查看文章

The Moderate Resolution Imaging Spectroradiometer (MODIS) cloud product provides three separate 1 km resolution retrievals of cloud particle effective radii (r_e), derived from 1.6, 2.1 and 3.7 μm band observations. In this study, differences among the three size retrievals for maritime water clouds (designated as r_e,1.6r_e,2.1 and r_e,3.7) were systematically investigated through a series of case studies and global analyses. Substantial differences are found between r_e,3.7 and r_e,2.1 retrievals (Δr_e,3.7–2.1), with a strong dependence on cloud regime. The differences are typically small, within ±2 μm, over relatively spatially homogeneous costal stratocumulus cloud regions. However, for trade wind cumulus regimes, r_e,3.7 was found to be substantially smaller than r_e,2.1, sometimes by more than 10 μm. The correlation of Δr_e,3.7–2.1 with key cloud parameters, including the cloud optical thickness (τ), r_e and a cloud …