OCR Text |
Show Thus, even with the r ather small sample of just one operational season ' s d a t a, d · there is quite goo co mpar is on bet ween indicated Park Range seeding effects and those of the Climax project . 6. 2 Confirmation by Cloud Physic s Dat a Throughout the project, many snow crystal r eplic as and snow s amples were ii taken during each operational period. Contin uous ice nucleus c ounte rs were From the various analyses of these s p e cial :ar also operated in the target area. that: proven unequivocally is it data, support ~ 1 (1) silver concentration in target area precipitation was significantly .e~ (!) higher for seeded than for non-seeded periods. e~ the frequency of hexagonal plates (many of them very small) was wlii significantly higher for seeded than for non-seeded periods. Ti~ (3) some of the released Agl particles did serve as ice nuclei, to l! m crystals with Agl centers in the target area during seeding p eriods. snow mi• deposit (2) s), (4) many of the collected crystals possessing Agl centers were tiny .a ~:(< 100 µ) hexagonal plates, but there were also some Agl-centered dendrite s. ,i (5) Agl released from 20 to 50 km upwind of the target area (either rt· , by ground generators or aircraft) does frequently raise the surface air ice ;t 1 nuclei count strongly above natural background levels in the target area. iru~ r~ In addition, there is some, but not conclusive evidence that: ]ir: (1) riming rates decreased in response to seeding. seeding effects from a few minutes to an hour of seeding can con, tinue to affect silver concentrations in the target area precipitation for 3 to 4 hours, and in some cases for as long as 6 hours. (2) ,i~ (3) the frequency of dendrites decreases as the seeded he x agonal • • ci!~ P1ates mcrease m frequency. eri, 1 A~I 'fhe special support cloud physics data has proven extremely valua ble in the • ·1ar wea th e r mo ct·f· • any s1m1 1 i c aPark Range analysis scheme. Thus, m nol~ tion project, every effort should be made to obtain the m aximum a m ount of ·e!~ · this type of data. •!ii whole :ed1 6. 3 Use of Ground and Air Delivery Systems A lar ge number of diffusion tests w ere made i n which aircraft, instrumented 331 |