Multi-spatial Scale Aerosol Optical Thickness Mapping for Beijing Using Remote Sensing Technique

Aerosol particles play an important role in many atmospheric processes and affect global energy budget since they absorb and scatter solar radiation. In addition, aerosol particles take part in many heterogeneous chemical reactions and have adverse effects on human health. Retrieval of aerosol optical thickness (AOT) over bright land is still a challenging and imperative problem due to the complexity added by the variability of the land surface characteristics. In this paper, multi-spatial scale aerosol optical thickness mapping for Beijing was made using MODIS and ASTER data. The spatial resolution of aerosol optical thickness products are 15m, 250m, 500m, 1km and 10km, respectively. To retrieve AOT from MODIS data, the synergy of Terra and Aqua MODIS data algorithm and BRDF models were used. The BRDF characteristics of ground surfaces are considered by combining the geometrical information of solar and sensors extracted from MODIS data and linear kernel-driven BRDF parameter products (MOD43). An operation bi-angle approach was used to retrieve AOT from ASTER data. Validation is performed by comparison with AERONET (Aerosol Robtic Network) ground-based Sun-photometer data and the MODIS aerosol products (MOD04). Results show that the primary trend of AOT distribution for different spatial scales over the same region is consistent. When zoom in to details, the distribution of AOT are different between multi-spatial scales. ∗ Corresponding author