G. I. Gorchakov

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. ,

Variations in gaseous pollutants in the air basin of Moscow

Variations in the concentrations of gaseous pollutants in the air basin of Moscow are statistically analyzed. The basic statistical characteristics of variations in the concentrations of carbon monoxide, nitric oxide, nitrogen dioxide, ozone, formaldehyde, and a number of aromatic compounds are calculated. The main properties of intradiurnal, synoptic, seasonal, and interannual variations in the concentrations of gaseous pollutants are described. The power spectral densities of variations in the concentrations of carbon monoxide and nitrogen oxides are analyzed. The contributions made by variations in the concentration of carbon monoxide on different time scales to the total variance are calculated. The effect of the atmospheric air polluted with carbon monoxide and nitrogen oxides on the ecological situation in the city is estimated. The probabilities of an excess over the single maximum allowable concentrations are determined for carbon monoxide and nitrogen oxides. The absorption of shortwave solar radiation by nitrogen dioxide in the atmospheric boundary layer is estimated.

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.

Evolution and radiation effects of the extreme smoke pollution over the european part of Russia in the summer of 2010

Using aerospace monitoring data we performedspatiotemporal analysis of the evolution of smokeaerosol during the period of forest and peat bog fires onthe European territory of Russia (ETR) in the summerof 2010. It is shown that the spatial structure of theETR smoke pollution and its temporal variations wereclosely related to the processes of largescale atmospheric dynamics. In the period from August 5 toAugust 9 the region of maximum smoke pollutionmade a complete clockwise rotation around Moscowremaining at a distance of 200–650 km from the megacity, which prevented even a greater smoke pollutionof Moscow (compared with the pollution observedduring these days). Statistical characteristics of variations in the aerosol optical depth (AOD, ) at the wavelength of 0.55 m (0.55) over the ETR during the wildfires are presented. The mass content of smoke aerosolin the atmospheric column is evaluated as well. We alsoestimated regional mean shortwave radiative forcing ofthe smoke aerosol at the top and at the bottom of theatmosphere. The distributions of the aerosol radiativeforcing (ARF) over the ETR during the fires are presented and their significant spatial inhomogeneitiesare revealed. MODIS AOD data are validated by comparison with AOD data obtained at the AERONETstation Zvenigorod.A spacious and longliving blocking anticyclonethat settled over the ETR in the summer of 2010 [1]radically changed the thermal and hydrologicalregimes of the region [2]. A long drought facilitatedthe appearance and spreading of the forest and peatbog fires, which led to strong aerosol and gas pollutionof the atmosphere in the region that lasted many days[3–6]. The high concentration of smoke aerosol in theair caused strong changes in the radiation regime ofthe atmosphere [7].Unlike the groundbased data, the satellite AODdata along with the estimates of the local smoke loading allow to study the geographical distribution of thesmoke aerosol and its time evolution, obtain estimatesof the spatially distributed (regional) radiative effectsof the smoke, and also retrieve the spatial pattern ofthe ARF. This information is needed for correct estimates of aerosol particle emission during the fires,solution of various climatic problems, and testing ofchemical transport models. In this work, we use thesatellite AOD observations from the MODIS instruments [8, 9] to study the spatiotemporal evolution ofthe AOD and shortwave radiation forcing of the smokeaerosol during the forest an d peat bog fires in the ETRin the summer of 2010. We assume that the ETR is theterritory bounded by coordinates 47°–65° N and 25°–55° E with an area of approximately 3.6 mln. km

Influence of a solar eclipse on thermal stratification and the turbulence regime

During the total solar eclipse on March 29, 2006 [1], researchers in Kislovodsk measured variations in the flux of the total shortwave radiation, meteorological elements (wind speed and direction and relative air humidity), and turbulence parameters in the surface atmospheric layer, vertical profiles of air temperature in the layer 0‐600 m, functions of particle size distribution (0.20‐1.50 µ m), and concentrations of light ions. It was found that the decrease in the maximum air temperature caused by the eclipse reached 3.5°C in the surface atmospheric layer and approximately 2°C at an altitude of 600 m a.s.l. After the full phase of the eclipse, turbulent kinetic energy decreased by a factor of 2.5, dispersion of the vertical component of the wind speed decreased by a factor of 2.3, turbulent heat flux decreased by a factor of 3.5, and dispersion of turbulent pulsations of air temperature decreased by a factor of 10. Despite the long history of investigations of eclipses [2], the influence of the solar eclipses on processes in the boundary atmospheric layer has not yet been studied sufficiently enough [3‐5]. It is clear that a solar eclipse should lead to variations in the thermal regime of the boundary atmospheric layer, increase in the relative air humidity, and consequent increase in the size of aerosol particles. Variations in the parameters of aerosol along with other factors can change notably the electric characteristics of the surface atmosphere [6]. Decrease in the near-surface air temperature can also lead to variations in the turbulence regime. In order to study the quantitative variations in the above-mentioned parameters of the lower atmosphere during the total solar eclipse in the last decade of March in Kislovodsk (altitude ~900 m a.s.l.), the following measurements were carried out at the urban meteorological station: flux F of total shortwave radiation (CNR1 net radiometer (Kipp and Zonen, Netherlands); accuracy ± 10 W/m 2 ), meteorological parameters (accuracy of measurements: air temperature ± 0.3°C , relative humidity ± 5% , components of wind speed ± 0.15 m/s), turbulent pulsations (digitization step 0.1 s) of three components of wind speed and air temperature using a Meteo-2M acoustic meteorological station (Institute of Atmospheric Optics, Tomsk), vertical profiles of air temperature (time averaging 5 min, spatial averaging 50 m, accuracy of measurements ± 0.5°C ) in layer 0‐ 600 m (MTP-5 UHF microwave profiler of the Central Aerological Observatory [8]), concentrations of negative light ions using a SIGMA-1 counter of aeroions (accuracy of each measurement ± 30% , time constant 1.5 s, mobility of ions >0.4 cm 2 / W · s), and distribution function of the dry base of aerosol particles in the size range 0.20‐1.50 µ m (LAS-P laser spectrometer of aerosols, averaging time of differential countable concentrations of particles 15 s, and random error of measurements of countable concentrations 20%). Calibration of the laser spectrometer was carried out using nuclear filters, which allowed us to increase the accuracy of determination of the boundaries of the particle size ranges determined by the spectrometer.

