Simulation of the interannual variations of aerosols in China: role of variations in meteorological parameters

Abstract

Abstract. We used the nested grid version of the global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) to examine the interannual variations (IAVs) of aerosols over heavily polluted regions in China for years [2004][2005][2006][2007][2008][2009][2010][2011][2012]. The role of variations in meteorological parameters was quantified by a simulation with fixed anthropogenic emissions at year 2006 levels and changes in meteorological parameters over (particles with a diameter of 2.5 µm or less) aerosol concentrations exhibited large IAVs in North China (NC; 32-42 • N, 110-120 • E), with regionally averaged absolute percent departure from the mean (APDM) values of 17, 14, 14, and 11 % in December-JanuaryFebruary (DJF), March-April-May (MAM), June-JulyAugust (JJA), and September-October-November (SON), respectively. Over South China (SC; 22-32 • N, 110-120 • E), the IAVs in PM 2.5 were found to be the largest in JJA, with the regional mean APDM values of 14 % in JJA and of about 9 % in other seasons. The concentrations of PM 2.5 over the Sichuan Basin (SCB; 27-33 • N, 102-110 • E) were simulated to have the smallest IAVs among the polluted regions examined in this work, with APDM values of 8-9 % in all seasons. All aerosol species (sulfate, nitrate, ammonium, black carbon, and organic carbon) were simulated to have the largest IAVs over NC in DJF, corresponding to the large variations in meteorological parameters over NC in this season. Process analyses were performed to identify the key meteorological parameters that determined the IAVs of different aerosol species in different regions. While the variations in temperature and specific humidity, which influenced the gasphase formation of sulfate, jointly determined the IAVs of sulfate over NC in both DJF and JJA, wind (or convergence of wind) in DJF and precipitation in JJA were the dominant meteorological factors to influence IAVs of sulfate over SC and the SCB. The IAVs in temperature and specific humidity influenced gas-to-aerosol partitioning, which were the major factors that led to the IAVs of nitrate aerosol in China. The IAVs in wind and precipitation were found to drive the IAVs of organic carbon aerosol. We also compared the IAVs of aerosols simulated with variations in meteorological parameters alone with those simulated with variations in anthropogenic emissions alone; the variations in meteorological fields were found to dominate the IAVs of aerosols in northern and southern China over 2004-2012. Considering that the IAVs in meteorological fields are mainly associated with natural variability in the climate system, the IAVs in aerosol concentrations driven by meteorological parameters have important implications for the effectiveness of shortterm air quality control strategies in China.

A Comparison of Meteorology-Driven Interannual Variations of Surface Aerosol Concentrations in the Eastern United States, Eastern China, and Europe

“…The dominant effect of WS in winter over eastern China has been reported by many previous studies (Zhao et al 2013;Mu and Liao 2014;Zhou et al 2015;Qu et al 2015;Li et al 2015), as a result of the IAVs of the intensity of Eastern Asian Winter Monsoon (EAWM) (Niu et al 2010;Zhou et al 2015;Li et al 2015). In summer, the intensive influences of RH on variations of aerosol concentrations have also been shown by many studies.…”

“…S1). The magnitude and spatial distribution of simulated aerosols in the GEOS-Chem model have been evaluated extensively in previous studies for the US (Park et al 2003(Park et al , 2004Heald et al 2006;van Donkelaar et al 2006;Fu et al 2009;Drury et al 2010;Leibensperger et al 2011;Zhang et al 2012a), China (Zhang et al 2012b;Wang et al 2013) Mu and Liao (2014). Our simulation by GEOS-Chem also captures the temporal variations of PM 2.5 concentrations in the eastern US, eastern China and Europe (see supplementary material, Fig.…”

“…Observational and modeling studies have reported high aerosol concentrations in the eastern United States (US) (Malm 2004;Park et al 2003Park et al , 2004Walker et al 2012), eastern China (Zhang et al 2012b;Wang et al 2013;Mu and Liao 2014), and Europe (Megaritis et al 2014;Andersson et al 2007) as a result of the large anthropogenic emissions of aerosols and aerosol precursors in these regions (Dutkiewicz et al 2000;Vestreng et al 2007;Hand et al 2012;Mijling et al 2013). Previous studies also showed that the interannual variations (IAVs) of aerosols were significant in the eastern US (Alston et al 2012), eastern China (Yang et al 2011;Mu and Liao 2014), and Europe (Andersson et al 2007).…”

“…Observational and modeling studies have reported high aerosol concentrations in the eastern United States (US) (Malm 2004;Park et al 2003Park et al , 2004Walker et al 2012), eastern China (Zhang et al 2012b;Wang et al 2013;Mu and Liao 2014), and Europe (Megaritis et al 2014;Andersson et al 2007) as a result of the large anthropogenic emissions of aerosols and aerosol precursors in these regions (Dutkiewicz et al 2000;Vestreng et al 2007;Hand et al 2012;Mijling et al 2013). Previous studies also showed that the interannual variations (IAVs) of aerosols were significant in the eastern US (Alston et al 2012), eastern China (Yang et al 2011;Mu and Liao 2014), and Europe (Andersson et al 2007). The IAVs in aerosol concentrations were found to be sensitive to the IAVs in anthropogenic emissions of aerosols and aerosol precursors (Mylona 1996;Irie 2005;Ohara et al 2007;Vestreng et al 2007;Xing et al 2013) and in meteorological conditions, since the meteorology modulates the processes of dilution, transport, deposition, and chemical reaction (Andersson et al 2007;Zhao et al 2012;Mu and Liao 2014).…”

“…Previous studies also showed that the interannual variations (IAVs) of aerosols were significant in the eastern US (Alston et al 2012), eastern China (Yang et al 2011;Mu and Liao 2014), and Europe (Andersson et al 2007). The IAVs in aerosol concentrations were found to be sensitive to the IAVs in anthropogenic emissions of aerosols and aerosol precursors (Mylona 1996;Irie 2005;Ohara et al 2007;Vestreng et al 2007;Xing et al 2013) and in meteorological conditions, since the meteorology modulates the processes of dilution, transport, deposition, and chemical reaction (Andersson et al 2007;Zhao et al 2012;Mu and Liao 2014).…”