The study aims to develop a methodology for identifying and correcting drift in the quality of orbital data to improve the accuracy of long-term trend estimates and enhance the representativeness of orbital monitoring. We establish the presence of unidirectional, statistically significant drift in the difference between satellite instrument readings and ground-based observations. We compare the last two versions of methane (CH4) measurements from the Atmospheric InfraRed Sounder (AIRS)—specifically, Level 3 versions 6 and 7 (“IR-AIRS Only”)—with data from 18 ground-based stations of the Network for the Detection of Atmospheric Composition Change (NDACC) and 11 stations of the Total Carbon Column Observing Network (TCCON) for the 2003–2022 period. We determine that adjusting ground-based measurement data to sea level using the barometric formula, which is a necessary step for proper validation, results in significant errors, especially at high altitudes. It is proposed that such an adjustment should be based on pressure measured directly at a station. Implementing this over the examined period, we determine that the residual drift of the satellite spectrometer (Satellite Spectrometer Drift or SSD) is negative and equal to 1.64 × 1014 molecules/cm2 per day or 7.62 × 10−6 ppm per day for AIRS v6 and 7.20 × 10−6 ppm per day for AIRS v7. The correction implementation significantly improves the correspondence between AIRS v6 and v7 methane data and NDACC data, resulting in close estimates of methane trends from satellite and ground-based measurements. The robustness of the proposed correction has been demonstrated by the improvement in the consistency of station-by-station trend estimates obtained for corrected AIRS data and independent TCCON ground-based observations.

We analyzed AIRS CH4 volume mixing ratio (VMR) Standard L3 v6/v7 IR-Only Daily products and ground-based measurements from 16 stations of the Network for the Detection of Atmospheric Composition Change (NDACC) at 24 pressure levels from 1000 to 1 mbar. We assessed the dependence of maximum AIRS sensitivity on latitude. At high latitudes, the zone of maximum sensitivity is closer to the surface, at 700–500 mbar; in mid-latitudes, it is 500–250 mbar; and in tropical and subtropical regions, good initial agreement between satellite and ground-based data is observed at 400–200 mbar for both AIRS product versions. At the vast majority of pressure levels and all comparison sites, a unidirectional negative drift in the difference between satellite and ground-based measurements (i.e., discrepancy drift) was observed. Drift coefficients were calculated for each statistically supported pressure level. Two regions of maximum drift were identified: one in the lower atmosphere (925–850 mbar) and another near 50 mbar. The smallest drift was observed at 400–200 mbar. As the main result of the study, we developed and applied correction factors for all 23 AIRS v6 and v7 levels. Using these coefficients led to much better agreement between long-term methane trends from ground-based and satellite measurements and to higher correlation coefficients across all comparison sites.

This report presents the results of a comprehensive analysis of spectroscopic long-term data sets on CO total content (CO TC) at stations of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), in Moscow and Moscow oblast. The long-term variability of CO TC and meteorological parameters in atmospheric boundary layer were investigated. A decrease in the average TC CO annual values in 2000–2023 was found for Moscow (–2.23 ± 0.36%/year) and for Zvenigorod Scientific Station (ZSS) (‒1.12 ± 0.33%/year). The CO trend characteristics in both sites in different seasons and periods are demonstrated and discussed. After about 2007–2008, the rate of CO TC reduction decreased at both sites. In 2008–2023 at the ZSS no significant changes in CO TC in the summer and autumn months were found: trend was near zero (-0.04±0.81%/year). An increase in the wind speed in the atmospheric boundary layer of Moscow in different periods of 2008–2022 at a rate of 0.66±0.55%/year has been determined. At the same time, no statistically significant changes in wind speed were found in Kaluga oblast (0.12±0.56%/year). The results indicate the influence of the climatic (meteorological) factor on air quality in Moscow. Study was supported by Russian Science Foundation, Project No 20-17-00200.

