Seasonal variation and difference of aerosol optical properties in columnar and surface atmospheres over Shanghai

Cheng, Tiantao; Xu, Chen; Duan, Jingxian; Wang, Yifan; Leng, Chunpeng; Tao, Jun; Che, Huizheng; He, Qianshan; Wu, Yunfei; Zhang, Renjian; Li, Xiang; Chen, Jianmin; Kong, Lingdong; Yu, Xiangyao

doi:10.1016/j.atmosenv.2015.05.029

Cited by 81 publications

(57 citation statements)

References 80 publications

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“…Average PM 2.5 / PM 10 mass ratios ranged from 0.41 to 0.93 with an average of 0.68 ± 0.1. σ s at 550 nm ranged from 12.7 to 678.4 Mm −1 with an average of 189.1 ± 142.0 Mm −1 . The average σ s in this study is comparable with the annual mean of 217 Mm −1 measured in the Shanghai region, China, during 2010-2012 (Cheng et al, 2015) but is lower than the annual mean of 360 Mm −1 in the Beijing region, China, mea-sured during (Jing et al, 2015. Because light scattering is caused mainly by aerosol particles and the scattering measurements of the present study were performed under dry conditions (RH < 30 %), similar temporal patterns were observed for PM mass and σ s (Fig.…”

Section: Satellite Rgb (Red Green Blue) Images and Air Mass Backwarsupporting

confidence: 65%

“…The ω measured by ground-based remote sensing (0.9-0.93) is ∼ 10 % higher than values measured at the surface (0.8-0.9) (Cheng et al, 2015). From one year's worth of observations in Seoul, South Korea, a trend of increasing ω with wavelength was observed during Asian dust events, whereas little spectral dependence of ω was observed during LRT haze events (Jung et al, 2010).…”

Section: Introductionmentioning

confidence: 94%

“…In addition to anthropogenic pollutants, Asian dust originating from major deserts located in northern and western parts of China (e.g., the Gobi desert and Taklimakan desert) influences the air quality of China (Bi et al, 2016;Li et al, 2016). Asian dust has a high light scattering property (single scattering albedo, ω at 550 nm = 0.935) and a low wavelength dependence of optical properties (Ångström exponent, Å at 440-870 nm = ∼ 0.2) (Bi et al, 2016), whereas anthropogenic pollutants from megacities in China have relatively high light-absorbing properties (ω at 532 nm = 0.82 (Guangzhou), 0.86 (Beijing), 0.83 (Shanghai)) and strong wavelength dependence (Å at 450-700 nm = 1.46 (Guangzhou), 1.42 (Beijing)) (Garland et al, 2008(Garland et al, , 2009Cheng et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Ground-based characterization of aerosol spectral optical properties of haze and Asian dust episodes under Asian continental outflow during winter 2014

Jung

Yu²,

Lyu³

et al. 2017

Atmos. Chem. Phys.

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Abstract. Long-range transported (LRT) haze can affect the regional radiation budget and the air quality in areas downwind of the Asian continental outflow. Because in situ observations of spectral aerosol optical properties of the LRT haze are rare, an intensive characterization of aerosol optical properties is needed. This study characterized the spectral optical properties of the LRT haze and Asian dust originating from the Asian continent. Integrated chemical and optical measurements of aerosol particles were carried out in a downwind area of the Asian continental outflow (Daejeon, South Korea) during winter 2014. High concentrations of PM 10 (particulate matter with a diameter ≤ 10 µm) and light scattering coefficients at 550 nm, σ s,550 , were observed during a long-range transport (LRT) haze episode (PM 10 = 163.9 ± 25.0 µg m −3 ; σ s,550 = 503.4 ± 60.5 Mm −1 ) and Asian dust episode (PM 10 = 211.3 ± 57.5 µg m −3 ; σ s,550 = 560.9 ± 151 Mm −1 ). During the LRT haze episode, no significant change in the relative contribution of PM 2.5 (particulate matter with a diameter ≤ 2.5 µm) chemical components was observed as particles accumulated under stagnant atmospheric conditions (13-17 January 2014), suggesting that the increase in PM 2.5 mass concentration was caused mainly by the accumulation of LRT pollutants. On the other hand, a gradual decrease in Ångström exponent (Å) and a gradual increase in single scattering albedo (ω) and mass scattering efficiency (MSE) were observed during the stagnant period, possibly due to an increase in particle size. These results imply that a change in particle size rather than chemical composition during the stagnant period is the dominant factor affecting the aerosol optical properties. During the Asian dust episode, a low PM 2.5 / PM 10 ratio and Å(450/700) were observed with average values of 0.59 ± 0.06 and 1.08 ± 0.14, respectively, which were higher than those during the LRT haze episode (0.75 ± 0.06 and 1.39 ± 0.05, respectively), indicating that PM 2.5 / PM 10 mass ratios and Å(450/700) can be used as tracers to distinguish aged LRT haze and Asian dust under the Asian continental outflow.

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Section: Satellite Rgb (Red Green Blue) Images and Air Mass Backwarsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ground-based characterization of aerosol spectral optical properties of haze and Asian dust episodes under Asian continental outflow during winter 2014

Jung

Yu²,

Lyu³

et al. 2017

Atmos. Chem. Phys.

