Long-term variations in tropospheric ozone content

Data obtained at the world acrological network in the past few decades on surface ozone and vertical ozone distribution within the troposphere are analyzed. It is shown that the observed trends of variations in surface ozone and free-troposphere ozone are different and depend strongly on the observation site and the period of time for which they are calculated. Over the time period 1973-2001, at the American tropical stations Samoa and Mauna Loa (high-altitude), the level of surface ozone concentration underwent no statistically significant changes, and the surface ozone concentrations ceased to decrease in the South Pole region and ceased to increase in the hi-h latitudes in the Alaskan region. The deviations of ozone concentration from its long-term mean values for different tropospheric altitudes correlates with temperature deviations at the same altitudes and with the tropopause height. It is concluded that, to interpret long-term variations in tropospheric ozone, these should be considered together with variations in other meteorological parameters, primarily in temperature, whose variations are more reliably recorded due to a significantly greater number of observations. The longterm (on a scale of ten years or longer) variations in tropospheric ozone manifest their relations in the tropopause-height increase observed at the world aerological network.