Zvenigorod Scientific Station Research Articles

Validation of TROPOMI Satellite Measurements of the NO2 Content in the Troposphere and Stratosphere with Ground-Based Measurements at the Zvenigorod Scientific Station of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Validation of TROPOMI Satellite Measurements of the NO2 Content in the Troposphere and Stratosphere with Ground-Based Measurements at the Zvenigorod Scientific Station of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Validation of results of measurements of the NO<sub>2</sub> contents in the troposphere and stratosphere with the TROPOMI satellite instrument on the basis of ground-based measurements at the Zvenigorod scientific station of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Validation of results of measurements of the NO<sub>2</sub> contents in the troposphere and stratosphere with the TROPOMI satellite instrument on the basis of ground-based measurements at the Zvenigorod scientific station of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Columnar and surface urban aerosol in the Moscow megacity according to measurements and simulations with the COSMO-ART model

Abstract. Urban aerosol pollution was analyzed over the Moscow megacity region using the COSMO-ART (COSMO – COnsortium for Small-scale MOdelling, ART – Aerosols and Reactive Trace gases) online coupled mesoscale model system and intensive measurement campaigns at the Moscow State University Meteorological Observatory (MSU MO, 55.707∘ N, 37.522∘ E) during the April–May period in 2018 and 2019. We analyzed mass concentrations of particulate matter with diameters smaller than 10 µm (PM10), black carbon (BC) and aerosol gas precursors (NOx, SO2, CHx) as well as columnar aerosol parameters for fine and coarse modes together with different meteorological parameters, including an index characterizing the intensity of particle dispersion (IPD). Both model and experimental datasets have shown a statistically significant linear correlation of BC with NO2 and PM10 mass concentrations, which indicates mostly common sources of emissions of these substances. There was a pronounced increase in the BC/PM10 ratio from 0.7 % to 5.9 %, with the decrease in the IPD index related to the amplification of the atmospheric stratification. We also found an inverse dependence between the BC/PM10 ratio and columnar single-scattering albedo (SSA) for the intense air mixing conditions. This dependence together with the obtained negative correlation between wind speed and BC/PM10 may serve as an indicator of changes in the absorbing properties of the atmosphere due to meteorological factors. On average, the relatively low BC / PM10 ratio (for urban regions) of 4.7 % is the cause of the observed relatively high SSA = 0.94 in Moscow. Using long-term parallel aerosol optical depth (AOD) measurements over the 2006–2020 period at the MSU MO and under upwind clean background conditions at Zvenigorod Scientific Station (ZSS) of the IAP RAS (55.7∘ N, 36.8∘ E), we estimated the urban component of AOD (AODurb) and some other parameters as the differences at these sites. The annual mean AODurb at 550 nm was about 0.021 with more than 85 % of the fine aerosol mode. The comparisons between AODurb obtained from the model and measurements during this experiment have revealed a similar level of aerosol pollution of about AODurb=0.015–0.019, which comprised 15 %–19 % of the total AOD at 550 nm. The urban component of PM10 (PM10urb) was about 16 µg m−3 according to the measurements and 6 µg m−3 according to the COSMO-ART simulations. We obtained a pronounced diurnal cycle of PM10urb and urban BC (BCurb) as well as their strong correlation with the IPDs. With the IPD index change from 3 to 1 at night, there was about a 4 times increase in PM10urb (up to 30–40 µg m−3) and a 3 times increase in BCurb (up to 3–3.5 µg m−3). At the same time, no pronounced daily cycle was found for the columnar urban aerosol component (AODurb), although there was a slight increase in model AODurb at night.

Three decades of remote sensing of NO2 vertical distribution and column content at the A. M. Obukhov Institute of Atmospheric Physics

The paper reviews the results of 30-year spectrometric measurements of vertical distribution and column content of NO2 at the Zvenigorod Scientific Station (ZSS) of the A. M. Obukhov Institute of Atmospheric Physics and presents analysis of NO2 long-term trends and interannual variations. The station is located in the western Moscow region. It is part of the Network for the Detection of Atmospheric Composition Change (NDACC). Measurements are done in the morning and evening twilight by zenith-scattered visible solar radiation. Vertical NO2 profiles are retrieved and column NO2 contents are calculated by profile integration. Long term trends and inter-annual variations of NO2 are analysed by multivariate regression method taking into account autocorrelation of data in a wide range of time scales. Seasonally dependent estimates of NO2 trends and interannual variations due to the quasi-biennial oscillation, El Nino–Southern oscillation, North Atlantic Oscillation, and the 11-year solar cycle are obtained. Most pronounced (in per cent units) trends and circulation and solar cycle effects are peculiar to the winter–spring period of the year. Mutual influence is assessed between the estimates of the trend and the solar cycle effect in stratospheric NO2.

