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<br />a cloud where needed, and the problem of diffusion can be substantially <br />improved over that 'fac ing an airborne system. <br /> <br />An electro-mechanical system is used to inflate and launch the <br />balloons as well as to initialize the payload so it will activate when it <br />arrives at the proper altitude. The balloon sites are remotely located <br />and unattended. The spacing between sites and distance upwind from the <br />barrier are selected according to typical airflow speeds and diffusion <br />rates in clouds containing substantial .!mlounts of supercooled liquid <br />water. Selection of which sites to launch a balloon is made remotely. <br />The balloon housing is such that balloons exit through an 8' chimney; <br />precipitation entering the chimney falls directly beneath and does not <br />affect the balloon launching mechanisms. <br /> <br />Communications Systems Two specialized communication systems <br />have been developed for the weather modification research. However, <br />it is bel ieved that other appl ications of the system are possib Ie as <br />well. The basic concept is that both radio and telephone are used. <br />In particular, the balloon launches are made by sending certain telephone <br />tones over a telephone line to a transmitter located not very far fran <br />the balloon launching sites. These tones are relayed by the transmitter <br />to the sites, whereupon the messages are re~ceived and decoded. <br /> <br />A similar system has been develop,ed to send remotely located <br />radiometer data to abase station. In this case the order of signal <br />transmission is reversed; that 1S, the radio transmission goes to a <br />receiver co-located with a telephone at ~l pI ace where radio reception <br />is satisfactory. Signals are then sent over telephone lines to the <br />base station. Thus, both reception of radiometric or other data and <br />control of balloon launches can be accomplished at a single location <br />either near the project area or far removed. <br /> <br />t <br /> <br />Plans for Immediate Future Plans for the 1985-86 winter are <br />as follows: a Ka-band radar and a dual frequency microwave radiometer <br />will be operated continuously near the base of a mountain barrier. <br />Radiosondes and vibrating wire systems will be launched to obtain <br />standard parameters and the vertical distribution of LWC. Precipita- <br />tion, ice crystal replications, and ice crystal concentrations will be <br />measured at several locations during particular events. <br /> <br />"irhese events will be identified for substantial LWC and low pre- <br />cipitation rates; i.e., LWC/P is large. During such periods, sets of <br />balloons will be launched at two times. The time of first passage of <br />ice nuclei and any resulting precipitation will be predictable at the <br />various measuring sites on the basis of distance and airflow. The second <br />passage will be delayed after the first by the time separation between <br />the two sets of launches. Sudden changes in wind velocity are not <br />expected because an event will not be d,eclared when fronts or other <br />similar features are present. <br /> <br />The aim of this work is to obtain definite seeding signatures, <br />either by the radar or by the ground-based microphysical measurements. <br /> <br />47 <br />