Based on the analysis of orbital measurements and GEOS-Chem model calculations with different anthropogenic and wild-fires emission scenarios, a study of trends in the total content of CO and CH4 in different periods and seasons of 2003-2023 for the Eurasia domain, -20°E - 180°E, 0°N - 80°N. A response of CO trends to climate change was estimated. Data from the orbital AIRS instrument and ground-based spectrometers were used as experimental information to assess atmospheric composition trends.A good agreement has been established between estimates obtained from the orbital data and from simulations. However, certain regional features of the discrepancies have been identified and are associated with the inaccuracy of specifying the spatial distribution and integral power of anthropogenic CO, CH4 and another species emission and their trends for Russia, South-East Asia and other regions of Eurasia. These emission uncertainties affect the accuracy of model calculations.In general, according to average annual estimates, CO TC trends over entire Eurasia for 2000-2023 was slightly negative (~ 0.5-1.2 %/year depending on the region); however, after approximately 2008 the downward trend slowed down, and in some areas the CO TC began to rise.Thus, a positive change in CO TC trends after about 2008 was established. In the entire domain under study, this change was about 2–3%/year, according both experimental and model estimates. In autumn months of 2008-2023 the increase in CO TC was established over almost the entire Eurasia, including Arctic regions and Europe. This growth (at least in Europe) cannot be explained by either anthropogenic emissions or releases from wild-fires. A possible reason for this rising may be the formation of additional CO from methane, the increase in concentrations of which began around the same time (after 2007), and change in the source/sink ratio for CO.Additionally, to assess the parameters of correspondence between orbital and ground-based measurements, we have compared the trend estimates using only synchronous orbital and ground-based CO and CH4 observations and obtained the drift of the difference between them.The study was supported by Russian Science Foundation under grant №20-17-00200.

This study considers methods for assessing the quality of orbital observations, quantifying drift over time, and the application of correction methods to long-term series. AIRS v6 (IR-only) satellite methane (CH4) and carbon monoxide (CO) total column (TC) measurements were compared with NDACC ground station data from 2003 to 2022. For CH4, negative trends were observed in the difference between satellite and ground measurements (AIRS-GR) at all 18 stations (mean drift: 1.69 × 1014 ± 0.31 × 1014 molecules/cm2 per day), suggesting a shift in the orbital spectrometer parameters is probable. The application of a dynamic correction based on this drift coefficient significantly improved the correlation with satellite data for both daily means and trends at all stations. In contrast, AIRS v6 CO measurements showed a strong initial correlation (R = 0.93 for the entire dataset, and R ~ 0.8–0.95 for separate stations) without systematic drift, i.e., the trends of AIRS-GR at individual sites were oppositely directed and statistically insignificant. Therefore, the AIRS v6 CO TC satellite product does not require additional correction within this method. The developed methodology for satellite data verification and correction is supposed to be universal and applicable to other long-term orbital observations.

The impact of measures to limit the COVID-19 pandemic on atmospheric composition and emissions of atmospheric impurities in scales of the whole Northern Eurasia and Moscow region was assessed. The effect of restrictive measures on the surface NO2 and CO concentrations and columns as well as aerosol optical depth AOD was investigated. Significant but short-time changes of NO2 tropospheric column spatial distribution comparing to 2019 reflecting the pandemic extension across Eurasia and reduction of regional emissions due to lockdowns were revealed for the first half of 2020 using TROPOMI data. Lockdown period in Moscow coincided with substantial decrease in both NOx and CO surface concentrations, and CO total content. However, the meteorological parameters in 2020 strongly differed from ones in previous years and favored Moscow regional air quality improvement in the spring months of 2020. Therefore, reduction of air pollution due to the lockdown is likely to be within interannual variability due to meteorological situation.

An Erratum to this paper has been published: https://doi.org/10.1134/S1024856024330029

An Erratum to this paper has been published: https://doi.org/10.1134/S1024856024330029

Results of the analysis of interannual, seasonal, and diurnal variations in the ratios of the mixture of CH 4 , CO 2 , CO, benzene, and δ13C–CH 4 in the surface air of Moscow based on the measurements at the station of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), in 2018–2020 are presented. The annual maximum concentration of CH 4 , CO 2 , and CO (>2.2, 430, and 0.20 ppm, respectively) occurs in the winter months due to the seasonal increase in the anthropogenic load from the main sources of urban pollution: motor transport and thermal power plants and a decrease in the role of vertical air mixing. The greatest contribution of local and remote microbial sources to the CH 4 concentration is noted in the summer months against the background of low δ13C–CH 4 values (–50 to –60‰). In all seasons, CH 4 , CO 2 , and CO ground level peaks lasting up to several hours are due to the transport from industrial sites in the E–SE sector. The calculated mean emission ratios in urban air were CH 4 /benzene = 0.52–0.54 ppm/ppb, CH 4 /СО = 0.56–0.75 ppm/ppm, CO 2 /benzene = 77–93 ppm/ppb, CO 2 /СО = 81–131 ppm/ppm, and CO/benzene = 0.65–1.11 ppm/ppb. These ratios characterize the predominant contribution of emissions from motor transport and the heat and power equipment and can be used to refine the absolute values of emissions, including those on the basis of existing inventories of sources of anthropogenic air pollution.