Submicron aerosol and nitrogen dioxide in the atmospheric near-surface layer at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics RAS: Thirty years of measurements

The paper presents results of measurements and trend analysis of the mass concentration of submicron aerosol and the NO2 content in the atmospheric surface layer at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The station is located in a rural area of the western Moscow region. Aerosol concentration is determined by directional light scattering in a flow nephelometer. The NO2 content is measured spectrometrically by zenith-scattered solar radiation. Three decades of aerosol and NO2 measurements give a possibility to analyze long-term trends in near-surface aerosol and NO2. Seasonally dependent estimates of the aerosol trends are presented for three periods differing in character of aerosol variability: 1991–2002, 2003–2012, and 2013–2020. The common feature of the trends is a general decrease in the aerosol concentration. There are however significant interdecadal differences in the strength of the trends and in their seasonal dependence. The NO2 content in the near-surface layer undergoes a significant positive trend. The NO2 increase is likely associated with an increase in the population and human activity resulting, in particular, in the increase in motor traffic in the region. Effects of wind direction on aerosol and NO2 anomalies are also studied.

Long-Term Tendencies of Carbon Monoxide in the Atmosphere of the Moscow Megapolis

This paper presents the results of a comprehensive analysis of measurements of CO total content (CO TC) at stations of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), in Moscow and Moscow oblast. Also CO in-situ data obtained from automated stations of the Mosecomonitoring network, satellite monitoring results and information on the parameters of the atmospheric boundary layer in Moscow and the surrounding regions are analyzed. The long-term variability of CO TC and meteorological parameters is investigated, the carbon monoxide accumulation characteristics in calm days in the atmospheric boundary layer are obtained. A decrease in the average annual values ​​of TC CO in 2000–2018 was found in Moscow (–2.56 ± 0.52%/year) and at the Zvenigorod Scientific Station (ZSS) (‒1.15 ± 0.37%/year). However, the rate of decrease in both sites is different in different seasons and periods. After about 2007–2008, the rate of CO TC reduction decreased at both sites. In 2008–2018, at the ZSS, an increase in CO TC was recorded in the summer and autumn months at a rate of about 0.7%/year. An increase in the wind speed in the atmospheric boundary layer of Moscow in different periods of 2000–2018 at a rate of 0.4–1.6%/year has been determined. At the same time, no statistically significant changes in wind speed were found in Kaluga oblast. The recurrence of calm days in Moscow in 2006–2017 decreased (–7.06 ± 3.96%/year) with a decrease in the anthropogenic part of the CO content in the same period (–6.72 ± 3.48%/year). The results indicate the influence of the climatic (meteorological) factor on air quality in Moscow.

Changes in the Column Content and Vertical Distribution of NO2 According to the Results of 30-Year Measurements at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Changes in the Column Content and Vertical Distribution of NO2 According to the Results of 30-Year Measurements at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences

Long-term trends in the mass concentration of near-surface aerosol at Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics RAS from 1991-2019 measurements

Estimates of seasonally dependent trends in the mass concentration of the near-surface aerosol are presented on the base of results of 29-year measurements at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of atmospheric physics. The station is located in the woody countryside, 50 km west to Moscow. The multiple regression method is used for the analysis, in which autocorrelation of measurement data on large time scales is taken into account. Two periods are considered: 1991-2002 and 2013-2019. Excluded is the period 2003-2012 when abnormally high aerosol concentrations of unknown origin were often observed. For the periods 1991-2002 and 2013-2018, statistically significant negative trends were obtained for spring and summer seasons, respectively, and for the entire year. The spring trend in logarithm of concentration in 1991-2002 was -2.6% per year, and the annual trend was about -0.7% per year. For 2013-2019 a strong negative trend of about -6% per year was obtained in the summer season, and the annual trend estimate was -2.3% per year. The probable cause of the negative aerosol trend in the spring seasons of 1991-2002 is long-term changes in atmospheric transport. The negative trend in the summer seasons of 2013-2019 is probably due to the negative trend of summer temperature, drying and felling of spruce forest.

