Dependence of the surface ozone concentration on the air temperature and conditions of atmospheric circulation in Western Siberia in the warm season (May-September)

摘要

The relationship between the surface ozone concentration and the air temperature (O_3-T) is rather strong. It is more pronounced for day-to-day variations of O_3 and T for every particular month in comparison with year-to-year variations of monthly average values. The O_3-T relationship is variable from one year to another. The correlation coefficient can be both positive (achieving about 0.8) and negative. The analysis of some cases revealed that the magnitude of O_3-T relationship depends on the character of atmospheric circulation. For the analyzed situations, the O_3-T correlation was stronger at the well-developed advection processes and dynamic alternation of air masses. We have found that the increase of the surface ozone concentration and the air temperature at the measurement site for the cases of threefold and higher excess of the maximum permissible diurnal average ozone concentration (MPCda) occurs synchronously with the alternation of air masses. The analysis of the geopotential height gradient (GHGS) and the corresponding behavior of the potential temperature at the level of dynamic tropopause has demonstrated that, in general, GHGS well reflects the dynamics of air mass alternation, at least, for the most of analyzed cases of heat and cold waves. The use of the rigorous blocking criterions (GHGS>0) yielded no positive results. In addition, no one case of threefold and higher excess of MPCda of ozone was observed for the conditions of "actual" blocking with a duration of five and more days.