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This paper presents the results of a study of ground-level ozone concentration variability in Crimea at the background environmental monitoring station (BEMS) of the Karadag State Nature Reserve for 2012–2021 with a more detailed analysis of the last 6 years from 2016 to 2021. A significantly high level of air pollution by ground-level ozone in the observation area was revealed, despite the absence of significant sources of anthropogenic pollution in the vicinity of the station. The relationship between the ground-level ozone concentration and meteorological parameters has been studied, and characteristic wind directions leading to increased levels of ground-level ozone pollution have been established. Intra-annual variations are analyzed, and factors causing a local summer minimum of ground-level ozone concentration in individual years are identified. Using the NOAA HYSPLIT model and ERA5 reanalysis meteorological fields, a spatial analysis of the atmospheric circulation pattern in the region has been carried out. The recurrence of episodes in which the permissible 8-h average ozone concentration level of 100 μg/m3, as recommended by World Health Organization (WHO), was exceeded has been assessed, and the possible causes of these episodes are identified. Mechanisms of long-range transport and their contribution to the ozone regime in the station area have been established. Annual trends in ground-level ozone concentration between 2012 and 2021 are assessed as statistically insignificant. [ABSTRACT FROM AUTHOR]

Contributions of anthropogenic and wetland methane emissions in Northern Eurasia (>40° N) and Russia into the near-surface CH4 abundance are quantified using GEOS-chem global chemical transport model at ZOTTO, Teriberka, and Tiksi measurement sites. Numerical results agree well with the proposed semianalytical solution, in which the total contribution (atmospheric response) in the CH4 level at a given site is decomposed into direct (synoptic) and global terms. On an advection timescale corresponding to a synoptic time interval, the annual average direct contribution of Russian anthropogenic emissions into the CH4 mixing ratio measured at ZOTTO (38.6 ppbv) is more than twice as large as that for Western Europe sources (17.7 ppbv). For the Arctic sites, the anthropogenic inputs from Russian and European sources are roughly similar (19.5 and 12.4 ppbv, respectively). The input from continental sources into near-surface methane abundance and its annual variations at the Arctic sites are generally lower compared to those at the ZOTTO site due to larger transport times from upstream CH4 source regions. Model-based atmospheric responses in methane levels at the Teriberka and Tiksi sites to continental CH4 sources are found to be very close owing to the relatively homogeneous (circumpolar) spatial distributions of the anthropogenic and biogenic signals at high latitudes. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) total column (TC) measurements of the TROPOMI high-resolution orbital spectrometer have been validated by ground-based spectroscopic measurements at sites of the A.M. Obukhov Institute of Atmospheric Physics (OIAP), Russian Academy of Sciences, in Moscow and Zvenigorod for the period from June 28, 2018, to December 31, 2021. Correlation coefficients (R) between TROPOMI orbital data and ground-based stationary data are determined and analyzed. The high values of the correlation coefficient are obtained (R ~ 0.81–0.97) depending on the observation point, spatial averaging, and filtration applied. For different averaging of satellite data, the dependences of correlation parameters on the orbital angles, underlying surface albedo, and the height of atmospheric boundary layer are being investigated. No influence of albedo on the correlation parameters of orbital and ground-based measurements is found for both observation sites. No significant dependence of correlation parameters on the viewing zenith angle is detected either. However, the correlation coefficients depend on the viewing azimuth angles and the height of the atmospheric boundary layer. An increase in the correlation is obtained during observations at viewing azimuth angles of less than 40° (up to R ~ 0.97), as well as under an increase in the height of the atmospheric boundary layer (up to R ~ 0.90). [ABSTRACT FROM AUTHOR]

Results of measurements of the tropospheric and stratospheric NO2 columns with the TROPOMI (Tropospheric Monitoring Instrument) aboard the Copernicus Sentinel-5P satellite in 2018–2020 are compared with the results of ground-based measurements at the Zvenigorod Scientific Station (ZSS) of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The correspondence between the satellite and ground-based measurements is characterized by the difference between them, the linear correlation coefficients, and the regression coefficients. The dependences of these parameters on the season, cloud conditions, and the height of the atmospheric boundary layer are derived. [ABSTRACT FROM AUTHOR]

The results of new photometric () observations of the young star V719 Per from the IC 348 cluster are presented. Up until 2014, this star demonstrated brightness variability typical for UX Ori stars, i.e., caused by strong fluctuations in circumstellar extinction. In 2014, the star dimmed by approximately 3 magnitudes in the band and remained in that state until 2017. There is reason to believe that the eclipse was caused by a disturbance in the innermost regions of the star's protoplanetary disk. The dust raised above the disk caused the star's radiation to be blocked for approximately three years. The role of various processes in the generation of such disturbances is discussed. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1024856024330029 [ABSTRACT FROM AUTHOR]