Comparison of measured and simulated NO2 integral content in the lower troposphere in Moscow region

We presented preliminary results of a comparison of the NO2 integral contents (IC) measured by the DOAS technique and simulated by the COSMO-Ru7-ART chemical transport model at Zvenigorod Scientific Station (ZSS) located in 38 km west from Moscow. The comparison covers January and July of 2014 when background and polluted by Moscow air masses were observed at ZSS. The measured NO2 IC in the atmospheric boundary layer observed at ZSS does not exceed 0.5 × 1016 molec × cm−2 in background conditions of the atmosphere when non-east wind direction dominated. It grows up to 5.4 × 1016 molec × cm−2 when polluted air masses come from Moscow megacity. Simulated NO2 IC has similar behaviour. As a whole, a good agreement between measured and simulated datasets is observed. Some overestimation of the NO2 emission presents for sources located to the south and north-east from ZSS. Underestimation of the NO2 emission presents for sources located inside of Moscow megacity and located to south-west from ZSS.

Observations of Integral Formaldehyde Content in the Lower Troposphere in Urban Agglomerations of Moscow and Tomsk Using the Method of Differential Optical Absorption Spectroscopy

Regular measurements of the integral formaldehyde content (IFC) in the lower troposphere have been carried out in the impact area of the Moscow urban agglomeration (Zvenigorod Scientific Station, ZSS) and in the southeastern part of Tomsk (Siberian Lidar Station, SLS) since 2009. The paper briefly describes the instrumentation and measurement techniques used and presents the first results of the measurements. The average level of the formaldehyde content at ZSS is shown to exceed that in Tomsk. The most probable cause of increased formaldehyde content during the easterly winds at ZSS is due to the arrival of polluted Moscow air. The observations in Tomsk suggest that the possible influence of polluted urban air on the formaldehyde content begins to show up at temperatures above 25°С. The positive IFC dependence on the air temperature was revealed at both stations.

Study of transport of atmospheric admixtures and temperature anomalies using trajectory methods at the A.M. Obukhov Institute of Atmospheric Physics

Based on the trajectory model NOAA HYSPLIT_4 and reanalysis NCEP/NCAR a method for calculating extra large sets (millions of trajectories) of forward and backward trajectories has developed in A. M. Obukhov Institute of Atmospheric Physics (OIAP) of RAS. Using the arrays and trajectory methods, the fields of potential sources of aerosol and gas species are identified. Analyzed are distributions of potential regions of sources of ammonium nitrate, ammonium sulfate, and silicate contributing the surface aerosol, as well as of tropospheric formaldehyde and stratospheric nitrogen dioxide at the Zvenigorod Scientific Station of OIAP, of stratospheric ozone at the Kislovodsk High Mountain scientific Station of OIAP, of column aerosol contents at AERONET stations of Tomsk and Ussuriysk. The method is also applied to identification of remote regions associated with anomalies of winter surface air temperature in Moscow and anomalies of precipitation in the Lake Baikal basin.

Radiative and Thermal Impacts of Smoke Aerosol Longwave Absorption during Fires in the Moscow Region in Summer 2010

The aerosol longwave radiative forcing of the atmosphere and heating rate of the near-surface aerosol layer are estimated for the extreme smoke conditions in the Moscow region in summer 2010. Thermal radiation fluxes in the atmosphere are determined using the integral transmission function and semiempirical aerosol model developed on the basis of standard aerosol models and measurements at the Zvenigorod Scientific Station, Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The aerosol radiative forcing reached 33 W/m2 at the lower atmospheric boundary and ranged between–1.0 and 1.0 W/m2 at the upper atmospheric boundary. The heating rate of the 10-m atmospheric layer near surface was up to 0.2 K/h during the maximum smoke conditions on August 7–9. The sensitivity of the aerosol longwave radiative forcing to the changes in the aerosol absorption coefficient and aerosol optical thickness are estimated.

