A. V. Dzhola

Variations of carbon monoxide density in the total atmospheric column over Russia between 1970 and 1995: Upward trend and disturbances, attributed to the influence of volcanic aerosols and forest fires

The analysis of total column spectroscopic CO observations over Russia revealed an upward lin- ear trend between 1970 and 1995 with a rate of about 1.0 ppbv/year or 0.96 %/year. A similar trend was re- ported earlier for the CO total column over Switzer- land between 1950 and 1987. This rate is almost 3 times higher, than the rate of CO increase between 1920 and 1950, obtained from ice core data. Main distur- bances of CO tropospheric concentration coincided with vast wildfires in the central Russia in 1972 and volcanic eruptions. Stratospheric volcanic aerosol probably in- fluence the concentration of tropospheric OH radicals, which destroy CO molecules. The aerosol scatters pho- tochemically active UV radiation and, in the same time, triggers the stratospheric ozone photochemical destruc- tion. Diminished total column ozone UV absorption can offset the increase of UV scattering due to addi- tional aerosol. Studying these processes is important for a prediction of further CO and OH long-term vari- ations in the global atmosphere.

Variations of the total content of carbon monoxide over Moscow megapolis

The results of the carbon monoxide total content measurements over Moscow and Zvenigorod for 2005–2008 are compared with the same data sets for Moscow 1986–2005 and Beijing, 1992–2007. Two identical medium resolution diffraction spectrometers (resolution 0.2 cm−1) with solar tracking system were used. The CO total content measured simultaneously over the city and over Zvenigorod Scientific Station (ZSS) of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (60 km west from Moscow). This method allows to isolate an urban part of CO content. The acoustic locator SODAR LATAN-3 measurements permitted us to study the influence of the carbon monoxide ventilation conditions upon level of pollution. Correlation coefficients between the urban part of CO content and average wind speed for cold and warm seasons were obtained. The data sets analysis showed a preeminent effect of the wind within boundary layer (up to 300 m) over the CO ventilation. The urban part of the CO content hasn’t increased in spite of more than quintuple increase of the motor-vehicles number in Moscow. An increase of the rural CO total column for the 1970–1985 has transformed into its virtually stable amount in between of 1986 to 2000, changed then to a decrease for 2001–2008. We noted the 2008 as “the year of the CO total column minimum” over the past decade. The effect of urban CO sources influence on the CO total column in rural area is small, i.e. on a level of 3% of the total number of measurements. The number of extremal daily values for Moscow is estimated as 5%, and 20% for Beijing.

Carbon monoxide and total ozone in Arctic and Antarctic regions: seasonal variations, long-term trends and relationships

Total column abundances of carbon monoxide (CO) were measured in Zvenigorod, near Moscow, and in the Russian Arctic (from Severnaya Zemlya to Wrangel Island, including the drifting station in the central part of the Arctic Basin). CO was found to decrease from early spring to summer, both in central Russia and in the Arctic; absolute mean CO abundances in both regions differed little. Vertically averaged CO mixing ratios over Zvenigorod were compared with those measured in the surface layer at Point Barrow, Alaska, between July 1988 and December 1990. Good agreement between them was observed in summer; in winter and early spring, however, the CO mixing ratios for Barrow were 40% greater than for Zvenigorod. This difference is most likely explained by CO becoming concentrated under the Arctic inversion layer in winter. The mean tropospheric mixing ratio over Zvenigorod increased at a rate of 0.7 ± 0.2% year−1 during the period between 1970 and 1993. This increase was not steady; during 1970–1982 it was larger, ∼ 1.5% year−1. Long-term variations in both sources and sinks of CO could be responsible for these phenomena.

First measurements of formaldehyde integral content in the atmosphere using MAX-DOAS in the Moscow region

We present the first observations of formaldehyde (HCHO) atmospheric column performed for Zvenigorod, Moscow region, Russia. The data were retrieved from UV spectra of the scattered solar radiation measured by the multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument developed by the Japan Agency for Marine-Earth Science and Technology. We developed an algorithm for the HCHO retrieval from these spectra. For retrieval of the HCHO differential slant column densities, we used the DOAS settings used as baseline in the Cabauw Intercomparison Campaign of Nitrogen Dioxide Measuring Instruments (CINDI). The slant column densities of HCHO were converted to vertical column densities (VCDs) using the air mass factors calculated by a radiative transfer model. The determination of HCHO in the reference spectrum used multi-axis measurements. The variability of the HCHO vertical column in 2010 is analysed. The HCHO vertical column density is larger during east wind directions than during non-east wind directions. This can be associated with the Moscow Megacity influence on air quality at Zvenigorod. The estimation of the Moscow Megacity influence on HCHO abundance at Zvenigorod is around 2.5 × 1014 molec cm−2 per 1 km length of trajectory path inside the Moscow Ring Road. A temperature effect is noticeable in the HCHO VCD. Our data show a statistically significant positive temperature effect in HCHO for the background condition for temperatures from −5°C to +33°C. The temperature trend in HCHO data at Zvenigorod Scientific Station is about (8.9 ± 2.3) × 1014 molec cm−2 (°C)−1. The increase of the HCHO VCD during increase of the air temperature can be explained by the HCHO formation from non-methane biogenic volatile organic compounds (e.g. isoprene) for which more emission is expected at higher temperatures, and by growth of areas of forest and turf fires.

