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The review is compiled according to the results of the total ozone (TO) monitoring system operation for the CIS and Baltic countries. The system functions in operational mode at the Central Aerological Observatory (CAO). The monitoring system uses the data from the national network equipped with the M-124 filter ozonometers, being under the methodological supervision of the Main Geophysical Observatory. The quality of the entire system functioning is operationally controlled in CAO by comparison with the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for each month of the first quarter of 2024 and for the first quarter as a whole. The data of routine surface ozone observations in the Moscow region are also summarized. [ABSTRACT FROM AUTHOR]

The review is compiled on the basis of the results of using the total ozone (TO) monitoring system for Russia and neighboring territories, which functions in operational mode at the Central Aerological Observatory. The monitoring system uses the data from the national network equipped with the M-124 filter ozonometers and operating under the methodological supervision of the Main Geophysical Observatory. The quality of functioning of the entire system is operationally controlled using the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for every month of the fourth quarter of 2023, for the fourth quarter, and for the whole year. The data of the routine observation of surface ozone in the Moscow region are also presented. [ABSTRACT FROM AUTHOR]

External verification based on ground-based data is commonly used to assess the accuracy of satellite products for total ozone. However, the spatial representativeness of ground-based observations at the pixel scale and the effects of the spatial mismatch between ground observations and satellite pixels are often overlooked. Therefore, this study focused on an Ozone Monitoring Instrument (OMI) and proposed a novel method to evaluate spatial representativeness using the total ozone product itself without relying on higher spatial resolution imagery from other sensors. A Pixel-level Spatial Mismatch Index (PSMI) was developed to quantify the peaks and stable intervals of the spatial response to the relative deviation of total ozone observations. The analysis revealed that increased uncertainty at the pixel edges can cause significant relative deviation, with the peak deviation occurring within a range of 4–7 km near the pixel boundary. The position of the high precision interval in PSMI was found to be 10 km, with mean values of 3.70 % and standard deviations of 3.45 % for the relative deviation. This interval is spatially distance-independent and can be observed on both sides of the pixel boundary. These findings highlight the importance of considering spatial patterns between satellite pixels and ground stations for external validation. Furthermore, avoiding a spatial response peak of the relative deviation at the pixel edge is crucial. Overall, this research provides new perspectives and insights for the verification of total ozone products. By considering these factors mentioned above, future verification of total ozone products can be improved, leading to enhanced their evaluation systems.

The review is compiled according to the results of exploiting the system of monitoring total ozone (TO) over Russia and adjoining territories, which is functioning in operational mode at the Central Aerological Observatory (CAO). The monitoring system uses the data from the national network equipped with M-124 filter ozonometers under the methodological supervision of the Main Geophysical Observatory. The quality of the functioning of the entire system is operationally controlled based on the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for each month of the third quarter of 2023 and for the third quarter. The data of routine observations of ground-level ozone in the Moscow region are also presented. [ABSTRACT FROM AUTHOR]

Total ozone time series in a metropolis in India were examined in the current study. The data explored are obtained through Brewer spectrophotometer, which counts photons with a photomultiplier to calculate UV irradiance in the spectrum and measures total ozone when the relative route of photons through the ozone layer (air mass) is 3.5 or less. The total ozone time series' uncertainty was thoroughly examined using the Dempster–Shafer method, and the association was also depicted using three-dimensional graphs. Finally, the Adam Optimisation Algorithm and the Rectified Linear Unit were used to demonstrate the prediction capability of the single layer Long Short-Term Memory model. [ABSTRACT FROM AUTHOR]

The review is compiled on the basis of the results of the total ozone (TO) monitoring over the CIS and Baltic countries functioning in operational mode at the Central Aerological Observatory (CAO). The monitoring system uses data from the national network equipped with M-124 filter ozonometers that is under the methodological supervision of the Main Geophysical Observatory. The system functioning is operationally controlled at the CAO by the comparison with the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for each month of the second quarter of 2023 and for the second quarter as a whole. The data of routine observations of surface ozone values in the Moscow oblast are also summarized. [ABSTRACT FROM AUTHOR]

The review is compiled on the basis of the results of operation of the total ozone (TO) monitoring system in the CIS and Baltic countries functioning in operational mode at Central Aerological Observatory (CAO). The monitoring system uses data from the national network equipped with M-124 filter ozonometers being under the methodological supervision of Main Geophysical Observatory. The quality of the functioning of the entire system is operationally controlled in CAO based on the OMI satellite equipment observations (NASA, USA). Basic TO observation data are generalized for each month of the first quarter of 2023 and for the first quarter. Data of routine observations of surface ozone values in the Moscow region are also presented. [ABSTRACT FROM AUTHOR]

