Aerosol seasonal variations over urban–industrial regions in Ukraine according to AERONET and POLDER measurements

Atmos. Meas. Tech., 7, 1459–1474, 2014 www.atmos-meas-tech.net/7/1459/2014/ doi:10.5194/amt-7-1459-2014 © Author(s) 2014. CC Attribution 3.0 License. Aerosol seasonal variations over urban–industrial regions in Ukraine according to AERONET and POLDER measurements G. Milinevsky1 , V. Danylevsky1 , V. Bovchaliuk1,2 , A. Bovchaliuk3 , Ph. Goloub2 , O. Dubovik2 , V. Kabashnikov4 , A. Chaikovsky4 , N. Miatselskaya4 , M. Mishchenko5 , and M. Sosonkin3 1 Taras Shevchenko National University of Kyiv, Kyiv, Ukraine 2 Laboratoire d’Optique Atmosphérique, CNRS – Université de Lille 1, Villeneuve d’Ascq, France 3 Main Astronomical Observatory, National Academy of Sciences of Ukraine, Kyiv, Ukraine 4 Institute of Physics, Laboratory of Scattering Media, Minsk, Belarus 5 NASA Goddard Institute for Space Studies, New York, USA Correspondence to: G. Milinevsky () Received: 8 November 2013 – Published in Atmos. Meas. Tech. Discuss.: 13 December 2013 Revised: 5 April 2014 – Accepted: 14 April 2014 – Published: 27 May 2014 Abstract. The paper presents an investigation of aerosol seasonal variations in several urban–industrial regions in Ukraine. Our analysis of seasonal variations of optical and physical aerosol parameters is based on the sun-photometer 2008–2013 data from two urban ground-based AERONET (AErosol RObotic NETwork) sites in Ukraine (Kyiv, Lugansk) as well as on satellite POLDER instrument data for urban–industrial areas in Ukraine. We also analyzed the data from one AERONET site in Belarus (Minsk) in order to compare with the Ukrainian sites. Aerosol amount and optical depth (AOD) values in the atmosphere columns over the large urbanized areas like Kyiv and Minsk have maximum values in the spring (April–May) and late summer (August), whereas minimum values are observed in late autumn. The results show that fine-mode particles are most frequently detected during the spring and late summer seasons. The analysis of the seasonal AOD variations over the urban–industrial areas in the eastern and central parts of Ukraine according to both ground-based and POLDER data exhibits the similar traits. The seasonal variation similarity in the regions denotes the resemblance in basic aerosol sources that are closely related to properties of aerosol particles. The behavior of basic aerosol parameters in the western part of Ukraine is different from eastern and central regions and shows an earlier appearance of the spring and summer AOD maxima. Spectral single-scattering albedo, complex refractive index and size distribution of aerosol particles in the atmosphere column over Kyiv have different behavior for warm (April–October) and cold seasons. The seasonal features of fine and coarse aerosol particle behavior over the Kyiv site were analyzed. A prevailing influence of the fine-mode particles on the optical properties of the aerosol layer over the region has been established. The back-trajectory and cluster analysis techniques were applied to study the seasonal back trajectories and prevailing directions of the arrived air mass for the Kyiv and Minsk sites. 1 Introduction Aerosol seasonal variations have been investigated in different regions with various ground-based (Gerasopoulos et al., 2007; Jaroslawski and Pietruczuk, 2010; Rana et al., 2009; Andrews et al., 2011; Leskinen et al., 2012; Liu et al., 2012; Pietruczuk and Chaikovsky, 2012), satellite (e.g., Barnaba and Gobbi, 2004; Song et al., 2008), combined groundbased and satellite (e.g., Zawadzka et al., 2013; Bovchaliuk et al., 2013), and balloon-borne (Hara et al., 2011, 2013) techniques for aerosol measurements. The NASA AErosol RObotic NETwork (AERONET; Holben et al., 1998; http: //aeronet.gsfc.nasa.gov/) data are used intensively in such studies. For example, AERONET sun-photometer observations have recently been used (Liu et al., 2012) for study of the seasonal variations in aerosol optical properties in China, including the aerosol optical depth (AOD), Ångström exponent (AE), and single-scattering albedo (SSA). For the Published by Copernicus Publications on behalf of the European Geosciences Union. 1460 G. Milinevsky et al.: Aerosol seasonal variations over urban–industrial regions eastern China region it has been concluded that the AOD is largest in the summer and smallest in the winter, whereas the SSA values exhibit weak seasonal variations with the smallest values during the winter and the largest during the summer. The seasonal behavior of aerosol optical properties determined from vertically resolved in situ measurements over rural Oklahoma, USA, were compared with AERONET data by Andrews et al. (2011). Combined ground-based (AERONET/PHOTONS) and satellite (Moderate-Resolution Imaging Spectrometer, or MODIS) data have been used to study seasonal aerosol content and properties over Europe for 2000–2009 and their impact on ultraviolet (UV) radiance (Chubarova, 2009). The analysis by Jaroslawski and Pietruczuk (2010) of seasonal AOD variations at Belsk (Poland) based on data over the 2002–2007 period reveals two AOD maxima: in April and July–August. In the paper by Zawadzka et al. (2013), the difference in AOD between an urban area (Warsaw) and a rural area (Belsk) during 2005– 2011 was investigated. The estimated influence of urban-area emissions on the AOD was reported as being less than 15 %. As reported by Uscka-Kowalkowska (2013), the extinction of direct solar radiation has been studied during the period 1964–2003 in an elevated mountainous region of Poland that can be considered as a non-urban setting. The increased extinction was observed during the spring and summer seasons and showed traits similar to those in urban–industrial areas of eastern Europe. This suggests that the behavior of the aerosol content in this region is governed mainly by the aerosol transport. In previous analyses (e.g., see Chubarova, 2009; Giles et al., 2012; Pietruczuk and Chaikovsky, 2012; Zawadzka et al., 2013), the eastern European region is considered to be the source of urban–industrial aerosols according to the general aerosol type classification by Dubovik et al. (2002). Indeed, there are many existing and potential aerosol pollution sources in this region, including Ukraine: intensive transport and agriculture, heavy industry, open steppe fields, and mining. Furthermore, this region is characterized by numerous forest, grassland, and peat wildfires, and also can sometimes be considered as a source of biomass burning aerosols (Barnaba et al., 2011; Witte et al., 2011; Bovchaliuk et al., 2013). The steppe regions of southern Ukraine also experience periodical dust storms (e.g., Birmili et al., 2008). The investigated region is mostly flat terrain with altitude difference between the center and east of Ukraine of about 300 m above sea level (a.s.l.). The developed heavy industry is concentrated in the Donetsk, Lugansk, and Kharkiv metropolitan areas; industry and open mines are typical of east-central Ukraine (Dnipropetr (...truncated)