title: Improving the accuracy of daily satellite-derived ground-level fine aerosol concentration estimates for North America.
abstract: We improve the accuracy of daily ground-level fine particulate matter concentrations (PM(2.5)) derived from satellite observations (MODIS and MISR) of aerosol optical depth (AOD) and chemical transport model (GEOS-Chem) calculations of the relationship between AOD and PM(2.5). This improvement is achieved by (1) applying climatological ground-based regional bias-correction factors based upon comparison with in situ PM(2.5), and (2) applying spatial smoothing to reduce random uncertainty and extend coverage. Initial daily 1-σ mean uncertainties are reduced across the United States and southern Canada from ± (1 μg/m(3) + 67%) to ± (1 μg/m(3) + 54%) by applying the climatological ground-based regional scaling factors. Spatial interpolation increases the coverage of satellite-derived PM(2.5) estimates without increased uncertainty when in close proximity to direct AOD retrievals. Spatial smoothing further reduces the daily 1-σ uncertainty to ±(1 μg/m(3) + 42%) by limiting the random component of uncertainty. We additionally find similar performance for climatological relationships of AOD to PM(2.5) as compared to day-specific relationships.
authors.affiliation: Dept. of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada. Aaron.van.Donkelaar@dal.ca
authors.forename: Aaron
authors.initials: A
authors.lastname: van Donkelaar
authors.forename: Randall V
authors.initials: RV
authors.lastname: Martin
authors.forename: Adam N
authors.initials: AN
authors.lastname: Pasch
authors.forename: James J
authors.initials: JJ
authors.lastname: Szykman
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Yuxuan X
authors.initials: YX
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Chen
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data; D008962:Models, Theoretical; D009656:North America; D052638:Particulate Matter / Q000032:analysis*; D017215:Satellite Communications; D035501:Uncertainty
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter