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e-mail: m.andreae@mpic.de. Received May 27, 2014. Abstract—An assessment of atmospheric aerosol composition in middle and high latitudes of Eurasia has.
ISSN 1875-3728, Geography and Natural Resources, 2015, Vol. 36, No. 1, pp. 25-30. © Pleiades Publishing, Ltd., 2015. Original Russian Text © A.V. Panov, J. Heintzenberg, W. Birmili, P. Seifert, X. Chi, A.V. Timokhina, M.O. Andreae, 2015, published in Geography and Natural Resources, 2015, Vol. 36, No. 1, pp. 30-36.

Spatial Distribution of Atmospheric Aerosols Over the Territory of Eurasia in Middle and High Latitudes a

A. V. Panova, J. Heintzenbergb, W. Birmilib, P. Seifertb, X. Chic, A. V. Timokhinaa, and M. O. Andreaec

Sukachev Institute of Forest, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia b Leibniz Institute for Tropospheric Research, Leipzig, Germany c Max Planck Institute for Chemistry, Mainz, Germany e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] Received May 27, 2014

Abstract—An assessment of atmospheric aerosol composition in middle and high latitudes of Eurasia has been made by integrating long-term (longer than five years) instrumental observations of microphysical and optical characteristics of atmospheric aerosols at the Zotino Tall Tower Observatory (ZOTTO) in the middletaiga subzone of Yenisei Siberia and Lagrangian trajectory modeling. A correlative analysis of the findings and data for anthropogenic and forest fire emissions revealed signals existing in its formation, and their origin was assessed. DOI: 10.1134/S1875372815010047 Keywords: atmosphere, aerosol, Middle Siberia, boreal forests, trajectory modeling.

FORMULATION OF THE PROBLEM Atmospheric aerosols constitute a very important regulatory factor for the global climate system. Study of the quantitative and qualitative parameters of aerosols that are formed in background naturalclimatic conditions and are determined solely by natural biosphere cycles is a necessary requirement for verification of existing climate models [1–3]. The boreal (taiga) ecosystems of Eurasia serve as a very important source of formation of volatile organic compounds of a biogenic origin, and of atmospheric aerosols [4, 5]. The absence of assessments of the aerosol component over this extensive background territory of the northern hemisphere was a motivational factor for the creation of the ZOTTO Observatory in the heart of the Eurasian Continent, in the middle-taiga subzone of Siberia, where a year-round instrumental monitoring of the atmospheric gas and aerosol composition has been carried on since 2006. The research results have clearly demonstrated the natural formation of aerosols in the study area as well as a significant influence of their transcontinental transfer [6, 7], which furnishes a unique opportunity to assess the existing signals in the formation of the atmospheric aerosol composition for a considerable part of the Eurasian Continent. Based on integrating the results of six-yearlong (2006–2012) instrumental measurements of

microphysical and optical characteristics of atmospheric aerosols and Lagrangian trajectory transfer of air masses, we made assessments of the spatial distribution of aerosols over a significant part of the territory of Eurasia. The findings provide a more penetrating insight into the atmospheric aerosol composition in middle and high latitudes of Eurasia. OBJECTS AND METHODS The study area is located in the middle-taiga subzone of Yenisei Siberia, in the surroundings of the settlement of Zlotino (60º N, 90º E) of the Turukhanskii district of Krasnoyarsk krai. The area has a continental climate, with severe and snowy winters, and moderately warm humid summers. Topography of the territory is represented by an alternation of planate hills, ramparts and low ridges. The geomorphology, lithology and climate contribute to significant bogginess characteristic for 60% of the territory. The structure of vegetation cover in the study area is determined by the mosaic pattern of forest-bog biogeocenoses occurring at different elements of landscape [8]. The measurement tower (304 m), the laboratory and the gas analysis system for monitoring the atmospheric constituents were installed during the period from 2004 to 2006. Detailed information regarding the 25

