Abstract: Cloud photographs are available from geosynchronous weather satellites at intervals of approximately 20 min. Sequences of such photographs show cloud motions over vast regions of the planet, providing a potential source of useful weather data, particularly over the oceans, since there are few weather-monitoring stations at sea. Our computer programs represent objective methods that require a minimum of human assistance to compute cloud motions. Computer algorithms are described for matching the earth's disk, giving a global registration; a more precise local registration is then achieved by matching landmarks. Accurate registration is needed because the satellite cannot be given an ideal synchronous orbit and perfect attitude stability. We have experimented with landmark templates of sizes 10×10 and 20×20 picture elements, representing 25-mi and 50-mi squares. An initial coarse scan of the template suggests where to try a succession of fine scans. The disk matching and the template matching are combined in the complete subsystem for registration. Properly registered cloud data are processed by means of the ISODATA clustering algorithm, which represents a cloud pattern by a number of cluster centers. Cloud motions are found by tracking these centers on successive pictures.

Abstract: An apparatus in which a cloud of toner particles is produced in a development zone for rendering viewable an electrostatic latent image. Subsequently, the unused toner particles are formed into a cloud of particles in a retrieval zone for return to the developer mix.

Abstract: This study is a part of NASA's continued program to provide global statistics of cloud parameters for computer simulation. The primary emphasis was on the development of the data bank of the global statistical distributions of cloud types and cloud layers and their applications in the simulation of the vertical distributions of in-cloud parameters such as liquid water content. These statistics were compiled from actual surface observations as recorded in Standard WBAN forms. Data for a total of 19 stations were obtained and reduced. These stations were selected to be representative of the 19 primary cloud climatological regions defined in previous studies of cloud statistics. Using the data compiled in this study, a limited study was conducted of the hemogeneity of cloud regions, the latitudinal dependence of cloud-type distributions, the dependence of these statistics on sample size, and other factors in the statistics which are of significance to the problem of simulation. The application of the statistics in cloud simulation was investigated. In particular, the inclusion of the new statistics in an expanded multi-step Monte Carlo simulation scheme is suggested and briefly outlined.