In the period from 13 Sept to 20 Sept 1979, the 430 MHz radar system at the Arecibo Observatory was used to study profiles of vertical velocity in developing and mature thunderstorms during the afternoon hours. During the eight day period, five days produced significant convective activity. The great sensitivity of the Arecibo radar facility al­lowed vertical velocities to be measured up to an altitude of 20 km. Since the tropopause over Puerto Rico is at an altitude of approximately 14 km at that time of year, the lower part of the stratosphere was also observed during the period of cloud development. Many studies have been carried out using Doppler radars to probe the interior of convective cells (see Wilson and Miller, 1972 for an excellent review and bibliography; also Battan, 1973). This is particularly true of radars operating at shorter wavelengths of 3 or 10 cm whích are more s...

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During the Condor campaign a number of instruments were set up in Peru to support the rocket experiments. In this series of papers we report on the results of the experiments designed to study the equatorial F region. In this overview paper we summarize the main results as well as report upon the macroscopic developments of spread F as evidenced by data from backscatter radars, from scintillation observations, and from digital ionosonde meaurements. In this latter regard, we argue here that at least two factors other than the classical gravitational Rayleigh-Taylor plasma instability process must operate to yield the longest-scale horizontal organization of spread F structures. The horizontal scale typical of plume separation distances can be explained by invoking the effect of a shear in the plasma flow, although detailed comparison with theory seems to require shear frequencies a bit h...