Bistatic Radar Observations of Drop Size Distribution in a Rain Shower

摘要

Simultaneous measurements of the orthogonal components of the signal scattered out of the beam of a vertically looking radar were measured. Two-parameter drop size distribution functions, such as that proposed by Marshall and Palmer, were inferred from the measured data. Drop size distributions were measured at the ground using a drop size distribution meter (disdrometer) for two rain showers. A comparison was made between the radar deduced drop size distribution function and that measured with the drop size distribution meter. Significant differences were noted and discussed. The drop size distribution measured at the surface by the disdrometer was graphically integrated and a theoretical ratio of the orthogonal components of the scattered field determined. This study was made for each drop size distribution obtained for different rain rates. The general slopes of the curves so obtained were found to be in good agreement with a curve determined for assumed Rayleigh scattering. Departures were noted and discussed on the basis of scattering theory. The measurements were found to be well within the limits predicted by scattering theory. (Author)