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<br />0025[10 <br /> <br />" <br /> <br />"In Nevada, the counties of Carson City, Douglas, Lyon, Storey, <br />and that part of Washoe south of 400 latitude; in California, <br />Plumas County south of 400 latitude and east of 1200 45' longi- <br />tude, Lassen County south of 400 latitude, Sierra and Nevada <br />Counties east of 1200 45' longitude, Alpine, Placer, and <br />El Dorado Counties east of the basin, and Mono County north <br />of 380 252 latitude. This region encompasses an area of <br />21,000 km. Based on the argument that the diffusional <br />characteristics of the seeding plume, as well as the trans- <br />port, tend to become linear with time at large distances from <br />the source, there is no reason to expect from a physical <br />point of view that downwind effects should not decrease in' <br />a linear manner. It is therefore recommended that the <br />density of downwind stations should decrease linearly from <br />the primary area across Region 2." <br /> <br />~ <br /> <br />, <br />N <br />i <br /> <br />The third region to be instrumented for precipitation is situated <br />below 1220 m (4000 ft) elevation and within the American River <br />Basin. The primary purpose of this system would be to provide real- <br />time precipitation data used as input for the declaration of an <br />experimental unit. The secondary benefit is to provide a better <br />definition of the precipitation distribution within the drainage <br />basin, especially as a function of altitude. Due to the real-time <br />requirement, the precipitation gage data should be telemetered. <br /> <br />Due to the mixed orographic-convective nature of Sierra Nevada <br />storms, MBA recommended that a 5-cm wavelength weather research <br />radar be used in conjunction with the seeding program. The radar <br />would aid in determination of cloud top heights and the location <br />of convective activity and would monitor storm conditions and <br />aircraft operational coordination. A cloud physics research <br />aircraft is also recommended until such time that a baseline of <br />cloud physics data relative to the varying conditions present in <br />Sierra Nevada storms has been established. <br /> <br />I <br />~ <br /> <br />Other standard data collection endemic to meteorological research <br />is also recommended, including upper air soundings and windfield <br />and moisture measurements at the surface. A dual doppler radar <br />system to resolve the three-dimensional wind structure of the storms <br />is also recommended, if possible, within the economic constraints of <br />the program. This type of system provides the most comprehensive <br />means available for resolution of air motion within the storm system. <br /> <br />t <br />f <br /> <br />Evaluation <br /> <br />MBA presented the following suggestions for evaluation of SCPP <br />operations: <br /> <br />25 <br />