Spectral analysis of boundary layer ozone data from the EUROTRAC TOR network

Abstract

[1] Data obtained during many years of continuous ozone monitoring at 12 selected EUROTRAC-TOR (Eureka environmental project: European experiment on Transport and transformation of environmentally relevant trace Constituents in the troposphere over Europe, subproject Tropospheric Ozone Research) network stations were analyzed by applying Fourier transformation (FT). FT averaged over the years, autocorrelation functions and FT of such functions were calculated for each site. As expected, strong frequency signals are found for the 1 year and 1 day periods. The relative intensity of the 1 day peak can be correlated with the intensity of local photochemical pollution as represented by a photochemical pollution index. A collective FT spectrum for seven European stations was calculated. This comparison confirms the existence of a common variation in ozone volume fractions with quasi-periods ranging between 7 and 44 days. These frequencies are most probably connected with quasi-cyclic synoptic scale meteorological influences. A comparison of meteorological data from the station Zugspitze showed similar periodicities.

Spectral windowing application to study surface ozone variability over Europe

“…The following groups of periods, having identifiable responses in intra‐annual variability of surface ozone concentration, were chosen: 90–31 days, 30–19 days, 18–8 days and 7–1 days. Some periods in these ranges were found in the spectra of observed surface ozone time series at several sites of the TOR‐2 project [ Cvitaš et al , 2004, and references therein]. Similar periods were mentioned in the classification of atmospheric motions by Tiedtke [2002] and they are applied in dynamical meteorology .…”

“…Periods of 18–8 days are considered to be connected with change of ozone in weather patterns (system “cyclone‐anticyclone”) and partly caused by planetary waves propagation with big wave numbers. The periods of this scale were reported for the most European sites by Cvitaš et al [2004] and Zvyagintsev [2004]. In the paper this group of periods is referred to as scale 3.…”

“…The periods of variability corresponding to planetary waves were recognized at this timescale for the first time for total ozone content by Khrgian and Kuznetsov [1981]. There are a numbers of other periods at this scale that have also been observed at the low‐altitudal sites [ Cvitaš et al , 2004].…”

Observations Utilizing Korea Ocean Research Stations and their Applications for Process Studies

“…8, the scatterplots of the O 3 versus the PM 2.5 concentrations at the two sites are quite similar to one another. Contamination was removed by 2 filters at 10 neighboring values (Cvitaš et al 2004). There were found to be two distinct regimes for the formation and accumulation of PM 2.5 and O 3 in the atmosphere, albeit there were limitations associated with temporal coverage of the data.…”

Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

“…Thus, raw data were first filtered manually and then the measurements bigger and smaller than 2σ (standard deviation) of the average for 10 neighboring values were eliminated. This method is widely used to remove local effects for long-term period measurement (Cvitaš et al, 2004). Statistical analysis was conducted using R (v.3.0.1) (R Core Team, 2014).…”