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observatory and the complex of gas analysis and aerosol measurement equipment installed in place is provided at www.zottoproject.org as well as in [6, 7, 9–11]. For investigating aerosols the flow of atmospheric air (40 L/min) was supplied to the laboratory through a 300 m inlet pipe. Round the year, in the real-time mode, measurements were made of the aerosol concentration and disperse composition in the range from 10 to 835 nm, the aerosol absorption coefficients (σabs) and the light scattering (σscat). Further, on the basis of σabs and σscat , the albedo of single scattering (ωasing) was calculated. The backward 10-day 3D trajectories of the transfer of air masses were calculated by using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) [1], i.e. a computer model provided by the ARL NOAA Laboratory [12]. A calculation of the trajectories was done, based on the set of meteorological fields of the Global Data Analysis System (GDAS), having a 3-hour period of measurements, a spatial resolution of 1º, and the profile of pressure levels (1000, 925, 850 hPa, etc.). Data of instrumental measurements were integrated with results of trajectory analysis, in accordance with the technique described in [6], based mainly on Dorling’s approach with the use of the method of k-means. The analysis was complemented by parameters for anthropogenic emissions of carbon-containing gases (CO) from the Global Atmospheric Research Database (EDGAR v.4.2) for 2008 and fire emissions (mass concentration of particles, PM 2.5) from the Global Fire Emissions Database (GFED 3.1) for the period 2006–2011. A graphical representation of results used the IGOR 6.2 software package (Wavemetrics Inc., USA). RESULTS AND DISCUSSION The calculated (N, cm–3) and volumetric (V, µm3 cm–3) concentrations of atmospheric aerosols are their main integral microphyical parameters, while the disperse composition largely determined, period and conditions of occurrence of aerosols in the air environment. Along with the microphysical parameters, the light scattering and absorption serve as the crucial optical properties of aerosols, permitting the sources of their formation to be diagnosed. The mean statistical characteristics of microphysical parameters of aerosols, both integral and seasonal, and of their optical properties were discussed in earlier publications [6, 7]. Based on integrating the results of six-year-long (2006–2012) instrumental measurements of aerosol characteristics and Lagrangian trajectory modeling of air masses, an assessment was made of the integral values of N and V (Fig. 1, а, b), the disperse composition of aerosols in the range from 10 to 835 nm, encompassing aerosols of the nucleation mode (< 26 nm), the Aitken mode (26–80 nm), the accumulation mode (80–835 nm) (Fig. 2, а-c), and their optical properties (see Fig. 2, d-f) in the atmosphere of middle and high latitudes of Eurasia (above 40º N). On the whole, over most of the high-latitude areas

of Siberia and of the northeastern territory of Eurasia (above 60º N) there occur relatively low values of the calculated (700–1000 cm–3) and volumetric (2–4 µm3 cm–3) atmospheric aerosol concentrations. In Central Siberia, in the area where the ZOTTO observatory is located, aerosol concentration is, to a larger extent, determined by natural biosphere cycles, and by the influence of clean maritime air masses from the water areas of the Arctic and Pacific Oceans and the westerly transfer of the continental air from sparsely populated high-latitude territories of Western Siberia. Minimum values of the calculated (400–500 cm–3) and volumetric (1–3 µm3 cm–3) concentrations are observed in the east of the Eurasian Continent, in an extended region (90–110º E) at a relatively large distance from large settlements and industrial centers, between 40 and 50º N over the coast of the Far East. The aforementioned values of atmospheric aerosol characteristics may be treated as background ones for the northeastern territory of Eurasia (above 60º N) in general. More specifically, three regions with increased atmospheric aerosol concentrations were identified: the industrial areas of Europe (up to 1500 cm–3), the territory of Central Asia (1300–1500 cm–3), and the region in Northeastern Siberia (1200–1500 cm–3) (see Fig. 1, а), which is confirmed by the disperse composition of aerosols (see Fig.2, а-c) and their optical properties (see Fig. 2, d-f). In this case, the scattering coefficients (σscat) reach 40–50 mm–1 for these areas, whereas the absorption coefficients (σabs) are not always high, which points to a different origin of the detected aerosol maxima. Thus, the first maximum is observed over the territory of Europe, and further, from west to east, two main belts of increased aerosol concentrations are produced (see Fig. 1, a, b), which lie over the areas of large settlements and industrial centers of Europe, the Near East and Central Asia, which largely points to their anthropogenic origin. This is confirmed by plumes of high σabs (6–8 mm–1) (see Fig. 2, e), accompanying the belts of increased aerosol concentrations and suggests a predominance of anthropogenic sources of burning of fossil fuels leading to high contents of black carbon in the atmosphere [13]. The longest belt extends from Europe to the territory of Southwestern Asia along 40º N, with the values of N ranging from 1000 to 1500 cm–3, and with V of up to 6 µm3 cm–3, while the second belt lies above 50º N and is more pronounced (up to 1500 cm–3) in its eastern part, specifically over the territory of Central Siberia. The disperse composition of the aerosol belts also gives evidence for the anthropogenic character of their formation and points to a predominance of the finedisperse fraction represented by the Aitken mode (Na), and by the accumulation mode (Nac) with the values 300–500 cm–3 (see Fig. 2, b) and 800–1000 cm–3 (see Fig. 2, c), respectively. Further out to the east, the two belts converge at the western boundary of the mountain systems of Central Asia, changing the trajectories of air masses and, obviously, forming between 40 and 60º N and 90 and 110º E an extensive region of