Near-surface observations of air mixing ratios of CH4, CO2, CO, benzene, and δ13C–СH4 at the IAP-RAS site in Moscow for years 2018–2020 are analyzed to describe typical interannual, seasonal, and diurnal variations. The highest mixing ratios of CH4, CO2, and CO (above 2.2, 430, and 0.2 ppmv, respectively) are mostly observed in winter as a result of the seasonal maxima in the emissions of these gases from motor transport and energy sectors and the slow removal of the emissions from the near-surface air due to suppressed turbulent vertical mixing in the cold season. The highest impact of local and distant microbial emissions on the CН4 mixing ratios is observed in summer, as follows from the low δ13C–СH4 values from –50 to –60‰. The highest increase in the mixing ratios of all the measured species is associated with air transport from the industrial area located at the east – southeast from the site. The estimated emission ratios CH4/benzene = = 0.52–0.54 ppmv/ppbv, СH4/СО = 0.56–0.75 ppmv/ppmv, СО2/benzene = 77–93 ppmv/ppbv, СО2/СО = = 81–131 ppmv/ppmv, СО/benzene = 0.65–1.11 ppmv/ppbv show the prevailing contribution of emissions from motor transport and energy sectors to the content of trace gases in the near-surface air in Moscow and are consistent with other similar estimates published on the basis of observations in large cities.

The rates of ozone production (P) and sink (L) and total peroxide (OX) content are assessed with the use of the photostationary state approach from measurements of ozone (O3) and nitrogen oxides (NO and NO2) at the Zotino Tall Tower Observatory (ZOTTO), central Siberia, in 2007–2014. Mean daily cycles of the above quantities for May–September cloud-free days peak at 6 ppb/hour (P), 1.4 ppb/hour (L), and 115 ppb ([OX]) between 11:00 and 15:00 LT. The linear dependence of P on [NOx] is derived in the range of measured NOx mixing ratios from 0.2–0.8 ppb, suggesting for NOx-limiting conditions of ozone production, with the slope rate P(O3)/[NOx] estimated at 13 (ppb/h)/ppb. The estimated high OX levels along with the condition P ⪢ L manifest for high rates of the in situ oxidation of biogenic volatile organic compounds and photochemical ozone generation. The surface air layer can be treated as an ozone source for the atmospheric boundary layer over remote areas of Siberia at NOx concentrations corresponding to conditions of both regionally background air and weakly polluted air. The obtained estimates indicate the significant role of regional NOx emissions in the ground-level ozone budget and necessity of taking this factor into account when forecasting ecological risks in Siberian regions that are commonly considered pollution-free.

Measurements of near-surface methane (CH4) mixing ratio and its stable isotope 13C were carried out from January 2018 to December 2020 at the A.M. Obukhov Institute of Atmospheric Physics (IAP) research site in the center of Moscow city. The data show moderate interannual variations in monthly mean CH4 with maximum values being observed predominantly in winter (2.05–2.10 ppmv on average). The most δ13C depleted CH4 (up to −56‰) is observed in summer and autumn following seasonal decrease in traffic load in the city. The highest CH4 concentrations (>2.2 ppmv) were likely to be caused by air transport from the E–SE sector where potentially large microbial CH4 sources are located (landfills and water treatment plants, Moscow River). Keeling plots of these episodes in different seasons of 2018–2020 showed δ13C isotopic signatures of about −58–−59‰ for the spring–autumn period and −67‰ for winter. A good correlation was observed between CH4 and other pollutants: CO2, CO, and benzene in daytime (10:00–19:00) hours (R > 0.7). Contribution of urban methane emissions due to vehicle exhausts (∆[CH4]auto) and microbial activity (∆[CH4]micro+) along with regional baseline mixing ratios of CH4 ([CH4]base) and CO ([CO]base) were estimated from the linear orthogonal regression analyses of the measured daytime mixing ratios. A significant role of microbial methane in the formation of CH4 maximums in Moscow was revealed. Contributions of the upwind continental CH4 and CO sources to the measured species levels were estimated through comparison with the Mace Head site data representative for the Northern Hemisphere baseline air. The study provides, for the first time, important insights into the long- and short-term variations of CH4 levels in Moscow in connection to the local (urban) emissions and long-range transport from upwind continental sources. The results will contribute to elaboration of a default emission inventory in air quality modeling and help to identify the areas for targeted mitigation efforts.

