The spatial coherence method for obtaining fractional cloud cover from satellite imagery is extended to the case of multilayered cloud systems. Examples are presented in which simultaneous observations at 3.7 μm and 11 μm are used to solve a system of linear equations for the nonoverlapped fractional cover contributed by each of two layers. The retrieval relies on the assumption that the clouds reside in distinct, well-defined layers and are optically thick at the wavelengths of observation. Simultaneous observations at 3.7 μm and 11 μm of the separate layers indicate that the assumptions are generally valid. Owing to the reflection of solar radiation at 3.7 μm by low-level water clouds, the method is limited to nighttime observations. |