992. Vertical dashed lines indicate 1 standard error (SE) limits. From Reinsel et al. (2002).

of 260 to 330 DU depending on latitude, this corresponds to an overall amplitude of the total ozone solar cycle of 1-2%.

Three mechanisms have been proposed to explain the observed features. The first mechanism invokes photochemical control of total ozone, which would however imply a maximum response amplitude at the equator and could only account for a limited share of the observed total ozone changes (Hood, 2004). The second hypothesis involves changes in mean lower stratospheric dynamics between solar minimum and solar maximum. This hypothesis is supported by model results, and by isolated observations of a phase-shift between ozone and solar variations, with ozone appearing to lead the solar flux changes by 2 seasons (Angell, 1989). Finally, observational and numerical evidence was found recently (Sinnhuber et al., 2005; Langematz et al., 2005; Rozanov et al., 2005) for the influence of solar cycle-related energetic electrons precipitation effects on stratospheric ozone, that could induce enhanced total ozone values at high latitudes during solar maximum.

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