Abstract
Space and time autocorrelation functions are defined for the precipitation process on a horizontal plane. An optical device was designed and used to measure these functions as well as the mean, the mean square, and the variance of the rainfall rate for a time sequence of precipitation patterns of a widespread convective storm. The input data were radar PPI records stored on film in which the transmittance was adjusted to be proportional to rainfall rate. Abstract Space and time autocorrelation functions are defined for the precipitation process on a horizontal plane. An optical device was designed and used to measure these functions as well as the mean, the mean square, and the variance of the rainfall rate for a time sequence of precipitation patterns of a widespread convective storm. The input data were radar PPI records stored on film in which the transmittance was adjusted to be proportional to rainfall rate.