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The processes of planetary wave breaking (Rossby Wave Breaking – RWB) significantly contribute to variability in stratospheric circulation. Employing a previously developed method for identifying RWB, adapted for stratospheric circulation, this study analyzes the climatology and long-term variability of RWB processes in the middle stratosphere. The method is based on the analysis of potential vorticity (PV) contour geometry at the 850-K level using ERA5 data within the PV range 0–400 PVU (Potential Vorticity Units) determined based on PV field climatology. It was demonstrated that RWB processes exhibit intraseasonal peculiarities. Most frequently, waves break in the northern regions of East Asia and the Pacific Ocean from October to December and in April to March. In January and February, no areas with prevailing RWB processes were identified. We obtained a statistically significant increase in the number of RWB for the first half of winter (October–December) and for the end of the winter period (March and April). For midwinter (January and February), insignificant negative trends were obtained. The results of this work can be used to analyze the long-term variations in stratospheric circulation and, in particular, the occurrence of stratospheric anomalies preceding sudden stratospheric warmings.

The changes in the response of air temperature to the variations in the instantaneous blocking frequency (IBF) ( ) between the periods 1979–1999 and 2000–2020 are studied. Blocking patterns, which are the spatial distributions of the coefficients of correlation between the IBF and the 1000 hPa temperature field, are used as the main characteristic. The blocking frequency is calculated in ten longitudinal sectors in the eastern direction from the west of the North Atlantic region to the eastern borders of Siberia and the Pacific Ocean. It is found that blocking patterns moved northward over the Atlantic region (November, December, and February), the Ural region and Siberia (November, January, and February) in 2000–2020. In addition, they were characterized by more pronounced areas of negative correlations over Eurasia and North America as compared to 1979–1999. Along with the pronounced correlation pattern of the Atlantic region, the patterns of the Ural region and Western Siberia (U-WS) proved to be the most significant. It is assumed that the IBF variability over the U-WS sector is an important indicator of the development of the most significant blocking processes over Eurasia in terms of the temperature regime anomalies. The influence of U-WS blockings was the least noticeable in 2000–2020 for December and in 1979–1999 for January, when the response of the temperature field to the blocking changes was similar to the response of the negative phase of the North Atlantic Oscillation.

Сlimate warming in the Arctic is several times faster than in other regions of the globe. This сan be the result of strengthening of feedbacks between climate and atmospheric composition. However, there are very few data on changes in the concentration of climatically active substances in this region. Therefore, to fill the gap in data on the vertical distribution of gas and aerosol composition of air over the Russian Arctic, an airborne survey of the atmosphere and water surface over all the Russian Arctic Ocean seas was performed with use of the Tu-134 Optik aircraft laboratory in September 2020. This paper analyzes the spatial distribution of gas and aerosol composition in the Arctic troposphere. It is shown that during the experiment, the CO 2 mixing ratio increased in the near-water and boundary layers and decreased in the free troposphere from west to east. The methane content in the near-water layer decreased in the same direction. Concentrations of CO, NO X , and SO 2 in the Russian Arctic were very low, which was typical for remote background areas. All aerosol fractions also showed a decrease in their content from west to east.

The ongoing global warming leads to the need in continuous monitoring of greenhouse gas concentrations and the magnitude of their fluxes. Gas exchange between terrestrial ecosystems and the atmosphere is mainly measured using eddy covariance, gradient, and chamber methods. This work compares greenhouse gas fluxes measured using the eddy covariance technique onboard an aircraft laboratory and with the gas analysis system and meteorological sensors at ZOTTO observatory. Instrument suites of the aircraft laboratory and the observatory are described. The comparison results showed that CO2 and CH4 fluxes measured by two different methods at the same altitudes coincide in sign, are close to each other in the value for carbon dioxide, and differ by up to 2 times for methane. The results are of interest to specialists who study greenhouse gas fluxes using the eddy covariance method.

Methane is an important greenhouse gas, and its atmospheric concentration has nearly tripled since pre-industrial times. This paper presents estimates of the strength of two primary sources of methane emissions in Western Siberia: wetlands emissions (WEs) and methane emissions from biomass burning (BBEs). The atmospheric circulation data used are from ECMWF Era-Interim, BBE - GFED (Global Fire Emissions Database) and CAMS GFAS (Global Fire Assimilation System), WE - MACC-III greenhouse gases inversions, v10_an. We have revealed that the highest BBE in Western Siberia (summer periods of 2005, 2006, 2007, 2010, 2011, 2012, and 2013) are accompanied by blocking in the atmosphere. We have also showed that there is a lag of 3-6 days between the beginning of the blocking and the periods of maximum BBE. Features of Rossby wave dynamics and blocking highs and ridges are examined as a possible reason for the lag. It turned out that the maximum BBE is commonly observed when a blocking high (or ridge) is shifted from Western to Eastern Siberia. The GFAS data demonstrate higher BBE than GFED (except for 2010). According to GFED, the average emission for all years is only 14.2% from WEs (the maximum emission is 35% (2012), and the minimum one, 2.2% (2007) from WEs). According to GFAS, the average emission for all years is 38.1% from WEs (the maximum emission is 127,4% (2012), and the minimum one, 6.1 (2010) % from WEs).

