V. M. Kopeikin

Optical and microphysical parameters of the aerosol in the smoky atmosphere of the Moscow region in 2010

513 According to the data of ecological monitoring in the city of Moscow and Moscow region, it was found that during the period of the smoky atmosphere in the summer of 2010, the mass concentration of the smoke aerosol with the diameter of particles less than 10 μm (PM10) reached extreme values for Moscow, 1.6– 1.7 mg/m 3 . According to the measurements at the Meteorological Observatory of the Moscow State University (MO MSU) and in the Moscow region at the Zvenigorod Scientific Station of the Oboukhov Institute of Atmospheric Physics, Russian Academy of Sciences (ZSS IAP), based on the data of sun photom� eters CIMEL, which are included in the global moni� toring network in the atmosphere column AERONET, the maximum values of the optical aerosol thickness at a wavelength of 500 nm during the peatbog forest fires exceeded 4.5. Analysis of the spectropolarimetric measurements demonstrated that the optical charac� teristics of the studied smoke in the surface layer have a significant difference from the optical characteristics of the smoke from the forest and peatbog fires in 2002 [1, 2]. The microphysical properties of the smoke in 2002 retrieved from the data of optical characteristic measurements are also notably different from the microphysical characteristics observed previously, including the smoke in 2002 in the Moscow region. In 2010, during the period of the intensive smoky atmo� sphere, the distribution function for the aerosol parti� cles appeared very narrow and the major part of the volume (mass) of the aerosol smoke particles belonged to the submicrometer range. ,

Satellite and ground-based monitoring of smoke in the atmosphere during the summer wildfires in European Russia in 2010 and Siberia in 2012

Using Moderate Resolution Imaging Spectroradiometer (MODIS) (Aqua and Terra satellites) and in situ observations, a comparative analysis of two large-scale smoke events caused by the summer wildfires in European Russia (ER) in 2010 and Western Siberia (WS) in 2012 was carried out. In the 5-day periods of the extreme smoke pollution (5–9 August 2010 in ER and 27–31 July 2012 in WS), the number of active fires in the equal territories, confined by the coordinates 47°–65° N, 25°–55° E and 51°–70° N, 71°–104° E, was found to be 4754 for ER and 3823 for WS. With this, the regional mean aerosol optical depths (AODs) were found to be (1.02 ± 0.02) and (1.00 ± 0.04), not much differing for both the events. The regional mean aerosol radiative forcing effects at the top (R1) and the bottom (R2) of the atmosphere over ER/WS according to MODIS observations were estimated to be (−61 ± 1) and (−54 ± 2) W m−2, and (−107 ± 2) and (−96 ± 3) W m−2, respectively. At the same time, the local values of AOD and the local absolute values of R1 and R2 over WS were considerably higher than those over ER. MODIS AOD (L3) data during the wildfires of 2010 were validated by AOD data obtained by the sun-sky photometer CIMEL, operating at the AERONET station Zvenigorod. The rates of radiative heating of the smoky atmosphere over ER and WS were also estimated and compared with the existed temperature anomalies, obtained using National Centers for Environmental Prediction National Center for Atmospheric Research reanalysis data. Optical and microphysical properties of smoke aerosols during the wildfires in ER and WS also revealed some similar characteristics. The aerosols were mostly found in the submicron-size fraction and characterized by very high single-scattering albedos (0.95–0.98). In the dense smoke conditions, the degree of linear polarization at the scattering angle 90° during both the events decreased to negative values ranging between −0.1 and −0.15. The optical properties of smoke aerosols were mainly conditioned by unusually narrow particle size distribution.

Measurements of soot aerosol content in the near-water atmospheric layer in the southern and northern hemispheres

We present the results of mass soot concentration measurements in the near-water layer of the atmosphere during two cruises of the “Academic Fedorov” research vessel (from September 25 to October 23, 1998, on a route from St. Petersburg to Franz Joseph Land and from November 8, 1999, to April 30, 2000, on a route from St. Petersburg to Antarctica and the Southern Ocean [I’m not sure this exists.]), the 27th cruise of the “Academician Ioffe” research vessel (from April 6 to May 19, 2009, from Ushuaia (Tierra del Fuego) to Gdansk (Poland)), and at the Russian Antarctic Bellingshausen station (from December 20, 2001, to March 11, 2002). It is shown that the soot content in the atmosphere above the Arctic Ocean in October 1998 is comparable to that obtained at stationary stations in 1989–1992. The latitudinal dependence (less soot content with increases in latitude) is observed in the Southern Hemisphere. The average concentration of soot at Bellingshausen station and in the Southern Ocean is 19–28 ng/m3 and is comparable with the level of pollution at the foreign McMurdo and Ferraz stations.

