Laserfiche WebLink
<br />Mesa Observatory near Montrose, Colorado, which began in 1983. These studie:s were focused <br />on optimizing the seeding technology by attaining: <br /> <br />a. More accurate climatology of winter cloud seeding opportunities. <br />b. More direct and accurate method to recognize seeding opportunities. <br />c. More consistent and precise means of treating clouds with seeding nuclei. <br /> <br />Preliminary analysis of these studies resulted in the following fmdings. It was observed that <br />SL W frequently occurred over the Mesa. The large number of hours with limited amounts <br />contributed to a significant SL W flux. The SL W often formed over the windward slopes, <br />persisted over the top, and rapidly evaporated to the lee of the barrier. Nature was inefficient <br />in converting the SL W into precipitation in many cases. <br /> <br />The SL W amounts were usually small compared to summertime convective clouds with a <br />vertically-integrated median value of 0.08 mm. Even when convection was present in the <br />winter clouds, fairly weak cells with limited vertical extent were generally produced. This <br />embedded convection infrequently yielded SL W values more than 0.4 mm. However, because <br />of the large number of hours with limited SLW, the seasonal water flux over the Mesa was <br />equivalent to a substantial fraction of the natural precipitation. This suggests that significant <br />potential may exist to augment the snowpack through cloud seeding. <br /> <br />Airflow studies revealed a complex pattern of wind perturbations around the Mesa. When <br />approaching the barrier, the low-level winds often decelerated on the upwind side and <br />accelerated downwind of the Mesa. Also, the winds usually deflected to cross the crest in a <br />nearly perpendicular direction. Southwesterly free airflow, which brought most of the SL W, <br />was diverted to southerly flow near the Mesa top. Similarly, northwest flow turned northerly <br />at low levels. This has important implications for targeting seeding material and resulting ice <br />particles. Besides diversions in transport directions, available growth times are reduced with <br />cross-axis flow. To successfully seed clouds over the Mesa it will be necessary to cause ice <br />nucleation sufficiently low and upwind for the resulting ice particles to reach the surface prior <br />to sublimating in the lee. <br /> <br />Southwest Cooperative Demonstration Program - lbe goal of this program was to test <br />existing cloud seeding technology for enhancing precipitation from summer convective clouds <br />and its feasibility as an alternative resource to augment the declining water supplies of west <br />Texas and Oklahoma as well as other semi-arid areas. An outgrowth of Reclamation's <br />Southwest Drought Research Program, the project was a cooperative effort between <br />Reclamation, the Texas Department of Water Resources and the Oldahoma Water Resources <br />Board. <br /> <br />The Texas field project was being conducted in conjunction with two locally funded <br />operational seeding projects. The focus was on increasing rainfall from small convective <br />clusters during the water critical periods of spring and early summer. <br /> <br />The Oklahoma project stressed development of rationales for applying the technology as well <br />as investigation of the economic, social, and environmental impacts of State-sponsored <br />operational seeding projects. <br /> <br />6 <br />