The correlation of precipitation anomalies over Eurasia with atmospheric blocking events was examined with ERA Interim reanalysis data. We found that, regardless of the frequency of the atmospheric blocking events, they significantly affect the distribution of rainfall over all Eurasian regions in summer, due to both the change in the westerly transport and the dominant dipole blocking structure. It is important that, depending on the blocking positions in Asia, there are heavy rainfalls in an arid zone which includes Kazakhstan, Mongolia, Northern China, and the Trans-Baikal Territory.

We investigate the relationship between Eurasian blocking and summer precipitation in the basin of the Selenga River (Lake Baikal's main tributary) in order to find the reasons of current low-water period in the Lake Baikal basin. In this paper, we study the development of blocking events over Europe and the Russian Far East (RFE) and anomalies in precipitation over the Selenga river basin. Blocking over Europe and the Russian Far East contribute to arid conditions over the southern (Mongolian) part of the Selenga basin and precipitation over the northern (Russian) part of the basin. We show that from 1979 to 2017 there were 10 years with joint blocking events over Europe and RFE in July: 1980, 1981, 1983, 1991, 1999, 2001, 2003, 2010, 2011 and 2014. Months with normal and higher than normal total precipitation in the basin were observed in 1983, 1991, and 2003. Months with lower precipitation were in 1980, 1981, 1999, 2001, 2010, 2011, and 2014. We conclude that simultaneous development of blocking over Europe and RFE for at least three days, along with intensity, duration and localization of blocking are important factors to form conditions favorable for intense precipitation over the northern part of the Selenga basin.

This paper studies the long-term variability of frequency of atmospheric blockings over Western Siberia in 1948–2015 based on the data of three reanalysis projects. We revealed a decreasing blocking frequency for eight of twelve months. However, since the estimated trends of blocking frequency are small comparing to the significant amplitude of interannual variations, we proposed to divide the entire studied period into several quasi-decadal intervals that differ both in the amplitude of interannual fluctuations of blocking frequency and in trends. The effect of Western Siberian blockings imposed on synoptic and climatic variability of meteorological parameters in Asia was studied. The study demonstrated that in summer teleconnection patterns in temperature and precipitation fields are of the close sign-alternating structure; this indirectly indicates that in Western Siberia the blocking is a part of a large-scale wave mechanism. Like the Ural blockings, the blockings occurring over Western Siberia affect meteorological characteristics within the East Asian monsoon area. In winter time they contribute to lower surface temperature and decreased precipitation in Southeast Asia. In summer during blocking events over Western Siberia, precipitation increases in the East Asian monsoon area.

This paper presents results of a comprehensive analysis of the formation of gases and aerosol composition during the anomalously hot April 2020 in Western Siberia. The analysis of the observed change in atmospheric composition and a modeling study with the WRF-Chem is carried out for suburban (TOR-station) and background (FON-station) areas. Two episodes of increased gases and aerosols were detected:13-15 April with a peak on 14 (in most part for the TOR station: increased NO, NO2, CO, CO2, aerosols) and 17-24 April with a peak on 23 (for both stations O3, aerosol, in most part for the FON station: NO2, SO2, CO, and CO2). Atmospheric circulation in the first episode was characterized by mesoscale differences between the two studied locations (surface temperature delta, although both stations are in the same region of large-scale transfers). For the second episode, a large scale atmospheric ridge was observed, which caused a transboundary transfer from Northern Kazakhstan and early wildfires. The simulation with WRF has demonstrated in most cases only the role of wildfires and, in general, has not demonstrated any observed differences between the two episodes. It shows that there is a need to search for more sensitive methods of discovering sources of pollution.

This paper presents preliminary results of the effectiveness analysis of an air quality forecasting system for the city of Novosibirsk with replenishment of the missing information on emission sources by solving an inverse problem with urban monitoring network data. In solving the inverse problem, a priori information about the location and mode of the sources is used. To simulate concentration distributions, the WRF-Chem model is used, and a simplified model of chemical transport is applied to solving the inverse problem. These models are offline coupled in a hybrid forecast system in order to improve the initial information about the spatial distribution of emission intensity and air quality forecast, respectively. The results of numerical experiments and their analysis are presented. The influence of an urban parameterization on the results of the forecast is shown.