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.

The specific charge of saltation sand particles in arid territories

Original Russian Text

The effect of atmospheric circulation on the evolution and radiative forcing of smoke aerosol over European Russia during the summer of 2010

The evolution of smoke plume over European Russia (ER) during the massive forest and peatbog fires of summer 2010 has been studied using observations of aerosol optical depth (AOD) from MODIS instruments (both Aqua and Terra platforms), objective analysis of meteorological fields performed at the Russian Hydrometeorological Research Center, NCEP/NCAR reanalysis, as well as upper air data. A relation between the structure inhomogeneities of the AOD field and regional atmospheric circulation has been found. It is shown that, on August 5–9, 2010, the maximum of smoke pollution did complete turn around Moscow, while remaining at a distance of 200 to 650 km from the megacity. Both regionally averaged shortwave aerosol radiative forcings (ARFs) at the top and the bottom of the atmosphere are estimated for the period of extreme smoke pollution over ER. The spatial distributions of ARF values over the territory of the region and the estimates of the local and spatially distributed thermal effects of smoke aerosol are given. It is shown that, on August 5–9, 2010, the spatial distribution of AOD and the calculated thermal effects of smoke aerosol were in agreement with the spatial distributions of air-temperature anomalies observed in the lower 1.5-km layer of the atmosphere. MODIS’s AOD data obtained during the wildfires were validated by AOD observations from the CIMEL sun photometer operated at the AERONET station Zvenigorod.

Influence of the saffman force, lift force, and electric force on sand grain transport in a wind–sand flow

Quasi-horizontal trajectories of salting sand grains were found using high-speed video-recording in the desertified territory of the Astrakhan region. The sizes and displacement velocities of the saltating sand grains were determined. A piecewise logarithmic approximation of the wind profile in a quasi-stationary wind–sand flow is suggested, which is consistent with the data of observations and modeling. It was established that, in the regime of stationary saltation, the wind profile in the lower saltation layer of the wind–sand flow depends only slightly on the wind profile variations in the upper saltation layer. The vertical profiles of the horizontal wind component gradient in a quasi-stationary wind–sand flow were calculated and plotted. It was shown using high-speed video recording of the trajectory of a sand grain with an approximate diameter of 95 μm that the weightlessness condition in the desertified territory of the Astrakhan region in a stationary wind–sand flow is satisfied at a height of approximately 0.15 mm. The electric parameters of a wind–sand flow, which can provide for compensation of the force of gravity by the electric force, were estimated. In particular, if the specific charge of a sand grain is 100 μC/kg, the force of gravity applied to the sand grain can be compensated by the electric force if the vertical component of the electric field in a wind–sand flow reaches approximately 100 kV/m. It was shown that the quasi-horizontal transport of sand grains in the lower millimeter saltation layer observed in the desertified territory can be explained by the joint action of the aerodynamic drag, the force of gravity, the Saffman force, the lift force, and the electric force.

The influence of solar eclipse on the processes in the atmospheric boundary layer

The effects of an eclipse on the atmospheric boundary layer in Novosibirsk are studied in a period of total solar eclipse on August 1, 2008. Variations caused by the eclipse of the temperature near the ground, vertical temperature profiles in the atmospheric boundary layer, and turbulence parameters are determined. Variations of the total water vapor content and aerosol parameters in the near-ground atmospheric layer during the solar eclipse are analyzed.

Moscow smoke haze in October 2014. Variations in the aerosol mass concentration

Variations in the aerosol mass concentration in the smoky atmosphere of the Moscow region in autumn 2014 have been analyzed. The soot mass fraction and ratio between the PM2.5 and PM10 mass concentrations were typical of the fires in boreal forests. The smoke event in the Moscow region was due to the long-range transfer of the smoke aerosol, which was confirmed by a joint analysis of aerospace monitoring data and inverse trajectories of air mass transfer, and local fires in the Moscow region. As a result, statistical parameters of variations in the smoke aerosol mass concentrations were atypical, including empirical distribution functions and power spectra.

Variations in the specific charge of saltating sand in a windsand flux over a desertified area

The probability distribution of specific charge of saltating sand over a desertified area has been obtained for the first time. The specific charge of the saltating sand varied between 10 and 150 μC/kg (48.5 μC/kg on the average) according to measurements over a desertified area in Kalmykia (July 2014). An original setup has been designed whereby the saltating sand concentrations, electric current fluctuations, and turbulent pulsations of the wind velocity have been measured over the desertified area in Kalmykia. Regularities in transformations of the statistical parameters from the wind speed to the sand grain concentration and further to the electric current of the saltation due to nonlinear processes in a windsand flux have been ascertained for the first time, including variations in the empirical distribution functions and fluctuation power spectra.