Abstract

Ground-based characteristics (optical, type, size, and radiative properties) of aerosols measured between 2005 and 2012 were investigated over the Taihu rim region, which encompasses the cities of Shanghai, Suzhou, Wuxi, and Changzhou. The aerosol optical depth (AOD) showed a distinct seasonal variation with the highest value in summer and the lowest AOD in winter. There was broadest frequency distribution with a multimodal structure in summer. The Ångström exponent (AE) showed high values during spring; the relative frequency of AE in the range of 0–0.8 was 5–10 times greater than that of other seasons. The samples with high ${\mathrm{AOD}}_{440}$ and low ${\mathrm{AE}}_{440-870}$ were mainly observed in spring, which is attributed to the relative abundance of coarse particles. The monthly aerosol volume size distributions presented a bimodal structure (fine and coarse modes). The coarse mode was dominant during spring, while the fine mode was predominant in other seasons. The main aerosol type over Taihu during all the seasons was the mixed small-particle category, followed by the urban/industrial category. The minimum single scattering albedo (SSA) occurred in winter, suggesting that atmosphere aerosol had a higher absorption. All monthly averaged asymmetry factors (ASY) had positive values and no distinct seasonal variation. Both high real (Re) and imaginary (Im) parts of the refractive index occurred in winter. The atmospheric warming effect of aerosol was more significant in winter compared with other seasons, with the averaged atmosphere aerosol radiative forcing (ARF) and the corresponding atmospheric heating rate up to $+69.46\mathrm{W}·{\mathrm{m}}^{-2}$ and $1.95\mathrm{K}·{\text{day}}^{-1}$, respectively. There existed a significant positive correlation between AOD and ARF (absolute value), and the correlation coefficients ($r$) exceeded 0.86 in each season with maximum $r$ in summer. Along with the increasing of the SSA, the aerosol radiative forcing efficiency (absolute value) showed a decreasing trend at the bottom of the atmosphere and an increasing trend at the top of the atmosphere.

© 2017 Optical Society of America

Characterization of aerosol optical properties using multiple clustering techniques over Zanjan, Iran, during 2010–2013

Maryam Gharibzadeh, Khan Alam, Yousefali Abedini, Abbasali Aliakbari Bidokhti, Amir Masoumi, and Humera Bibi
Appl. Opt. 57(11) 2881-2889 (2018)

Long-term (2007–2013) analysis of aerosol optical properties over four locations in the Indo-Gangetic plains

Humera Bibi, Khan Alam, Thomas Blaschke, Samina Bibi, and Muhammad Jawed Iqbal
Appl. Opt. 55(23) 6199-6211 (2016)

Light-absorbing aerosol properties retrieved from the sunphotometer observation over the Yangtze River Delta, China

Jing Wang, Shengjie Niu, and Dan Xu
Appl. Opt. 57(5) 992-1004 (2018)

Aerosol optical properties and precipitable water vapor column in the atmosphere of Norway

Dennis Muyimbwa, Øyvind Frette, Jakob J. Stamnes, Taddeo Ssenyonga, Yi-Chun Chen, and Børge Hamre
Appl. Opt. 54(6) 1505-1514 (2015)

Retrieval of the aerosol asymmetry factor from Sun–sky radiometer measurements: application to almucantar geometry and accuracy assessment

Lili Qie, Zhengqiang Li, Philippe Goloub, Li Li, Donghui Li, Kaitao Li, Ying Zhang, and Hua Xu
Appl. Opt. 56(36) 9932-9940 (2017)