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“…Studies of aerosol optical properties in eastern China have contributed to our understanding of local air quality and regional climate impacts (Duan and Mao, 2007;Pan et al, 2010;Ding et al, 2016). In the YRD, investigations of aerosol optical properties have been conducted in Nanjing, Hefei, Shanghai, Shouxian and Taihu (Zhuang et al, 2014;He et al, 2012; K. H. Cheng et al, 2015;Xia et al, 2007). Those studies mostly involved sampling at single sites ∼ 100 km apart from one other without synchronous observations, and many have been of relatively short duration, and so there remains a need for more extensive ground-based measurements.…”

Section: Introductionmentioning

confidence: 99%

“…Those sites typically have had high aerosol loadings and in many cases serious environmental problems (Cheng et al, 2015;Pan et al, 2010;Xia et al, 2013; L. C. ; H. Z. . Detailed information on aerosol optical depth (AOD), the types of aerosols and especially the size and absorption properties of ambient populations over a wide sampling of regions is needed to understand the effects of aerosols on the Earth's climate and the environment (Giles et al, 2011;Wang et al, 2010;.…”

Section: Introductionmentioning

confidence: 99%

Aerosol optical properties and direct radiative forcing based on measurements from the China Aerosol Remote Sensing Network (CARSNET) in eastern China

et al. 2018

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Abstract. Aerosol pollution in eastern China is an unfortunate consequence of the region's rapid economic and industrial growth. Here, sun photometer measurements from seven sites in the Yangtze River Delta (YRD) from 2011 to 2015 were used to characterize the climatology of aerosol microphysical and optical properties, calculate direct aerosol radiative forcing (DARF) and classify the aerosols based on size and absorption. Bimodal size distributions were found throughout the year, but larger volumes and effective radii of fine-mode particles occurred in June and September due to hygroscopic growth and/or cloud processing. Increases in the fine-mode particles in June and September caused AOD 440 nm > 1.00 at most sites, and annual mean AOD 440 nm values of 0.71-0.76 were found at the urban sites and 0.68 at the rural site. Unlike northern China, the AOD 440 nm was lower in July and August (∼ 0.40-0.60) than in January and February (0.71-0.89) due to particle dispersion associated with subtropical anticyclones in summer. Low volumes and large bandwidths of both fine-mode and coarsemode aerosol size distributions occurred in July and August because of biomass burning. Single-scattering albedos at 440 nm (SSA 440 nm ) from 0.91 to 0.94 indicated particles with relatively strong to moderate absorption. Strongly absorbing particles from biomass burning with a significant SSA wavelength dependence were found in July and August at most sites, while coarse particles in March to May were Published by Copernicus Publications on behalf of the European Geosciences Union. 406H. Che et al.: Aerosol optical properties and direct radiative forcing mineral dust. Absorbing aerosols were distributed more or less homogeneously throughout the region with absorption aerosol optical depths at 440 nm ∼ 0.04-0.06, but inter-site differences in the absorption Angström exponent indicate a degree of spatial heterogeneity in particle composition. The annual mean DARF was −93 ± 44 to −79 ± 39 W m −2 at the Earth's surface and ∼ −40 W m −2 at the top of the atmosphere (for the solar zenith angle range of 50 to 80 • ) under cloud-free conditions. The fine mode composed a major contribution of the absorbing particles in the classification scheme based on SSA, fine-mode fraction and extinction Angström exponent. This study contributes to our understanding of aerosols and regional climate/air quality, and the results will be useful for validating satellite retrievals and for improving climate models and remote sensing algorithms.

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Classification of key aerosol types and their frequency distributions based on satellite remote sensing data at an industrially polluted city in the Yangtze River Delta, China

Kumar

Yin

2017

Intl Journal of Climatology

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ABSTRACT:In the present study, characterization of columnar aerosol optical properties and classifying the major aerosol types was investigated at an urban-industrial city, Nanjing in the Yangtze River Delta (YRD) region over East China using simultaneous data sets retrieved from the MODerate resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI) sensors during [2004][2005][2006][2007][2008][2009][2010][2011][2012][2013][2014][2015]. A notable spatiotemporal heterogeneity was observed in the optical properties of aerosols on the seasonal scale over East China. Aerosol optical depth at 550 nm (AOD 550 ) exhibited pronounced seasonal variability over Nanjing in the YRD, with higher values during summer and spring seasons and lower in winter. Ångström exponent (AE 470-660 ) found higher in summer indicating the relative abundance of fine mode aerosols over the coarse mode. We also used the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model for presenting cluster trajectory analysis which revealed that the airmasses from different source regions contributed greatly to aerosol loading during the study period. In addition, we followed two techniques for studying classification of major aerosol types based on the predefined thresholds. Using the AOD-AE method (here called as Technique-I), five major aerosol types were identified via, continental clean (CC), marine (MA), biomass burning/urban-industrial (BU), desert dust (DD), and mixed (MX). In all the seasons, MX is the dominant aerosol type followed by the BU and DD type aerosols during summer and spring seasons, respectively. Further, the sub-classification of aerosol types was carried out considering into account of the characteristics of absorbing aerosol index (AAI) (here called as Technique-II). The two clustering techniques showed reasonable consistency in the obtained results. The various aerosol types (absorbing and non-absorbing) and their change over a region are highly helpful in fine tuning the models to decrease the uncertainty in the radiative and climatic effects of aerosols.

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Seasonal variation and difference of aerosol optical properties in columnar and surface atmospheres over Shanghai

Cited by 81 publications

References 80 publications

Ground-based characterization of aerosol spectral optical properties of haze and Asian dust episodes under Asian continental outflow during winter 2014

Ground-based characterization of aerosol spectral optical properties of haze and Asian dust episodes under Asian continental outflow during winter 2014

Aerosol optical properties and direct radiative forcing based on measurements from the China Aerosol Remote Sensing Network (CARSNET) in eastern China

Classification of key aerosol types and their frequency distributions based on satellite remote sensing data at an industrially polluted city in the Yangtze River Delta, China

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