An advanced synergetic algorithm for aerosol optical depth retrieval from HJ-1A HSI and Terra MODIS data based on mutual information

In this paper, an advanced synergetic algorithm for aerosol retrieval from small satellite data is presented and applied on MODerate resolution Imaging Spectroradiometer (MODIS) and the Hyper-Spectral Imager (HSI) data from China HJ-1A satellite of the Environment and Disasters Monitoring Micro satellite Constellation. Using this algorithm, 500m MODIS data are downscaled to 100m based on maximal mutual information. By synergy of MODIS and HJ-1A HSI data, we obtained 100m × 100m aerosol optical depth (AOD) at 550nm over Beijing City, on April 5, 2009. Comparison with Aerosol Robotic Network (AERONET) measurement data, our results have good precision. The correlation coefficient is about 0.86 and the uncertainty is found to be Δτ = ±0.01 ± 0.23τ. From 100m AOD map, we can see more details of aerosols´ spatial distribution. It is very useful and powerful for urban air quality monitoring.