AbstractsPhysics

Because of the fluctuating nature of the radar echo from randomly distributed precipitation particles, several individual echo measurements have to be averaged to provide a meaningful estimate of intensity. Photography of a cathode ray tube inevitably provides some averaging by integration on film, over the area of the writing spot. Further areal integration has been achieved by rectangular scanning of fast-processed film at a rate of a few lines per second with a spot of diameter one-half mile. The effective area of integration by first writing and then reading the pattern is one square mile. The areally-averaged signals are subsequently stepped into seven levels, a factor 10 apart in received power, and displayed on a stepped grey scale on facaimile paper. This presentation is well suited for a visual quantitative estimate of echo intensity. [...]