ort the development of electro/optical sensor systems under the Smart Weapons Operability Enhancement (SWOE) Program. TASC has developed a four-dimensional (3 spatial and 1 temporal) cloud model for use in radiometric computations and scene simulation. The cloud scene simulation model employs a multi-step process to generate the density fields beginning with the rescale and add fractional Brownian motion algorithm to simulate the horizontal distribution of cloud elements within the user-defined cloud domain. Knowledge of structures of stratiform and cirriform cloud types is used to specify the vertical extent of individual clouds. Internal variability is then generated within each cloud using a three-dimensional version of the rescale and add model. A physics-based scheme that models clouds as the sum of a large number of individual Lagrangian 'parcels' is used to simulate cumulus cloud growth and convection based on environmental conditions. In this paper we present a description of the cloud scene simulation modeling process. In particular, we emphasize the cumulus model which marries fractal field generation and convection dynamics to result in a computationally efficient method to generate cloud fields that are both physically derived and visually realistic.
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