Seasonal variation of columnar aerosol optical properties in Yangtze River Delta in China

Aerosols played an important role in climate change during recent years in China. Many kinds of researches in different areas in China, particularly over the Yangtze River Delta (YRD) region in East China is measured during the period from January 2013 to December 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol optical depth (AOD), particulate matter concentrations (PM2.5) and surface black carbon (BCS) was used in this study. Nanjing, Hangzhou, Shanghai, and Ningbo have been selected in this research as they are the major cities of the YRD region that represents different environments. Variation of AOD550, Ångström exponent (AE470-660) and PM2.5 are mainly discussed, and meanwhile, the relationship that exists between them and with the meteorology is also discussed in this work. Apart from this, the impact of visibility and water vapor are also considered to examine the influence on optical properties. The data and analysis indicate that urban cities have a higher value of AOD than rural background cities. High AOD was noticed in summer than in other seasons. AOD usually has a negative relationship with AE, except in summer. Similarly, the PM2.5 has a negative relationship with AOD, whereas, BCS has a positive correlation with AOD. Further, it was observed that the rise in temperature resulted in high AOD concentration. The visibility has negative effect on AOD, whereas, AQI follows similar pattern as that of visibility.

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Seasonal variation of urban carbonaceous aerosols in a typical city Nanjing in Yangtze River Delta, China

Atmospheric Environment ◽

10.1016/j.atmosenv.2015.01.064 ◽

2015 ◽

Vol 106 ◽

pp. 223-231 ◽

Cited By ~ 57

Author(s):

Bing Li ◽

Jie Zhang ◽

Yu Zhao ◽

Siyu Yuan ◽

Qiuyue Zhao ◽

...

Keyword(s):

Seasonal Variation ◽

Yangtze River ◽

Yangtze River Delta ◽

River Delta ◽

Carbonaceous Aerosols

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The optical properties, physical properties and direct radiative forcing of urban columnar aerosols in the Yangtze River Delta, China

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-1419-2018 ◽

2018 ◽

Vol 18 (2) ◽

pp. 1419-1436 ◽

Cited By ~ 9

Author(s):

Bingliang Zhuang ◽

Tijian Wang ◽

Jane Liu ◽

Huizheng Che ◽

Yong Han ◽

...

Keyword(s):

Optical Properties ◽

Physical Properties ◽

Yangtze River ◽

Eastern China ◽

Yangtze River Delta ◽

River Delta ◽

Transfer Model ◽

Size Distributions ◽

Haze Pollution ◽

The Yrd

Abstract. The optical and physical properties as well as the direct radiative forcings (DRFs) of fractionated aerosols in the urban area of the western Yangtze River Delta (YRD) are investigated with measurements from a Cimel sun photometer combined with a radiation transfer model. Ground-based observations of aerosols have much higher temporal resolutions than satellite retrievals. An initial analysis reveals the characteristics of the optical properties of different types of fractionated aerosols in the western YRD. The total aerosols, mostly composed of scattering components (93.8 %), have mean optical depths of 0.65 at 550 nm and refractive index of 1.44 + 0.0084i at 440 nm. The fine aerosols are approximately four times more abundant and have very different compositions from coarse aerosols. The absorbing components account for only ∼  4.6 % of fine aerosols and 15.5 % of coarse aerosols and have smaller sizes than the scattering aerosols within the same mode. Therefore, fine particles have stronger scattering than coarse ones, simultaneously reflecting the different size distributions between the absorbing and scattering aerosols. The relationships among the optical properties quantify the aerosol mixing and imply that approximately 15 and 27.5 % of the total occurrences result in dust- and black-carbon-dominating mixing aerosols, respectively, in the western YRD. Unlike the optical properties, the size distributions of aerosols in the western YRD are similar to those found at other sites over eastern China on a climatological scale, peaking at radii of 0.148 and 2.94 µm. However, further analysis reveals that the coarse-dominated particles can also lead to severe haze pollution over the YRD. Observation-based estimations indicate that both fine and coarse aerosols in the western YRD exert negative DRFs, and this is especially true for fine aerosols (−11.17 W m−2 at the top of atmosphere, TOA). A higher absorption fraction leads directly to the negative DRF being further offset for coarse aerosols (−0.33 W m−2) at the TOA. Similarly, the coarse-mode DRF contributes to only 13.3 % of the total scattering aerosols but > 33.7 % to the total absorbing aerosols. A sensitivity analysis states that aerosol DRFs are not highly sensitive to their profiles in clear-sky conditions. Most of the aerosol properties and DRFs have substantial seasonality in the western YRD. The results further reveal the contributions of each component of the different size particles to the total aerosol optical depths (AODs) and DRFs. Additionally, these results can be used to improve aerosol modelling performance and the modelling of aerosol effects in the eastern regions of China.

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