Inferring Polluted Asian Absorbing Aerosol Properties Using Decadal Scale AERONET Measurements and a MIE Model

Abstract

Aerosol has been identified as one of the largest contributors to the uncertainty in our understanding of a diverse set of environmental issues including: the earth's radiation balance and climate change (Chung &

Aloft Transport of Haze Aerosols to Xuzhou, Eastern China: Optical Properties, Sources, Type, and Components

“…Using the sunphotometer measurements from 1 December 2014 to 10 January 2015, a comparison of the days showing aerosol layers aloft against those days without aerosols aloft, in terms of mean values and standard deviations of AOD at 500 nm, AE, and FMF (fine mode fraction), is made. All three parameters are observed to be larger when an aloft haze plume is present, suggesting high aerosol loadings and smaller particles, again consistent with urban sources [56].…”

“…Using the sunphotometer measurements from 1 December 2014 to 10 January 2015, a comparison of the days showing aerosol layers aloft against those days without aerosols aloft, in terms of mean values and standard deviations of AOD at 500 nm, AE, and FMF (fine mode fraction), is made. All three parameters are observed to be larger when an aloft haze plume is present, suggesting high aerosol loadings and smaller particles, again consistent with urban sources [56]. Figure 4 shows the AE (440-870 nm) and the AOD (440, 675, 870, and 1020 nm) (a,b), the absorption aerosol optical depth (AAOD) (at 440, 675, 870, and 1020 nm) (c,d), and the SSA (440, 675, 870, and 1020 nm) (e,f) during the aloft-haze-plume events.…”

Remotely Sensed Top-Down Derived Daily BC Over Rapidly Changing Western China shows Significant Decreases in Mass Due to Policy Action, Coupled with Inconsistent Changes in Number, Size, and Mixing Properties

“…This work assumes that all particles have a core-shell structure, which has been shown to be reasonable in urban areas of Asia. Absorptive aerosols are assumed to contain a core (BC) and a scattering coating (sulphate) 47,79 , where the core refractive index (2.0 + 1.0i) 91 and the shell refractive index (1.52-5×10 − 4 i) 92 , the particle size and refractive index are used to nd the corresponding core-shell and mixed-state probability distributions of the particulate matter by extinction e ciency (Qext), scattering e ciency (Qsca) and absorption e ciency (Qabs), and hence the corresponding single scattering albedo (SSA), among others, based on the calculated SSA. This is physically consistent with the fact that many of the primary aerosols in these areas are organic and the fact that they age rapidly in situ over time.…”

“…The MIE model calculations used all available SSA observations at each individual wavelength which fall between the respective 5-year tting window's 10th to 90th percentile. Probability distributions for each set of solutions over reach region and subcategory as mentioned above are computed, and the union of all possible soltions is the true range used hereafter following Wang et al 79 and Wang et al 80 . Based on the results of the probabilistic range of computed core and shell mixtures, the distribution of per particle aborbtion (Qabs) is computed.…”

“…These non-biased regions ad then sampled over two decades using observations of AOD, AAOD, and SSA exclusively from the MISR satellite 68,73-77 over areas which have not been previously studied in central and northwestern China, but which have undergone a tremendous amount of change in urbanization and energy consumption over the past two decade 78 . The observations are analyzed in a new way, using an inversely applied MIE modeling approach to constrain the per particle mixing state and particle size [79][80][81][82][83] based on the multiple independent observations made by MISR across different wavebads 84,85 . The resulting properties per particle are then used to compute the atmospheric loading of mass and number, and provide an independent way to consistent analyze the emissions and impcats that aersoosl have, and to open a new approach forward that the global aerosol and climate communities can adapt to further advance the community's ability to better constrain the aerosol uncertainties on climate and the environmet.…”