Teng, SW; Liu, C; Zhang, ZB; Wang, Y; Sohn, BJ; Yung, YL (2020). Retrieval of Ice-Over-Water Cloud Microphysical and Optical Properties Using Passive Radiometers. GEOPHYSICAL RESEARCH LETTERS, 47(16), e2020GL088941.

Current satellite cloud products from passive radiometers provide effective single-layer cloud properties by assuming a homogeneous cloud in a pixel, resulting in inevitable biases when multiple-layer clouds are present in a vertical column. We devise a novel method to retrieve cloud vertical properties for ice-over-water clouds using passive radiometers. Based on the absorptivity differences of liquid water and ice clouds at four shortwave-infrared channels (centered at 0.87, 1.61, 2.13, and 2.25 mu m), cloud optical thicknesses (COT) and effective radii of both upper-layer ice and lower-layer liquid water clouds are inferred simultaneously. The algorithm works most effectively for clouds with ice COT 5. The simulated spectral reflectances based on our retrieved ice-over-water clouds become more consistent with observations than those with a single-layer assumption. This new algorithm will improve our understanding of clouds, and we suggest that these four cloud channels should be all included in future satellite sensors.