The Moscow heat island in the blocking anticyclone during summer 2010

736 Using the thermal sounding data for Moscow and the Moscow region by three MTP 5 SHF profilome ters [1] in the atmospheric lower layer 600 m thick and the data of monitoring the air temperature by the net work of automatic stations of control of the atmo spheric air quality at the State Funded Institution Mosecomonitoring, the values of the effect of the urban heat island (UHI) were obtained [2] in the atmospheric surface and boundary layers in the long lived blocking anticyclone during summer 2010. In the period of July 22–29, 2010, the heat island effect was 0.9–4.1°C, on average, in the atmospheric surface layer and on August 1–10, 2010, it varied from 1.5 to 5.0°C in the strongly smoggy atmosphere in various districts of the city. In Losinyi Ostrov National Park, there was a decrease in the surface temperature (“cold island”) by 2–5°C during these periods as compared to the Moscow Region. According to the data of ther mal sounding for four periods in the blocking anticy clone and during one period of observations after the break of the anticyclone, the vertical profiles of the deviations of the average daily amplitudes of variations in the air temperature (the UHI effect) are calculated in the layer of 25–600 m above the level of the under lying surface on the territories of Moscow State Uni versity (Department of Physics) and the Federal State Financed Institution Central Aerological Observatory in the city of Dolgoprudny from the respective diurnal amplitude of the air temperature at the Zvenigorod Scientific Station (ZSS) of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (rural area). It is established that the heat island exerted the maximum effect at the height of 25 m (MSU): from 2.5 to 4.3°C in the unsmoggy atmo sphere and to 5.8°C in the smoggy atmosphere under the blocking anticyclone and 0.9°C after the anticy clone broke. Unlike the typical summer conditions, the UHI effect did not tend to zero in the blocking anticyclone as the height of sounding increased; as a rule, it reached the minimum value of 0.6–2.5 (at MSU and CAO) at the height of 200–400 m. At the level of 600 m, the studied effect in the blocking anticyclone varied from 0.8 to 2.3°C for the station at MSU and from 1.2 to 3.1°C for CAO. The deviations in the daily amplitudes of the air temperatures that were recorded in the upper part of the sounded layer (300–600 m) at MSU and CAO from the diurnal amplitudes of tem perature at ZSS could have been caused by the strong thermal anomaly in the lower troposphere that was typical of the blocking anticyclone [3]. In the blocking anticyclone, the strongest temperature inversions were observed at the ZSS in the layer of 300–350 m: in the unsmoggy and weakly smoggy atmosphere, they were 2.4–3.3°C and in the strongly smoggy atmosphere, 4.6–5.9°C. At the stations at MSU and CAO, the strength of inversions was usually noticeably less.

Aerospace monitoring of smoke aerosol over the European part of Russia in the period of massive forest and peatbog fires in July–August of 2010

Based on MODIS satellite observations of aerosol optical depth (AOD) and active fires, as well as on data from the network for aerological radio sounding, we analyzed the spatiotemporal evolution of smoke aerosol on the territory of European Russia (ER) during the period of massive forest and peatbog fires in summer of 2010. An interrelation is found between the structural features of the smoke-polluted regions and the processes of large-scale dynamics. The evolution of the smoke aerosol plume in the metropolitan area is described in detail. The statistical characteristics of AOD variations over ER during the fire period are calculated. The total column smoke aerosol is estimated. The radiation effects of smoke pollution of the atmosphere in the region are studied. The time evolution of the regional average shortwave radiative forcing of smoke aerosol at the top and bottom of the atmosphere is presented, together with the spatial distribution of local values of the radiative forcing in the period of maximum smoke pollution of ER. A statistically significant relation is found between MODIS-diagnosed number of active fires and wind speed and direction. The MODIS data on AOD are validated against observations at the AERONET station in Zvenigorod.

Hydrocarbons in an Urban Atmosphere

Statistical characteristics of variations in surface-layer concentrations of methane, non-methane and aromatic hydrocarbons, carbon dioxide, and formaldehyde are compared with the characteristics of variations in the concentration of carbon monoxide in the air basin of Moscow. Differences in the annual cycle of concentrations of methane, carbon dioxide, non-methane hydrocarbons, and carbon monoxide are determined. It is found that the maximum concentration of carbon monoxide at most sites with an elevated surface-air pollution level and over the city as a whole tends to occur in the summer season. The seasonal variability of the diurnal mean cycle of methane, carbon dioxide, and non-methane and aromatic hydrocarbons is analyzed.

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.