The integrated assessment of the influence of air mass transport directions on the average long-term seasonal variations of concentrations of minor gas components (MGC: ozone, CO, NO 2 ) of the atmosphere is carried out according to the data of a number of European stations. Distributions of nitrogen dioxide and carbon monoxide concentrations according to transport directions are similar to each other and differ considerably from the distribution of ozone concentrations. It is demonstrated that the relationships of levels of spring and summer ozone concentrations maxima differ considerably at all examined stations in different regions of Europe depending on different transport directions: the summer maximum is stronger pronounced according to the data for the southern and eastern directions than according to the data for the northern and western directions. The change of air transport directions may account for from 10% (Moscow region) to 30-40% (the northwest of continental Europe and Ireland) variations of MGC concentration. The obtained results point out the perspective of their use in statistical models of the forecast of MGC concentrations.In view of the urgent problem of investigation of the air quality, the important problem is the revelation of variability of concentration of the surface ozone and a number of its predecessors: nitrogen oxide (NO x = = NO + NO 2 ) and carbon monoxide (CO). The ozone predecessors in the boundary layer of atmosphere are mainly of the anthropogenic origin and are the primary pollutants, and the ozone is the secondary one (i.e., its high concentrations are generated during the photochemical reactions with the participation of primary pollutants and volatile organic compounds), especially in populous regions. The natural sources also contribute to the generation of observed concentrations of CO (biomass combustion) and NO x (lightnings), however, this contribution is considerably smaller than the anthropogenic activity. Variations in concentrations of the above atmospheric components are determined to a considerable degree by meteorological factors, first of all, by the temperature regime and processes, influencing the inflow and scattering of admixtures, among which the important role belongs to the processes of air mass transport. Generally, the transport characteristics are used to account for certain peculiarities of ozone concentration variations [6,[8][9][10][11]13] but they can be used in models for ozone concentration forecasting [4,5,7]. The reasons causing high ozone concentrations, in particular, those associated with the emission and transport of atmospheric pollutants, are actively studied in Europe in view of frequently repeated episodes of reaching the dangerous concentrations and observed global increase in the ozone concentration [8,10,11]. In this work, the integrated assessment of the influence of air mass transport directions on average long-term seasonal variations of concentrations of minor gas components (MGC: ozone, CO, NO 2 ) of atmosphere for the purpo...

Characteristics of periodic variability of surface ozone concentration at 98 western and central European stations participating in the EMEP program for at least 7 (up to 14) years are determined. Daily and hourly model concentrations of surface ozone for each station are given in an analytical form that presents a sum of a constant constituent and basic harmonics that determine ozone concentration variability throughout a year and a day. A 12-month harmonic, whose maximum is observed in the spring period (in Northern Europe it is observed 1 to 2 months earlier than in Southern Europe) dominates in the energy spectrum of seasonal variability of daily mean ozone concentration at most stations. The energy part of higher (6-and 4-month) harmonics is the largest at the stations close to the sea and ocean coasts. Higher harmonics largely influence the time of the ozone extremum formation, shifting it towards the summer, or even forming a second (summer) maximum, whose magnitude at a number of stations (in Italy, Hungary, in the south of Germany, and in some others) exceeds the spring maximum. A 24-hour harmonic dominates in the energy spectrum of daily ozone variability. The maps of a "normal" distribution of surface ozone fields and their standard deviations for different seasons and time of the day have been compiled based on the model characteristics. The "norms" derived can be used to detect anomalies in the temporal trend of the surface ozone and to validate its climate changes.

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Total ozone (TO) over Russia is on average above the annual mean global TO of about 300 DU almost throughout the year. "Normal" dynamics of TO changes over Russia in the second quarter is shown in Fig. 1 1 (colored maps of "normal" ozone distribution over the globe and in each hemisphere can be found at http://www.cao-rhms.ru/oisa/ and http://expstudies.tor.ec.gc.ca/e/ozone/). Compared with the total ozone over Russia and adjoining areas in March, its content in April decreased. Total ozone continues to decrease in May and June, and the most significant decrease is observed in Eastern Siberia. The maximum TO decrease is observed in the region of the Sea of Okhotsk coast, while the minimum occurs in the south of European Russia. As a result, the TO distribution over Russia, which in the first quarter was largely meridional, becomes almost zonal by June. The "normal" TO of 320-340 DU should settle in June over Russia within the entire zonal belt of 45°-65°N; in lower and higher latitudes, the TO content should be somewhat lower.Mean TO values in the second quarter of 2008 over the area under control were, mainly, lower than the long-term means for 1974-1984 (Fig. 2a). Abnormally low quarterly mean TO values were recorded over Kazakhstan, the south of Siberia, Yakutia, Far East, Kamchatka, and the Chukchi Peninsula (Alma-Ata, Karaganda, Semipalatinsk, Omsk, Krasnoyarsk, Yakutsk, Nikolaevsk-on-Amur, Nagaevo, Petropavlovsk-Kamchatski, and Markovo stations). Quarterly mean TO deficiency at those stations was 10, 9, 9, 7, 7, 6, 8, 8, 7, and 8%, or 4.8, 3.8, 4.1, 2.7, 3.1, 2.7, 3.2, 3.8, 2.8, and 3.5 SD (standard deviations), respectively. Quarterly mean TO maximally exceeded the long-term mean at the Pechora station and amounted to 5%, or 2.1 SD.The lowest quarterly mean TO (300-340 DU) was observed over Central Asia and Kazakhstan. Quarterly mean TO values over European Russia, the south of Siberia, the Far East, Sakhalin, Kamchatka, and Chukchi Peninsula were 345-387 DU. The TO maxima were observed over the northern Ural and Siberian regions: 390-410 DU. A characteristic feature of the quarter is the TO increase from south to north.In this review for compiling TO maps, data from the UkrNIGMI station were used instead of those from a network station Kiev, about 30 km away from the UkrNIGMI station. Data from Vitim, Vladivostok, Lvov, Odessa, Ashkhabad, Guriev, and the Aral Sea stations were not used for the ozone field analysis in the second quarter of 2008 because of their low quality. In April the data from the Krasnovodsk station stopped coming.In April, monthly mean TO values over most of the area under control were below long-term means (Fig. 2b). The maximum monthly mean TO deficiency: 10%, or 2.1 SD was recorded at the Tsymlyansk station. The maximal exceeding of normal was noted at Pechora and Khanty-Mansisk stations: 2%, or 0.5 and 0.4 SD, respectively.