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<br />rawinsondes launched at 3-hour <br />intervals, and a triple doppler <br />network. These instruments were <br />coordinated to obtain a maximum <br />comparison of information by all <br />instruments observing the same <br />portion of storms or scanning <br />larger segments of storms indepen- <br />dently. The King Air 200 was used <br />as the focal point of coordination. <br />When it was in range of ground <br />equipment, observations were <br />intensified along its track. Three <br />basic storm types were observed-- <br />stable orographic clouds, convective <br />bands, and convective cells. <br />Canned flight patterns were used <br />for flights in stable orographic <br />clouds with notification given to <br />the doppler network and mobile <br />cloud laboratory when the aircraft <br />was approaching their observation <br />areas. Real-time flight control <br />was provided from the SKYWATER <br />radar near Sheridan when convective <br />bands or cells were present. <br />Patterns were flown which penetrated <br />important regions of a band or <br />group of cells and could also be <br />observed by the doppler network. <br /> <br />These observations obtained informa- <br />tion on horizontal and vertical <br />wind fields; turbulence; and cloud <br />particle sizes, concentrations, and <br />distributions. <br /> <br />3.2 To measure the 3-D transport and diffu- <br />sive properties of the atmosphere in <br />and around Sierra storms. <br /> <br />The primary pieces of research <br />equipment utilized for this <br />objective were the King Air 200 <br />with an on board NCAR counter and <br />turbulence instrumentation, two <br />doppler radars with turbulence <br />spectra capability, a seeder aircraft <br />to release chaff and silver iodide, <br />a ground seeder to release silver <br />iodide and take pibals, and rawinsonde <br />launches. <br /> <br />The objectives of this series of <br />experiments was to release chaff . <br />and silver iodide at several locatlons <br />and altitudes under various stability <br />conditions in the foothills of the <br />Sierra Nevada and observe by four <br />separate techniques transport and <br />diffusion ahead of a storm. The <br />four separate techniques were: 1. <br />direct measurement of AgI distribu- <br />tions in space and time by aircraft, <br />2. direct measurement of chaff <br />distributions in space and time by <br />radar, 3. measurement of aircraft <br />turbulence and winds and calculation <br />of transport and diffusion, and 4. <br />measurement of velocity spectra <br />using chaff and radar and calculation <br />of transport and diffusion. Cases <br /> <br />163 <br /> <br />, ~ .- "t. <br /> <br />3.3 <br /> <br />were selected ahead of and behind <br />but not in the precipitation <br />region of storms. Overlying cloud <br />cover was required to prevent <br />surface heating and attendant <br />buoyant mixing. As the season <br />progressed and more experience was <br />gained in coordinating the various <br />pieces of equipment, releases of <br />silver iodide were made within <br />storms. Since chaff releases are <br />of little value in precipitation <br />and the direct measure of silver <br />iodide plumes in storm is so difficult, <br />only calculated estimates of trans- <br />port and diffusion from the aircraft <br />system remain in the storm. If the <br />aircraft turbulence system is <br />calibrated by the other three <br />systems in prestorm and poststorm <br />conditions, then data obtained by <br />the aircraft in all parts of storms <br />can be used to predict diffusion. <br />Information about winds and velocity <br />spectra in storms are also available <br />from the doppler radars. <br /> <br />To develop a climatology of several <br />important cloud properties which bear <br />on the potential for weather modifi- <br />cation. <br /> <br />The equipment used to develop a <br />climatology of Sierra storms was <br />the SKYWATER 5-cm radar and 3- <br />hourly rawinsondes launched near <br />Sheridan, California. The SKYWATER <br />radar was operated in two different <br />modes. One mode scanned at four <br />low elevation angles to obtain good <br />space-time resolution for convective <br />band and cell motions and for Z-R <br />calculations. A second mode scanned <br />from low elevation angles to very <br />high elevation angles. This scan <br />was used to characterize the cloud- <br />top distribution. The first mode <br />took 5 minutes to complete and the <br />second mode 15 minutes. During <br />normal operations mode 1 was repeated <br />3 times, mode 2 was completed, then <br />mode 1 was again repeated 3 times, <br />and so forth. Analysis of these <br />data are providing information on <br />where the clouds form, grow, and <br />dissipate and how they move relative <br />to upper level winds. In combination <br />with the rawinsonde data cloud <br />types, distributions, and sizes <br />will be determined and a climatology <br />developed. <br /> <br />3.4 <br /> <br />To evaluate the suitability of certain <br />instruments and techniques for con- <br />ductingand evaluating a randomized <br />cloud seeding experiment. <br /> <br />Several specific instruments were <br />evaluated for their suitability <br />during the randomized experiment. <br />Several types of precipitation <br />