In this paper, a method previously developed for reconstructing daily erythemal ultraviolet (UVery) doses in Novi Sad (Serbia) was improved and used for estimating daily UVery over the period 1971–2018. The proposed new method uses reanalysed total ozone column (TOC) data and snow cover as an input and is based on the empirical relationship between relative sunshine duration and relative UVery doses. Introducing reanalysed TOC data and snow cover data significantly improved the quality and accuracy of the reconstructed UVery time series, particularly in the winter season. The reconstructed time series revealed the statistically significant increase in summer and winter UVery in the 1980s and the first half of the 1990s (+8.78% and + 13.14% per decade, respectively), which was linked to the statistically significant decline in TOC (−4.13 and −7.36% per decade, respectively). The study focuses on days with high erythemal UV dose (highUVery), which is defined based on the 90th percentile of the daily UVery for each month. Moreover, the influence of low TOC, low cloud cover conditions, and high surface albedo on highUVery was analysed on a seasonal basis. The results of this study show that highUVery days increased from the 1980s, particularly strongly in the period of TOC depletion. A fraction of highUVery days in the last two decades was large (12.29%), which is higher than in the previous periods (6.97 and 8.68% in the period before and during TOC depletion, respectively). The occurrence of highUVery days was influenced mostly by low cloud cover (89.71% of days), and low TOC (82.23% of days). In the winter season, high surface albedo influenced the appearance of 19.18% of highUVery days. However, overall the interaction of low cloud cover and low TOC in all seasons most often led to the appearance of highUVery days. [ABSTRACT FROM AUTHOR]

The driving forces controlling the long-term total ozone change are investigated using the total ozone data from Edmonton (53.55°N, 114.0°W), Canada, over 1958–2018. By using the slow feature analysis method, the driving force signal for monthly mean total ozone time series is extracted. It is found that the driving force has fluctuated at higher values since the mid-1980s, and the corresponding total ozone has varied at lower values. These variation patterns indicate that the ozone loss since the mid-1980s is correlated with the higher values of the driving force. It is also found that the driving force exhibits sharp values following some explosive volcanic events, indicating that explosive volcanic eruptions act as a driving factor for ozone depletion. In order to analyze the scale structure of the driving force, the wavelet analysis method is applied. The results show that the spectral scales of the driving force peak at 2.4, 7.0, 21.4, 28.5, and 42.8 years. Among them, the 21.4 year periodicity, which corresponds to the 22-year solar magnetic cycle, is the basic one, and it modulates other mode of oscillations. More importantly, the 21.4 year cycle is modulated in amplitude by a signal with a much longer time scale. This long-scale modulating signal represents the impacts of the ozone depleting substances (ODSs) in the stratosphere, and it controls the long-term evolution of total ozone. Since the turn of the century, as the ODSs decline, a slow recovery of total ozone is expected. [ABSTRACT FROM AUTHOR]

Discrete wavelength radiance measurements from the Deep Space Climate Observatory (DSCOVR) Earth Polychromatic Imaging Camera (EPIC) allows derivation of global synoptic maps of total and tropospheric ozone columns every hour during Northern Hemisphere (NH) Summer or 2 hours during Northern Hemisphere winter. In this study, we present version 3 retrieval of Earth Polychromatic Imaging Camera ozone that covers the period from June 2015 to the present with improved geolocation, calibration, and algorithmic updates. The accuracy of total and tropospheric ozone measurements from EPIC have been evaluated using correlative satellite and ground-based total and tropospheric ozone measurements at time scales from daily averages to monthly means. The comparisons show good agreement with increased differences at high latitudes. The agreement improves if we only accept retrievals derived from the EPIC 317 nm triplet and limit solar zenith and satellite looking angles to 70°. With such filtering in place, the comparisons of EPIC total column ozone retrievals with correlative satellite and ground-based data show mean differences within ±5-7 Dobson Units (or 1.5–2.5%). The biases with other satellite instruments tend to be mostly negative in the Southern Hemisphere while there are no clear latitudinal patterns in ground-based comparisons. Evaluation of the EPIC ozone time series at different ground-based stations with the correlative ground-based and satellite instruments and ozonesondes demonstrated good consistency in capturing ozone variations at daily, weekly and monthly scales with a persistently high correlation (r2 > 0.9) for total and tropospheric columns. We examined EPIC tropospheric ozone columns by comparing with ozonesondes at 12 stations and found that differences in tropospheric column ozone are within ±2.5 DU (or ∼±10%) after removing a constant 3 DU offset at all stations between EPIC and sondes. The analysis of the time series of zonally averaged EPIC tropospheric ozone revealed a statistically significant drop of ∼2–4 DU (∼5–10%) over the entire NH in spring and summer of 2020. This drop in tropospheric ozone is partially related to the unprecedented Arctic stratospheric ozone losses in winter-spring 2019/2020 and reductions in ozone precursor pollutants due to the COVID-19 pandemic.

