Spectral windowing application to study surface ozone variability over Europe

Abstract

Spectral filtering technique is applied to analyze spatial and temporal peculiarities of the surface ozone variability over Europe. Different ranges of intra‐annual variability are separated, and their contribution in total observed variability is estimated. Data from 83 sites of the EMEP ozone‐monitoring network are used to study periods of 90–31 (scale 1), 30–19 (scale 2), 18–8 (scale 3), and 7–1 (scale 4) days. Spatial fields and seasonal variability of the selected scales are discussed. The obtained variability fields are spatially nonuniform over Europe and include some peculiarities for individual scales. The contribution of variability at scale 3 is estimated to be maximal (up to 10% of total variability) among the studied ones. Variability at all the scales is 10–15% less in the Alpine regions in comparison with other continental areas of low altitude. Maximal variability at all studied scales is observed in summer. Lines of equal variability values in most cases are parallel to the border of continent and exhibit a north‐south gradient.

Periodic variability of surface ozone concentration over western and central Europe from observational data

“…The presence of higher harmonics shifts the period of observations of the annual ozone maximum towards summer by three months; sometimes two maximums are formed in the annual trend [1,7,12]. Spatial features of the amplitude of the first harmonic are very similar to the features of the distribution of the surface ozone concentration variability in different spectral ranges [13]. Figure 5 shows the distribution of basic characteristics of a daily ozone trend.…”