engleski

Analysis of ozone data from the Puntijarka station for the period between 1989 and 2009

Monitoring data on ambient ozone collected at the Puntijarka station located on the mountain Medvednica 980 m a.s.l. and 10 km to the north of the Croatian capital Zagreb during a 21-year period (1989–2009) have been analysed in order to check whether any regularities such as periodicities or trends in the data could be detected. Only two types of cycles could be observed: an annual cycle with higher ozone fractions during spring and summer and a diurnal cycle with the highest values at noon and in the early afternoon. Both can be related to insolation with the same periodicity confirming the photochemical nature of ozone formation. Conclusions about trends are less pronounced ; for the first decade of the observational period no significant trend was found and for the second decade there was a significantly negative trend of −1.38 ppb yr−1.

tropospheric ozone ; ozone trend ; background ozone ; frequency analysis ; photochemical pollution ; long-term data analysis

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