Optical remote sensing of dense isolated clouds with high-resolution satellite- and ground-based imagers

Dense isolated (cumulus-type) clouds are not amenable to the standard plane-parallel slab geometry used in operational remote sensing. We show that their opacity can nonetheless be estimated using an alternate geometrical model - the spherical cloud - which is also analytically tractable for photon transport by diffusion. The new retrieval method is illustrated with a cloudy Multispectral Thermal Imager (MTI) scene but could be applied to ground-based sky imagers. The only requirement is to have both dark and bright sides of the cloud in the same scene. Future application to the development of correction schemes for cloud-adjacency effects is discussed.