资源环境科技发展态势分析平台

This is a reply to the comment of Peng and Bi (2019) on the paper of Li et al. (2018, https://doi. org/10.1029/2018JD028956), which introduced a method to estimate aerosol effective density (rho(e)) based on a joint use of measurements of the scanning mobility particle sizer (SMPS) and the aerodynamic particle sizer (APS). In this reply, we describe the extension of the Cunningham slip correction factor (C-c) to the expression of the rho(e) and analyzed the useful but incomplete expression of rho(e) equation on C-c in Peng and Bi (2019) resulting from neglecting aerodynamic diameter. Meanwhile, in order to estimate C-c-related error on rho(e), Peng and Bi (2019) used an unreasonable scheme and an overestimated shape factor, which leads to a large overestimation (55.5%) of the error. We modify the error budget scheme and perform a theoretical error analysis on neglecting C-c during the.e measurement in practice. The results suggest an average bias of 17.68% on rho(e) resulting from C-c. Together with other error sources presented in Li et al. (2018, https://doi.org/ 10.1029/2018JD028956), the typical uncertainty on rho(e) based on this "SMPS-APS" joint-use method is 21.06%, which is still reasonable in practice.