Objective. Provide an analysis of the total ozone variations over Vernadsky Antarctic station (Faraday Base until 1996) from long-term ground-based and satellite series. Study the discrepancies between the data of different instruments. Methods. Data visualization followed by analysis, statistical treatment of the Vernadsky Dobson spectrophotometer observations and satellite total ozone series. Results. Satellite and ground-based measurements of total ozone over Vernadsky station have confirmed the stabilization in the ozone layer in the stratosphere over Antarctica from the early 2000s. British Faraday Base observations have retrieved an ozone spring maximum during the 1950s–1970s with a sharp decrease in the August–October values in the 1980s–1990s. That changed substantially total ozone seasonal cycle. Satellite overpasses and model data based on satellite measurements have been analyzed. It is shown that typical discrepancies between the Ozone Monitoring Instrument (OMI) model and the Vernadsky Dobson daily means are mainly in the range of 20 DU. Larger deviations are rare and are observed predominantly on the beginning and at the end of the observational season. Seasonal means and standard deviations for the model–Dobson differences were calculated that demonstrates worse correspondence of the OMI model with Vernadsky Dobson data during separate years, in particular 2009–2010. Conclusions. Both Dobson and satellite ozone data over Faraday/Vernadsky station have shown the total ozone decrease during the 1980s–1990s (mainly in spring) with a following stabilization since year 2000. Comparison between the ground-based data and models calculated from satellite measurements indicates better correspondence of the Dobson and GOME2 results relatively the OMI ones. There are evidences that individual Dobson measurements underestimate to some degree total ozone on the beginning of observational season at high solar zenith angles and the low total ozone values.

Data on the effect of global warming on the ozone layer and the intensity of near-surface near-noon UVB radiation in 2100 compared to the year 2000 are presented. Changes in the ozone layer are calculated at a latitude of 50° N for January and June of 2100 when compared with 2000 using the one-dimensional photochemical model, as well as the SOCRATES interactive two-dimensional photochemical model, using greenhouse gas concentrations given in the scenarios of the Intergovernmental Panel on Climate Change (IPCC) RCP 4.5 and PCP 6.0. Surface UVB radiation fluxes for the above conditions are calculated using a program developed at the Norwegian Institute for Atmospheric Research in 2005 (by Ola Engelsen). [ABSTRACT FROM AUTHOR]

The variability of Arctic total ozone in the winter of 2015/2016 is studied using the data of the national network equipped with M-124 filter ozonometers and satellite monitoring. The first ozone mini-hole that emerged in the first half-year over the whole history of observations (developed at the end of January 2016) is analyzed. The reasons for the total ozone variability over Russia in the first quarter of 2016 are analyzed, and the comparison with the significant Arctic ozone anomalies in 1996/1997 and 2010/2011 is presented. [ABSTRACT FROM AUTHOR]

Изменение общего содержания озона над станцией «Академик Вернадский» / «Фарадей» исследуется с 1996 года, после передачи Украине станции Британской Антарктической службы (БАС). В последние десятилетия отмечается заметное истощение озонового слоя над Антарктидой. Сравнение среднего годового хода общего содержания озона по измерениям на станции «Академик Вернадский» / «Фарадей» за периоды 1972 - 1994 гг. и 1995 - 2012 гг. показали, что озоновая дыра в период 1972-1994 гг. не проявлялась. В статье предлагается новый подход к классификации кривых годового хода общего содержания озона над Украинской Антарктической станцией (УАС) в последние десятилетия.

In this study, the spatio-temporal variability of aerosol optical depth (AOD), total column ozone (TCO), and total column NO2 (TCN) was identified over East Asia using long-term datasets from ground-based and satellite observations. Based on the statistical results, optimized spatio-temporal ranges for the validation study were determined with respect to the target materials. To determine both spatial and temporal ranges for the validation study, we confirmed that the observed datasets can be statistically considered as the same quantity within the ranges. Based on the thresholds of R2>0.95 (temporal) and R>0.95 (spatial), the basic ranges for spatial and temporal scales for AOD validation was within 30 km and 30 min, respectively. Furthermore, the spatial scales for AOD validation showed seasonal variation, which expanded the range to 40 km in summer and autumn. Because of the seasonal change of latitudinal gradient of the TCO, the seasonal variation of the north-south range is a considerable point. For the TCO validation, the north-south range is varied from 0.87° in spring to 1.05° in summer. The spatio-temporal range for TCN validation was 20 min (temporal) and 20–50 km (spatial). However, the nearest value of satellite data was used in the validation because the spatio-temporal variation of TCN is large in summer and autumn. Estimation of the spatio-temporal variability for respective pollutants may contribute to improving the validation of satellite products.

