Possible effects of climate change of wind on aerosol variation during winter in Shanghai, China--颗粒学报PARTICUOLOGY

Zhou, W., Tie, X., Zhou, G., & Liang, P. (2015). Possible effects of climate change of wind on aerosol variation during winter in Shanghai, China. Particuology, 20, 80–88. https://doi.org/10.1016/j.partic.2014.08.008

Possible effects of climate change of wind on aerosol variation during winter in Shanghai, China

Weidong Zhou ^a, Xuexi Tie ^{b c *}, Guangqiang Zhou ^a, Ping Liang ^d

a Shanghai Center for Urban Environmental Meteorology, Shanghai 200135, China
b Key Laboratory of Aerosol Science and Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xian 710075, China
c National Center for Atmospheric Research, Boulder, CO 80307, USA
d Shanghai Climate Center, Shanghai 200030, China

10.1016/j.partic.2014.08.008

Volume 20, June 2015, Pages 80-88

Received 13 February 2014, Revised 12 August 2014, Accepted 13 August 2014, Available online 3 January 2015.

E-mail: xxtie@ucar.edu

Highlights

• Long-term change of aerosol density over Shanghai was investigated based on analysis of haze days.

• PM₁₀ concentration was in close relationship with wind direction and wind speed.

• A comprehensive wind factor was defined to reflect aggregate impact of wind conditions on aerosols.

• Atmospheric circulation was an important factor for change of wind direction and wind speed.

• Urbanization exerted great influences on diffusion condition of aerosols via impacting wind speed.

Abstract

Several data sets were introduced to investigate the possible effects of climate-change-related variation of wind on aerosol concentration during winter in Shanghai, China. These data sets included the daily wind speed, wind direction, visibility, and precipitation from 1956 to 2010, hourly PM₁₀ concentration from 2008 to 2010, and the NCEP/NCAR reanalysis data of global atmospheric circulation from 1956 to 2010. The trend of aerosol concentration and its correlations with wind speed and wind direction in winter were analyzed. Results indicated that there was an increase in the number of haze days in winter of 2.1 days/decade. Aerosol concentration, represented by PM₁₀ in this study, was highly correlated to both wind speed and direction in winter. The PM₁₀ concentration increased as wind speed decreased, reaching maximum values under static wind conditions. The PM₁₀ concentration was relatively lower under easterly winds and higher under westerly winds. The analysis showed that weaker East Asia winter monsoons have resulted in a reduction of wind speed, increase in static wind frequency, and decline in the frequency of northerly winds since the 1980s. Moreover, the rapid expansion of urban construction in Shanghai has changed the underlying surface considerably, which has led to a reduction in wind speed. Finally, a wind factor was defined to estimate the combined effects of wind speed and wind direction on aerosol concentrations in Shanghai. The analysis of this factor indicated that changes in atmosphere circulation and urbanization have had important effects on the number of winter haze days in Shanghai.

Graphical abstract

Keywords

Aerosol; Wind; Climate change; Winter monsoon; Shanghai

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