Determination of carbon monoxide pollution of the atmosphere over Moscow with a spectroscopic method

The results of measurements of the total content of carbon monoxide in an atmospheric column over Moscow and the Zvenigorod Scientific Station (ZSS) are given for the period 1993–2005. The simultaneous measurements of the regional background contents of carbon monoxide over a rural area (ZSS) and over Moscow made it possible to isolate an urban portion of the CO content. The total content of CO over the city varies significantly from day to day from values close to the background value to values that are 2.5–3 times greater than the background value. The number of days with such a CO content is 5% of the total number of measurement days. Such a CO content is most often observed during the cold seasons. During the warm seasons, in most of the cases, slight excesses of the CO background value are observed in the urban atmosphere. Variations in the CO content are determined mainly by wind-velocity variations and temperature inversions. In 2002, the high CO concentrations were due to forest and peatbog fires. On some days, over the ZSS, the concentrations of CO were high as never before. Over this period (12 years), the CO content in the surface air layer over the city did not increase.

Studying the pollution of Moscow and Beijing atmospheres with carbon monoxide and aerosol

The measurements of submicron aerosol and black carbon (BC) surface concentrations, and carbon monoxide (CO) total column in 1992–2012 in Beijing and Moscow are illustrated. The specific features in the long-term variations in the studied impurities in these megacities are discussed. The level of pollution with all three impurities in Beijing is substantially higher than in Moscow. From 1992 to 1999, the monthly means of black carbon and aerosol increased in Beijing. These concentrations substantially decreased beginning from 2000. From 2007 to 2011, black carbon decreased and submicron aerosol increased. In 1996–2003 the urban part of CO total column (TC) in Beijing was on average higher than in 2006–2012 by a factor of 1.4. The anthropogenic part of CO in Moscow decreased in 2006–2012. High aerosol and CO concentrations, comparable with concentrations rather typical of Beijing, were observed in Moscow only during wildfires in 2010. Using the cluster analysis statistical methods, it has been indicated that the main sources of the air pollution in Beijing are located 100–500 km southward.

Variations of the carbon monoxide total column and parameters of the atmospheric boundary layer in the center of Moscow

The content of carbon monoxide in the atmosphere over Moscow has been measured from the absorption spectra of solar radiation in the infrared spectral range (2153–2160 cm−1) for the period 1993–2007. A main advantage of the method is a virtual independence of the results averaged over a significant space and atmospheric thickness on local and even relatively large-scale pollution sources. Moreover, the method permits the determination of the characteristics of anthropogenic pollution of the city air by CO by comparison of the measurement of CO content in two observation sites (one is in the city center and another is outside the city). In both the cases, diffraction spectrometers with the resolution 0.2 cm−1 supplied with a sun tracking system were used. From 2005, in the center of Moscow, the parameters of the atmospheric surface layer have continuously been measured using a LATAN-3 acoustic locator. The measurements show that in this period (14 years), the CO content within an air layer polluted by the city did not increase in spite of the threefold increase in the number of automobiles in the city. Thus, the method allows one to determine the trend of air pollution above Moscow. Variations of the CO content are mainly determined by the wind velocity and the presence of temperature inversions. Using the results of the acoustic sounding, a relation between the pollution magnitude and the condition of the impurities has been elucidated. The wind velocity in the surface (to 500 m) layer has the greatest effect on the pollution accumulation in the city atmosphere. For cold and warm seasons, the correlation coefficients of the urban proportion of the CO content with the wind velocity averaged over air layers of various heights are found.

Variation Trend and Characteristics of Anthropogenic CO Column Content in the Atmosphere over Beijing and Moscow

Abstract The anthropogenic CO column content in the atmosphere is derived from measurements with infrared grating spectrometers in Beijing, China, and Moscow, Russia, during 1992–2012. Some specific variation characteristics and long-term variation trends of the CO column content in the atmosphere in these regions are discussed. An evident variation trend of anthropogenic CO in the atmosphere for the Beijing region is not observed during 1992–2012, while for the Moscow region, it decreases yearly by about 1.4% for the same period. High CO concentrations appear quite frequently in Beijing, but much less frequently in Moscow, except during the natural fire events in summer 2010. From back trajectory analysis, the high CO concentration observed in Beijing can be attributed to the intensive CO emission sources in its surrounding areas.

Influence of internal gravity waves on meteorological fields and gas constituents near Moscow and Beijing

The influence of internal gravity waves on the spatial coherence and temporal variability of the atmospheric pressure, wind velocity, and gas constituents near Moscow and Beijing is studied in the mesoscale range of periods: from a few tens of seconds to several hours. The results of simultaneous measurements of variations in the atmospheric pressure (using a network of spaced microbarographs), wind velocity at different heights of the atmospheric boundary layer, and gas constituents are given for each city. The wave structures are filtered using a coherence analysis of the atmospheric pressure variations at different measurement sites. The dominant periods and the coherences, phase speeds, and horizontal scales of variations corresponding to these periods are estimated. The general mechanism of the influence of wave structures on meteorological fields and gas constituents is discussed, which is independent of the measurement site and the specificity of meteorological conditions.

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.