Study of trends of total CO and CH4 contents over Eurasia through analysis of ground-based and satellite spectroscopic measurements

Trends of total CO and CH4 contents are estimated from satellite AIRS spectrometer data for the Eurasian domain (0–180° E, 0–85° N) for different time periods and seasons. The results are compared with similar estimates, obtained from ground-based spectroscopic measurements at seven stations of the European Network for the Detection of Atmospheric Composition Change (NDACC) and at measurement sites of the Institute of Atmospheric Physics, Russian Academy of Sciences (Zvenigorod Scientific Station (ZSS), Zotto, and Beijing) and St. Petersburg University (Peterhof), located in the study domain. Overall, the total CO decreased over northern Eurasia during the period of 2003–2015 at a rate of 0.05–1.5%/yr, depending on the region; while the total CH4 increased at a rate of 0.16–0.65%/yr. Since 2007, the total CO has been increased during summer and autumn months in most mid- and high-latitude Eurasian background regions, and the total CH4 growth has been accelerated. Changes in the global photochemical system, proceeding against the background of global climate change and, in particular, changes in the “sources/sinks” ratio for minor atmospheric admixtures are suggested as possible causes of this dynamic of trends of the atmospheric CO and CH4 contents.

Changes of cooling near mesopause under global warming from observations and model simulations

The results of joint analysis of temperature variations near mesopause from long-term measurements at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics RAS in 1960–2015 and variations of surface air temperature characterizing global climate change. Together with variations of temperature at the mesopause T ms from measurements of the hydroxyl emissions we analyzed the temperature variations near mesopause T m reduced to the same level of solar activity. The observed strong decrease in temperature near mesopause during last decades, particularly in winter, with its tendency to slow down since the 1980’s is was detected against the background of general increase in the surface air temperature of the Northern Hemisphere T NHs and the Earth as a whole. It was revealed a sharp drop in winter temperature near mesopause in 1970s. and its synchronicity with the shift in climatic features at the surface associated with changes in formation of El Nino events and their impact on the global climate. The general significant negative correlation of temperature variations near mesopause and T NHs detected from 56-year observational data was not accompanied by any significant coherence between the most long-period temperature variations from the cross-wavelet analysis. To assess the possible manifestation of this coherence the results of numerical simulations with a global climate model were used. According to model simulations for the 20–21 centuries taking into account anthropogenic forcings for significant coherence between long-term variations T m and T NHs the prolonged observations are required for temperature near mesopause–about a century or more.

Source regions of ammonium nitrate, ammonium sulfate, and natural silicates in the surface aerosols of Moscow oblast

Maps of potential source regions of ammonium nitrate, ammonium sulfate, and natural silicates in the surface aerosols in 2002–2005, 2010, and 2012–2015 are obtained based on measurements of the optical depth of 1–2 μm surface aerosol samples and the analysis results of backward trajectories of air parcels at the Zvenigorod scientific station (ZSS) of the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The most likely potential source regions of ammonium nitrate are in western and central Europe; those of ammonium sulfate are in southern Ukraine, southern Russia, and northwest Kazakhstan; and those of natural silicates are in the Caspian and Aral regions. The maps of potential source regions are consistent with EMEP fields of surface concentrations of nitrates and sulfates and natural aerosol concentration in PM2.5.

Total content of carbon monoxide in the atmosphere over Russian regions according to satellite data

Carbon monoxide (CO) total columns over European Russia (ER) and western Siberia (WS) have been analyzed using MOPITT (V5, TIR/NIR, L3) IR-radiometer data obtained in 2000–2014. High CO contents are revealed over large urban and industrial agglomerations and over regions of oil-and-gas production. A stable local CO maximum is observed over the Moscow agglomeration. Statistical characteristics of CO total columns observed in the atmosphere over ER and WS in 2000–2014 are presented. An analysis of long-term changes in CO content reveals nonlinear changes in the CO total column over northern Eurasia in 2000–2014. Results of a comparative analysis of annual variations in atmospheric CO contents over ER and WS are given. Based on Fourier analysis, empirical models of annual variations in total CO contents over ER and WS are proposed. Relations between regional CO contents and fire characteristics and between spatial CO distributions and features of large-scale atmospheric dynamics under conditions of weather and climate anomalies in the summers of 2010 in ER and 2012 in WS are analyzed. Data on total CO contents measured with a MOPITT satellite radiometer and a ground-based spectrometer operating at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics are compared.