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Fig. 1. Values of the calculated (N, cv–3) (а) and volumetric (V, µm3 cm–3) (b) concentrations of atmospheric aerosols over the territory of Eurasia in middle and high latitudes (as deduced from results of trajectory modeling). Circles show the population size of the cities.

aerosol accumulation, representing the second and the largest maximum over the territory of Eurasia with the values of N and V of up to 1500 cm–3 and 8–10 µm3 cm–3, respectively. On the other hand, the region of increased concentration (80–100 cm–3) of aerosols of the nucleation mode (Nn) also suggests the formation of fine-disperse particles in this area (see Fig. 2, a). For reasons of lithological (topography of the territory) and meteorological conditionality, the results of trajectory analysis do not cover the eastern (mountainous) GEOGRAPHY AND NATURAL RESOURCES

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territories of Central Asia and of China on the east. The third (in size) region of increased aerosol concentrations (1200–1500 cm–3) over the territory of the Eurasian Continent is observed in Northeastern Siberia (above 60º N). The fact that this area does not include any large industrial centers rules out the anthropogenic character of the genesis and permits forest fires to be thought of as being the cause for increased concentrations of atmospheric aerosols. The disperse composition for this territory showed a No. 1

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Fig. 2. Values of Nn, cv–3 (а), Na, cv–3 (b), Nac, cm–3 (c), σscat, mm–1 (d), σabs, mm–1 (e), and ωаsing (f) over the territory of Eurasia in middle and high latitudes (as deduced from results of trajectory modeling). Circles show the population size of the cities. GEOGRAPHY AND NATURAL RESOURCES

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Fig. 2. (Contd.).

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predominance of aerosols of the accumulation mode (Nac) (up to 1500 cm–3), pointing to high ash content in the atmosphere. This is also evidenced by high scattering coefficients (σscat) (see Fig. 2, d), and by the absence of increased values of σabs and ωasing (see Fig. 2, e, f). It is the forest fires in Siberia that lead to emissions of aerosols with low σabs, yet high σscat [14]. The role of fires is also confirmed by GFED data, and this area of Northeastern Siberia (90–160º E, 60–70º N) is particularly prominent when calculating the values and frequency of fire-caused emissions. CONCLUSIONS In closing it may be said that by integrating the results of long-term observations at the ZOTTO observatory in the middle-taiga subzone of Yenisei Siberia and Lagrangian trajectory modeling of the transfer of air masses, it was possible to assess the existing signals in the formation of the atmospheric aerosol composition over the territory of Eurasia in middle and high latitudes. It was found that most of the high-latitude areas of Siberia and of the northeastern territory of Eurasia as a whole (above 60º N) show relatively low aerosol concentrations in the atmosphere, whereas over the territory of Northeastern Siberia there occurs a region of increased aerosol concentrations caused by forest fires. The mid-latitudes exhibit two main belts of increased aerosol concentrations of an anthropogenic origin indicating the location of large settlements and industrial centers. One belt extends from Europe to the territory of Southwestern Asia along 40º N, and the other belt lies above 50º N and is more pronounced in its eastern part, specifically over the territory of Central Siberia. The two belts converge at the western boundary of the mountain systems of Central Asia retarding the advance of air masses, and produce between 40 and 60º N and 90 and 110º E an extensive region of aerosol accumulation. The optical properties (light scattering and absorption) serves as an additional tool for diagnosing the origin of aerosol sources. ACKNOWLEDGMENTS This work was done with financial support under an ISTC project (No. 2757), from the Russian Foundation for Basic Research (13–05–98053), and a grant of the President of the Russian Federation for support of young Russian scientists (MK–1691.2014.5.). A.V. Timokhina’s research on assessing anthropogenic emissions of coal-containing gases was supported by a grant of the Russian Science Foundation (14–24– 00113). REFERENCES 1. Aerosols of Siberia, K.P. Kutsenogii, Ed., Novosibirsk:

Izd-vo SO RAN, 2006 [in Russian]. 2. Kutsenogii, K.P., Monitoring of Atmosphric Aerosols in Siberia, Atmos. Oceanic Opt., vol. 9, issue 06, pp. 446–450.

