Measurements and Modelling of Total Ozone Columns near St. Petersburg, Russia

Abstract

The observed ozone layer depletion is influenced by continuous anthropogenic activity. This fact enforced the regular ozone monitoring globally. Information on spatial-temporal variations in total ozone columns (TOCs) derived by various observational methods and models can differ significantly due to measurement and modelling errors, differences in ozone retrieval algorithms, etc. Therefore, TOC data derived by different means should be validated regularly. In the current study, we compare TOC variations observed by ground-based (Bruker IFS 125 HR, Dobson, and M-124) and satellite (OMI, TROPOMI, and IKFS-2) instruments and simulated by models (ERA5 and EAC4 re-analysis, EMAC and INM RAS—RSHU models) near St. Petersburg (Russia) between 2009 and 2020. We demonstrate that TOC variations near St. Petersburg measured by different methods are in good agreement (with correlation coefficients of 0.95–0.99). Mean differences (MDs) and standard deviations of differences (SDDs) with respect to Dobson measurements constitute 0.0–3.9% and 2.3–3.7%, respectively, which is close to the actual requirements of the quality of TOC measurements. The largest bias is observed for Bruker 125 HR (3.9%) and IKFS-2 (−2.4%) measurements, whereas M-124 filter ozonometer shows no bias. The largest SDDs are observed for satellite measurements (3.3–3.7%), the smallest—for ground-based data (2.3–2.8%). The differences between simulated and Dobson data vary significantly. ERA5 and EAC4 re-analysis data show slight negative bias (0.1–0.2%) with SDDs of 3.7–3.9%. EMAC model overestimates Dobson TOCs by 4.5% with 4.5% SDDs, whereas INM RAS-RSHU model underestimates Dobson by 1.4% with 8.6% SDDs. All datasets demonstrate the pronounced TOC seasonal cycle with the maximum in spring and minimum in autumn. Finally, for 2004–2021 period, we derived a significant positive TOC trend near St. Petersburg (~0.4 ± 0.1 DU per year) from all datasets considered.

An Unprecedented Arctic Ozone Depletion Event During Spring 2020 and Its Impacts Across Europe

“…The harmonized data set of the Norwegian GUV network showed a bias of 0.3% with respect to Brewers that could vary up to 2% (Svendby et al, 2021). The filter ozonometer M-124 used in Saint Petersburg showed no bias with respect to Dobson measurements (Nerobelov et al, 2022) while a similar comparison made at Moscow (Table 1) indicates a discrepancy of 2%.…”

“…The majority of instruments in the WOUDC database are Brewer and Dobson spectrophotometers (see Table 1) while some of the stations are equipped with SAOZ spectrometers (Pommereau & Goutail, 1988), filter ozonometers M‐124 (Nerobelov et al., 2022), and Microtops II (Morys et al., 2001). All above listed instruments are well characterized and periodically calibrated against reference devices to provide reliable data.…”

Six Years of IKFS-2 Global Ozone Total Column Measurements

“…According to [28], the mean differences and SDDs between several satellite data products (IKFS-2, OMI, TROPOMI) and ground-based standard measurements (Dobson) near St. Petersburg for different periods in the timespan of 2015-2020 constituted 1.8-2.4 and 3.3-3.7%.…”