DERIVING AN AEROSOL OPTICAL DEPTH CLIMATOLOGY OVER LAND USING AVHRR

摘要

Retrieval of aerosol optical depth (AOD) over land from satellite platforms has been limited in comparison to the number of retrievals over oceanic areas. Significantly, the NOAA Advanced Very High Resolution Radiometer (AVHRR) has provided nearly 20 years of AOD retrievals over the oceans with no corresponding retrieval over land. This retrieval gap is primarily due to uncertainties in the surface reflecting properties limiting retrieval performance. However, the length of AVHRR observations allows this variation to be deduced, leaving a residual which we hypothesize is an aerosol signal. First, the aerosol signal is estimated by removing surface and Rayleigh scattering effects. Then this proposed aerosol signal is compared to ground measurements of AOD. Results suggest that this aerosol signal is present and could be used to retrieve AOD over some land regions.