3. Kutsenogii, K.P. and Kutsenogii, P.K., Aerosols of Siberia. Results of Seven-Year-Long Investigations, Sib. Ekol. Zhurn., 2000, vol. 7, no. 1, pp. 11–20 [in Russian]. 4. Tunved, P., Hansson, H.C., Kerminen, V.-M., Ström, J., Dal Maso, M., Lihavainen, H., Visanen, Y., Aalto, P.P., Komppula, M., and Kulmala, M., High Natural Aerosol Loading Over Boreal Forests, Science, 2006, vol. 312, no. 5771, pp. 261–263. 5. Dal Maso, M., Sogacheva, L., Anisimov, M.P., Arshinov, M., Baklanov, A., Belan, B., Khodzher, T.V., Obolkin, V.A., Staroverova, A., Vlasov, A., Zagaynov, V.A., Lushnikov, A., Lyubovtseva, Y.S., Riipinen, I., Kerminen, V.-M., and Kulmala, M., Aerosol Particle Formation Events at Two Siberian Stations Inside the Boreal Forest, Boreal Env. Res., 2008, vol. 13, no. 2, pp. 81–92. 6. Panov, A.V., Heintzenberg, J., Birmili, W., Otto, R., Chi, X., Zrazhevskaya, G.K., Timokhina, A.V., Verkhovets, S.V., Andreae, M., Onuchin, A.A., Sources, Seasonal Variability, and Trajectories of Atmospheric Aerosols Over Central Siberian Forest Ecosystems, Doklady Earth Sci., 2011, vol. 441, issue 2, pp. 1710–1714. 7. Heintzenberg, J., Birmili, W., Otto, R., Andreae, M.O., Mayer, J. C., Chi, X., and Panov, A., Aerosol Particle Number Size Distributions and Particulate Light Absorption at the ZOTTO Tall Tower (Siberia), 2006–2009, Atmos. Chem. Phys., 2011, vol. 11, no. 1, pp. 1153–1188. 8. Belov, A.V., Vegetation of Western Siberia and Its Mapping, Moscow: Nauka, 1984 [in Russian]. 9. Winderlich, J., Chen, H., Gerbig, C., Seifert, T., Kolle, O., Lavrič, J.V., Kaiser, C., Höfer, A., and Heimann, M., Continuous Low-Maintenance CO2/ CH4/H2O Measurements at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia, Atmos. Meas. Tech., 2010, vol. 3, no. 4, pp. 1113–1128. 10. Birmili, W., Stopfkuchen, K., Hermann, M., Wiedensohler, A., and Heintzenberg, J., Particle Penetration Through a 300 m Inlet Pipe for Sampling Atmospheric Aerosols From a Tall Meteorological Tower, Aerosol Sci. Tech., 2007, vol. 41, issue 9, pp. 811–817. 11. Heintzenberg, J., Birmili, W., Theiss, D., and Kisilyakhiv, Ye., The Atmospheric Aerosol Over Siberia, as Seen From the 300 Meter ZOTTO Tower, Tellus B, 2008, vol. 60, no. 2, pp. 276–285. 12. Draxler, R. and Rolph, G., HYSPLIT (HYbrid SingleParticle Lagrangian Integrated Trajectory) Model Access Via NOAA ARL READY, NOAA Air Resources Laboratory. URL: http://ready.arl.noaa.gov/HYSPLIT. php. Accessed 09.07.2012. 13. Bond, T.C. and Bergstrom, R.W., Light Absorption by Carbonaceous Particles: An Investigative Review, Aerosol Sci. Tech., 2006, vol. 40, issue 1, pp. 27–67. 14. Eck, T.F., Holben, B.N., Reid, J.S., Sinyuk, A., Hyer, E.J., O’Neill, N.T., Shaw, G.E., Vande Castle, J.R., Chapin, F.S., Dubovik, O., Smirnov, A., Vermote, E., Schafer, J.S., Giles,D., Slutsker, I., Sorokine, M., and Newcomb, W.W., Optical Properties of Boreal Region Biomass Burning Aerosols in Central Alaska and Seasonal Variation of Aerosol Optical Depth at an Arctic Coastal Site, J. Geophys. Res., 2009, vol. 114, no. 11, pp. 2156–2202.

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