摘要
Owing to uneven environmental monitoring site distribution,there are significant spatial data gaps for concentrations of ambientfine particles with diameters≤2.5µm(PM_(2.5))obtained using traditional monitoring methods.Satellite products are an alternative data source for locations where monitoring sites are unavailable.The Moderate Resolution Imaging Spectroradiometer(MODIS)aerosol optical depth(AOD)product has been widely used in PM_(2.5) assessment for years;however,it has obvious data gaps in winter.Here,the Visible Infrared Imaging Radiometer Suite(VIIRS)AOD was applied to supplement MODIS AOD data to obtain a fused AOD dataset.A three-stage model consisting of a corrected AOD model,mixed effects model,and geographically weighted regression model was developed and used with meteorological and vegetation factors to estimate PM_(2.5).Results showed overall modelfitting by cross-validation(CV)with an R^(2) of 0.92,mean absolute error of 5.72μg/m^(3),and root mean square error of 7.15μg/m^(3).The combination of MODIS AOD and VIIRS AOD was a suitable method for enhancing AOD coverage.The CV R^(2) value of the three-stage model(0.92)was higher than that of the two-stage model(0.9).Hence,the three-stage model could achieve a betterfit in estimating PM_(2.5) on a regional scale.
基金
supported by National Key Research and Development Program[grants number 2016YFC0201700].