The regular nocturnal course of temperature in the midlatitude mesopause region according to hydroxyl airglow measurements

Using ground-based spectral measurements in the near-infrared range at the Zvenigorod scientific station of the Institute of Atmospheric Physics (56° N, 37° E) for 2000–2013, we obtained average nighttime changes in rotational and vibrational temperatures of hydroxyl with its emission layer localized at mesopause heights. The rotational temperature reflects the kinetic temperature of the emission layer of the atmosphere. The analysis made it possible to determine the characteristics of the first three harmonics of diurnal temperature dynamics in the mesopause region both with and without altitudinal oscillations of the OH emission layer. In both cases, the second and third harmonics are statistically significant: their amplitudes are ∼1 K and the phases of their first maxima are near 0300 and 0130 local solar time.

On the nature of long-period variations in mass concentration of near-ground aerosol

Variations in the aerosol concentration with periods more than one month are analyzed using measurements of mass concentration of the near-ground aerosol at Zvenigorod Scientific Station of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. It is shown that the variations can be associated with the periodic recurrences of atmospheric transport trajectories from certain directions. We considered the cases when long-period variations in aerosol concentration were due to episodes of increased or decreased concentrations caused by aerosol advection from the corresponding directions. In particular, the 1.5-month variations in the aerosol mass concentration in 1995 were found to be due to the 1.5-month recurrences of the concentration maxima caused by southeasterly transport. The three-month periodicity of the transport episodes from directions of Baltic and North Atlantic in 2004 manifested themselves in 3-month recurrence of the aerosol concentration minima. A statistical relation is revealed between the near-ground aerosol concentration and the Arctic upper troposphere dynamics.

Winter–spring anomalies in the stratospheric content of NO2 from ground-based measurement results

According to the results of ground-based spectrometric measurements, significant negative anomalies in the stratospheric content of NO2 were observed at a number of stations in the Northern Hemisphere during winter and spring 2011. These anomalies were accompanied by those in total ozone content (TOC) and stratospheric temperature and were caused by the transport of air masses from the region of the arctic ozone hole. The results of analysis of vertical NO2 profiles obtained at the Zvenigorod Scientific Station showed that a certain contribution to the 2011 negative anomalies of NO2 was made due to a denitrification of the polar stratosphere in the ozone-hole region. The relation between variations in the total content of NO2 and those in the TOC and temperature was analyzed for both the Northern and Southern hemispheres during winter–spring periods. It was found that this relation depends on the phase of the quasi-biennial oscillation in the stratospheric equatorial wind. Such a correlation usually intensifies if only the episodes of negative anomalies caused by the transport of stratospheric air masses from the ozone-hole region are taken into consideration.

Internal gravity-shear waves in the atmospheric boundary layer from acoustic remote sensing data

The year-round continuous remote sounding of the atmospheric boundary layer (ABL) by means of the Doppler acoustic radar (sodar) LATAN-3 has been performed at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, since 2008. A visual analysis of sodar echograms for four years revealed a large number of wavelike patterns in the intensity field of a scattered sound signal. Similar patterns were occasionally identified before in sodar, radar, and lidar sounding data. These patterns in the form of quasi-periodic inclined stripes, or cat’s eyes, arise under stable stratification and significant vertical wind shears and result from the loss of the dynamic stability of the flow. In the foreign literature, these patterns, which we call internal gravity-shear waves, are often associated with Kelvin-Helmholtz waves. In the present paper, sodar echograms are classified according to the presence or absence of wavelike patterns, and a statistical analysis of the frequency of their occurrence by the year and season was performed. A relationship between the occurrence of the patterns and wind shear and between the wave length and amplitude was investigated. The criteria for the identification of gravity-shear waves, meteorological conditions of their excitation, and issues related to their observations were discussed.