На основе глобальной транспортно-химической модели GEOS-chem проведены оценки вкладов антропогенных и природных эмиссий метана (CH4) в Северной Евразии (> 40° с.ш.) и на территории России в его приземное содержание на региональных измерительных станциях ZOTTO, Териберка и Тикси в 2007-2018 гг. Результаты модельных расчетов хорошо согласуются c предложенным полуаналитическим решением, основанным на разделении полного вклада (атмосферного отклика) на синоптическую и глобальную компоненты. На временах адвекции, соответствующих синоптическому временному интервалу, среднегодовой вклад антропогенных эмиссий на территории России в содержание метана в ZOTTO (38,6 млрд-1) более чем в 2 раза превышает вклад эмиссий из источников Западной Европы (17,7 млрд-1), тогда как для арктических станций влияние российских и европейских источников сопоставимо (19,5 и 12,4 млрд-1 соответственно). Сравнительно низкий, по сравнению с ZOTTO, вклад континентальных эмиссий в приземное содержание метана и его годовую изменчивость на арктических станциях обусловлен бóльшими временами адвекции из регионов-источников. Близость модельных величин откликов для Териберки и Тикси объясняется сравнительно однородным (циркумполярным) распределением антропогенного и биогенного сигналов в полярных широтах. Contribution of anthropogenic and wetland methane emissions in North Eurasia (> 40°N) and Russia into the near-surface CH4 abundance at ZOTTO, Teriberka, and Tixi measurement sites is quantified using GEOS-chem global chemical-transport model. Numerical results agree well with the proposed semi-analytical solution, in which the total response in the CH4 level at a given site is represented as the sum of direct (synoptic) and global terms. The annual average direct contribution of Russian anthropogenic emissions into CH4 mixing ratio measured at ZOTTO (38.6 ppbv) is twice as large as that for Western Europe sources (17.7 ppbv). For the Arctic sites, the anthropogenic input from Russian and European anthropogenic sources is roughly similar (19.5 ppbv and 12.4 ppbv, correspondingly). The input from continental sources into methane abundance and its annual variability at the Arctic sites are generally lower compared to those at the ZOTTO site due to larger transport times from upstream CH4 source regions. Atmospheric responses in methane levels at the Teriberca and Tixi sites to CH4 continental sources are found to be very close, which is explained by spatial homogenization of the anthropogenic and biogenic signals in high latitudes.

Results of the analysis of interannual, seasonal, and diurnal variations in the ratios of the mixture of CH4, CO2, CO, benzene, and delta C-13-CH4 in the surface air of Moscow based on the measurements at the station of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), in 2018-2020 are presented. The annual maximum concentration of CH4, CO2, and CO (>2.2, 430, and 0.20 ppm, respectively) occurs in the winter months due to the seasonal increase in the anthropogenic load from the main sources of urban pollution: motor transport and thermal power plants and a decrease in the role of vertical air mixing. The greatest contribution of local and remote microbial sources to the CH4 concentration is noted in the summer months against the background of low delta C-13-CH4 values (-50 to -60 parts per thousand ). In all seasons, CH4, CO2, and CO ground level peaks lasting up to several hours are due to the transport from industrial sites in the E-SE sector. The calculated mean emission ratios in urban air were CH4/benzene = 0.52-0.54 ppm/ppb, CH4/CO = 0.56-0.75 ppm/ppm, CO2/benzene = 77-93 ppm/ppb, CO2/CO = 81-131 ppm/ppm, and CO/benzene = 0.65-1.11 ppm/ppb. These ratios characterize the predominant contribution of emissions from motor transport and the heat and power equipment and can be used to refine the absolute values of emissions, including those on the basis of existing inventories of sources of anthropogenic air pollution.

We present the most significant results of Russian scientists in the field of atmospheric ozone research for 2019–2022 and examine observations of tropospheric ozone, its distribution and variability on the territory of the Russian Federation, its relation with atmospheric parameters, modeling of formation processes, and its impact on public health. The state of stratospheric ozone over Russia, modeling of processes in the ozonosphere, and methods and instruments being developed are also analyzed. The review is a part of Russia’s national report on meteorology and atmospheric sciences, which was prepared for the International Association of Meteorology and Atmospheric Sciences (IAMAS). It has been reviewed and approved at the 28th General Assembly of the International Union of Geodesy and Geophysics (IUGG).