A study of the Antarctic ozone hole has been made with a three-dimensional chemical transport model (CTM) using a linearized photochemistry for ozone. The tracer model uses the winds and convection from the Goddard Institute for Space Studies general circulation model (8° × 10° × 23 layers). The general circulation model (GCM) develops an Antarctic circumpolar vortex in early winter with strong westerlies that reverse in austral spring; the circulation compares favorably with the observed climatologies. A 4-year control run of the CTM with annually repeating winds produces ozone distributions that compare reasonably with the observed climatology. We examine different linearizations of the ozone chemistry and show that the calculated column ozone is sensitive to the chemical time constants in the lower stratosphere. In separate numerical experiments a hypothetical Antarctic ozone “hole” is induced on September 1 and on October 1; the CTM is integrated for 1 year with a linearized model that assumes standard photochemistry, not including the heterogeneous reactions and unusual chemistry associated with formation of the ozone hole. The initial depletion, assumed to be 90% of the O3poleward of 70°S between 22 and 200 mbar, amounts to about 5% of the total O3 in the southern hemisphere. As the vortex breaks down and the ozone hole is dispersed, significant depletions to column ozone, of order 10 Dobson units (3%) occur as far north as 40°S during austral summer. One year later, only 30% of the original depletion remains, mostly below 100 mbar and poleward of 30°S. The October 1 initialization is continued for a second year, the ozone hole being reinduced 1 year later with the same parameterization. The cumulative effects from the year before are noticeable but add only 20% to the depletion. A budget analysis for the southern high-latitude stratosphere (10–350 mbar × 31°–90°S) indicates the ozone hole is replenished equally by photochemical regeneration and by reduced transport of ozone into the troposphere, with a lesser fraction being filled in by an increased flux from the tropical stratosphere.

Abstract: A new technique has been developed to obtain the total ozone content (TOC) under cloudy conditions from the spectra of outgoing thermal IR radiation measured by a satellite IRFS‑2 spectrometer. Analysis of the technique errors has shown that the differences between the obtained TOC and independent satellite (OMI) and ground-based (Dobson, Brewer, and M-124 instruments) measurements are usually 3-5%. The highest differences (up to 10%) are observed in the southern polar latitudes in the presence of an ozone hole over Antarctica. IRFS‑2 allowed the study of ozone miniholes over Russia in the first quarter of 2016. The measurements show an almost twofold decrease in TOC on certain days. [ABSTRACT FROM AUTHOR]

Abstract Spectral UV records of solar irradiance at stations over Europe, Canada, and Japan were used to study long-term trends at 307.5 nm for a 25-year period, from 1992 to 2016. Ground-based measurements of total ozone, as well as satellite measurements of the Aerosol Index, the Total Cloud Cover and the surface reflectivity were also used in order to attribute the estimated changes of the UV to the corresponding changes of these factors. The present study shows that over the Northern Hemisphere, the long-term changes in UV-B radiation reaching the Earth's surface vary significantly over different locations, and that the main drivers of these variations are changes in aerosols and total ozone. At high latitudes, part of the observed changes may also be attributed to changes in the surface reflectivity. Over Japan, the UV-B irradiance at 307.5 nm has increased significantly by ∼3%/decade during the past 25 years, possibly due to the corresponding significant decrease of its absorption by aerosols. It was found that the greatest part of this increase took place before the mid-2000s. The only European station, over which UV radiation increases significantly, is that of Thessaloniki, Greece. Analysis of the clear-sky irradiance for the particular station shows increasing irradiance at 307.5 nm by ∼3.5%/decade during the entire period of study, with an increasing rate of change during the last decade, possibly again due to the decreasing absorption by aerosols. [ABSTRACT FROM AUTHOR]

This study introduces the measurement of the total ozone column using Differential Optical Absorption Spectroscopy (DOAS) analysis of direct-sun spectra recorded by the Phaethon system. This methodology is based on the analysis of spectra relative to a reference spectrum that has been recorded by the same instrument. The slant column density of ozone associated with the reference spectrum is derived by Langley extrapolation. Total ozone data derived by Phaethon over two years in Thessaloniki are compared with those of a collocated, well-maintained and calibrated, Brewer spectrophotometer. When the retrieval of total ozone is based on the absorption cross sections of (Paur and Bass, 1984) at 228 K, Phaethon shows an average overestimation of 1.85 ± 1.86%. Taking into account the effect of the day-to-day variability of stratospheric temperature on total ozone derived by both systems, the bias is reduced to 0.94 ± 1.26%. The sensitivity of the total ozone retrieval to changes in temperature is larger for Phaethon than for Brewer. [ABSTRACT FROM AUTHOR]