Comparison between MODIS aerosol product C004 and C005 and evaluation of their applicability in the north of China
MODIS气溶胶C004、C005产品的对比分析及其在中国北方地区的适用性评价

MODIS aerosol product Collection 005 (C005) is an upgrade of C004, and is introduced in detail in this paper. Through fitting with AERONET ground observation aerosol optical thickness (AOT), MODIS aerosol C004 and C005 products of TERRA and AQUA are compared and evaluated to analyze their applicability in the north of China at Beijing and Yulin sites. We match AERONET ground-based data with MODIS aerosol product by band interpolation and temporal-spatial matching, then compare and evaluate them by linear fitting. We conceive a scale of temporal-spatial matching in the north of China considering the local aerosol movement velocity of given sites. The results show that: (1) C005 product algorithm does not improve the accuracy of AOT at Beijing site, and the accuracy drops when AOT< 0.8; both C004 and C005 products do not have a significant application at Beijing site, but the C004 performs better than C005 products. (2) At Yulin site, TERRA-MODIS C004 product meets the demand, and the accuracy of AQUA-MODIS C004 product decreases. Compared with the C004 product, the accuracy of the C005 product improves greatly, and correlation coefficients between AOTs of three bands (470nm, 550nm, 660nm) and the AERONET ground observation data are all higher than 0.9. It could be concluded that the method of the surface reflectance determination used in the new algorithm is feasible for dark dense vegetation, but is not suitable for the bright surface.