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<br />experimental day following a seeded experimental day was contaminated by <br />nuclei returning from the west, after brea~~p of the blocking flow regime, <br />in 7.6 percent of the three-hour blocks. <br /> <br />5. Seeding appears to have affected a broad area lying up to 160 km <br />from the generator sites. Much of this effect occurred, as expected, down- <br />wind of the target area, with south to west winds. Some of the effect <br />occurred (unexpectedly) well to the west of the target area as a result of <br />seeding under blocking flow conditions. Over the downwind area (e.g., San <br />Luis Valley) any net increases in precipitation were small in absolute value. <br /> <br />6. The overall potential for precipitation enhancement by generators <br />located southwest of the San Juans was assessed at around ten percent, which <br />translates into an overall streamflow enhancement potential of around ~/" <br />percent. This potential was not fully realized in the seeded 24-hour experi- <br />mental days due to the following items: a) the opportunities lost 'with late <br />starts in the fall season, b) suspensions, c) missed forecasts of suitable <br />days, d) no increases in experimental day precipitation when strong blocking <br />flow deflected nucleant from the target area, e) increases in precipitation <br />on unseeded days actually seeded by nucleant from a preceding seeded day <br />with blocking flow, as explained in 4. above, f) losses when cold-top deep <br />but stable, orographic clouds were seeded when winds were strong, and g) <br />possible moderate seeding-produced losses on the upwind slopes when strong <br />convection was seeded. <br /> <br />7. Cases of snowfall days with suitable clouds, but with northerly <br />winds, were not studied as part of this experiment. Seeding with generators <br />located north and west of the target area could increase the potential evaluat- <br />ed in this report. <br /> <br />SUMMARY <br /> <br />Constraints imposed by randomization and by suspension permitted the <br />two primary goals of the project to be achieved with differing degrees of <br />success. Detailed a posteriori analysis demonstrated that wintertime preci- <br />pitation had been increased by seeding under certain cloud conditions and <br />decreased under others, agreeing with the findings of Climax. This confirmed <br /> <br />-19- <br />