AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Impact of Mixing State on Black Carbon Mass Absorption Cross Section
JIANDONG WANG, Shuxiao Wang, Jing Cai, Mei Zheng, Jingkun Jiang, Zhen Li, Runlong Cai, Tsinghua University
Abstract Number: 262 Working Group: Haze in China: Sources, Formation Mechanisms, and Current Challenges
Abstract The effects of black carbon (BC) on the Earth’s radiative balance remain a major uncertainty in climate models. Mass absorption cross section (MAC) is a key parameter for BC radiative effect, which characterizing the absorption properties of BC, and affected by the mixing state of BC with other particulate matter (PM) species. The purpose of this study is to investigate the effect of mixing state on MAC. The observation campaign was done in March 2015 in Peking University, Beijing, China. A suite of real-time instruments, including an Single particle aerosol mass spectrometer (SPAMS), a Scanning Mobility Particle Sizer (SMPS), a Photoacoustic Extinctiometer (PAX), a semi-continuous OC-EC analyzer, an Aerosol Chemical Speciation Monitor (ACSM), was employed to determine the MAC and PM mixing state. MAC is measured at 870 nm and varied from 4.3 m$^2g$^(-1) to 11.6 m$^2g$^(-1). The quantified mass concentration of each particle was determined by SPAMS and the calibrated by the results of SMPS, ACSM and semi-continuous OC-EC analyzer. The results show that MAC is positive correlated with OC mass concentration and negative correlated with EC mass concentration. The variation of MAE was found to coincide with the OC to EC ratio, perhaps due to the enhancement by coating. The results indicate that the mixing state of PM should be included in the optical calculation, especially in climate model.