资源环境科技发展态势分析平台

The AE(AOD)- Delta AE(AOD) grid proposed by Gobbi et al. (2007) is a graphical method used to visually represent the spectral characterization of aerosol optical depth (AOD), i.e. Angstrom exponent (AE) and its curvature, in order to infer the fine mode contribution (eta) to the total AOD and the size of the fine mode aerosol particles. Perrone et al. (2014) applied this method for the wavelengths widely used in lidar measurements. However, in neither case does the method allow for a direct relationship between eta and the fine mode fraction contribution to the total aerosol population. Some discussions are made regarding the effect of shape and composition to the classical AE-Delta AE plot. The potential use of particle backscatter measurements, widely used in aerosol characterization methods together with extinction measurements, is also discussed in the AE-Delta AE grid context. A modification is proposed that yields the submicron contribution to the total volume concentration by using particle extinction data, and a comparison to experimental measurements is made. Our results indicate that the use of a modified AE-Delta AE grid plot to directly obtain submicrometric and micrometric mode fraction to the total aerosol population is feasible if a volume-based bimodal particle size distribution is used instead of a number-based one.