Quality, Compatibility and Synergy Analyses of Global Aerosol Products

Jeong, M.-J.(a), Li,Z.(a), Chu, A.(b), and Tsay, S.-C.(b), University of Maryland (a), NASA Goddard Space Flight Center (b)

Numerous global aerosol products have been generated with varying quality, strength and weakness. Presented here are synthetic analyses with regard to the quality, compatibility and synergy of three global aerosol products derived from the long-term (1983-2000) AVHRR and TOMS sensors, and the state-of-the-art MODIS sensor. Four essential aerosol parameters, namely, aerosol optical thickness (AOT) from all three sensors, Angstrom exponent (AE) from AVHRR and MODIS, and aerosol index (AI) from TOMS are analyzed together with various ancillary data sets such as cloud from ISCCP, wind vector from NCAR/NOAA reanalysis, ocean color from SeaWifs/CZCS, AERONET, etc. While the three products reveal some common features, significant discrepancies exist. Reflectances measured by different sensors show significant in-compatibility in that AE computed from their combinations exceeds the normal ranges associated with the spectral discrepancies of the channels. The three products are complimentary in revealing different aspects of aerosol characteristics. Both under- and over-estimation of AOT were found that are attributed to cloud contamination and misclassification of heavy aerosol episodes as clouds, respectively. In-depth analyses were carried over several regions under the influence of different types of aerosols such as biomass burning, dust, sea-salt, air-pollution and their mixtures. Some interesting findings were obtained. A synergy algorithm was developed to identify dominant types of aerosols around the globe using aerosol products from the combination of the TOMS and AVHRR aerosol products, which is used to generate a merged global aerosol product over both oceans and land at 0.55mm. Comparisons against AERONET data showed good agreements. Inherent discrepancies in retrieved AOT from MODIS and AVHRR are evaluated in terms of differences of the aerosol models employed by the two different algorithms.

Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).