Comparison of Experimental and Modeled Absorption Enhancement by Black Carbon (BC) Cored Polydisperse Aerosols under Hygroscopic Conditions
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- 作者：P. M. Shamjad ; S. N. Tripathi ; S. G. Aggarwal ; S. K. Mishra ; Manish Joshi ; Arshad Khan ; B. K. Sapra ; Kirpa Ram
- 刊名：Environmental Science & Technology (ES&T)
- 出版年：2012
- 出版时间：August 7, 2012
- 年：2012
- 卷：46
- 期：15
- 页码：8082-8089
- 全文大小：393K
- 年卷期：v.46,no.15(August 7, 2012)
- ISSN：1520-5851
文摘
The quantification of the radiative impacts of light absorbing ambient black carbon (BC) particles strongly depends on accurate measurements of BC mass concentration and absorption coefficient (尾abs). In this study, an experiment has been conducted to quantify the influence of hygroscopic growth of ambient particles on light absorption. Using the hygroscopic growth factor (i.e., Zdanovskii鈥揝tokes鈥揜obinson (ZSR) approach), a model has been developed to predict the chemical composition of particles based on measurements, and the absorption and scattering coefficients are derived using a core鈥搒hell assumption with light extinction estimates based on Mie theory. The estimated optical properties agree within 7% for absorption coefficient and 30% for scattering coefficient with that of measured values. The enhancement of absorption is found to vary according to the thickness of the shell and BC mass, with a maximum of 2.3 for a shell thickness of 18 nm for the particles. The findings of this study underline the importance of considering aerosol-mixing states while calculating their radiative forcing.