The review contains the most significant results of the work of Russian scientists in the field of atmospheric ozone research performed in 2019–2022. It considers observations of tropospheric ozone, its distribution and variability in the territory of the Russian Federation, the relationship with atmospheric parameters, modeling of education processes and the impact on public health. The state of stratospheric ozone over the region, modeling of processes in the ozonosphere, developed methods and instruments were also analyzed. The review is part of Russia’s national report on meteorology and atmospheric sciences, which was prepared for the International Association for Meteorology and Atmospheric Sciences (IAMAS). The report was reviewed and approved at the XXVIII General Assembly of the International Geodetic and Geophysical Union (IUGG).

Based on the analysis of orbital measurements, as well as GEOS-Chem model calculations, a study of trends in the total content of CO, CH4 and NO2 in different periods and seasons of 2003-2022 was made for the Eurasia domain, -20°E - 180°E, 0°N - 80°N. Data from the AIRS and OMI instruments were used as orbital information.Before calculating the trend distributions, we compared the trend estimates obtained from orbital and ground-based measurements using only synchronous observations, i.e., days when the measurements were carried out by both orbital (AIRS, OMI) and ground-based (IAP RAS and NDACC stations) instruments.A good agreement has been established between trend distributions obtained from the orbital data and the same distributions obtained from the GEOS-Chem model calculations.In general, according to average annual estimates, trends over most of Eurasia regions in the period 2003-2022 was negative; however, after 2008 the downward trend slowed down, and in some areas the CO content began to rise.Thus, a positive trend (change) in CO TC trends after about 2008 was established. In the entire domain under study, this change was about 2–2.5%/year. In the autumn months of 2008-2022 (including November) increase in CO TC was established over almost the entire Eurasia, including Arctic regions and Europe. This growth (at least in Europe) cannot be explained by either anthropogenic emissions or releases from fires. A possible reason for this rising may be the formation of additional CO from methane, the increase in concentrations of which began around the same time (after 2007), and change in the source/sink ratio for CO.Based on GEOS-Chem calculations with different scenarios for specifying anthropogenic emissions and emissions from fires, the response of CO trends to climate change was calculated. The study was supported by Russian Science Foundation under grant №21-17-00210.

Anthropogenic pollution of the atmosphere with organic and inorganic gaseous species has been studied using constant high-quality monitoring of the atmosphere composition both in megacity of Moscow and in its countryside. The article considers continuous measurements of the main climatically and chemically active atmospheric gaseous species concentrations, including volatile organic compounds. The main attention is paid to the comparative analysis, mainly between the megacity and its suburban area, by average species concentrations and some quality features of their seasonal and diurnal variations. The obtained results confirmed the previously studied features of the daily variations of inorganic gaseous species in Moscow and showed such features for organic compounds in the countryside.

Within the program “Ecosystems of the Siberian Arctic Seas,” carried out by Shirshov Institute of Oceanology, Russian Academy of Sciences since 2007, studies of the water structure and spatial variability of the parameters of the carbonate system have been performed, and the intensity and direction of the carbon dioxide flux over the continental slope of the Laptev Sea and in the Vilkitsky Strait in September 2018 have been calculated. The presence of several main water masses that govern the water structure in the study area is shown. A strong spatial variability of the parameters of the carbonate system of seawater, determined by complexes of physical and chemical–biological processes, has been revealed. The intensity and direction of the carbon dioxide flux at the water–atmosphere boundary were calculated, which range from –12 to 4 mmol m–2 day–1. It was revealed that the investigated area of the outer shelf and continental slope of the Laptev Sea is an emitter of carbon dioxide into the atmosphere as of September 2018. Conversely, the area of the Vilkitsky Strait, is a CO2 sink zone.

Impact of climatically significant anthropogenic emissions to seasonal methane (CH4) variations observed at arctic and subarctic background stations in 1999 – 2019 has been quantitatively estimated using GEOS-Chem chemical transport model. It is shown that the formation of a stable continental pollution plume from sources in Western Europe, European Russia and Siberia allows to explain up to 5.5–8.6 % of observed CH4 surface concentration (~104–165 ppb). These atmospheric response values are several times higher than the of the observed annual methane variability amplitude (22–36 ppb), which allows to conclude that regional anthropogenic methane emissions sources play a significant role in regional CH4 balance in arctic and subarctic areas.