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<br />Smith, P. L., L. R. Johnson, D. L. Priegnitz, and P. W. Mielke, Jr., 1992: A target-control analysis of wheat
<br />yield data for the North Dakota cloud modification project region. Journal of Weather Modification,
<br />24:98-105.
<br />
<br />A combined historical/target-control analysis of annual wheat yield data for western North Dakota
<br />provides indications of possible seeding effects in the target areas of the North Dakota Cloud
<br />Modification Project (NDCMP). The basic analysis procedure comproing post-1975 seeded-period data
<br />with pre-1961 non-seeded data gives an estimated yield increase of about 6%, relative to the control
<br />area, during the NDCMP operational period. However, the statistical (P-value) indieations of the
<br />significance of the difference are somewhat equivocal. The historical increase in yields due to
<br />improvements in agricultural technology apparently contributes to this difficulty, but an attempt to
<br />resolve the issue by redefining the historical reference period to reduce the time gap was unsuccessful.
<br />
<br />Smith. P. L., H. D. Orville, B. A. Boe, and J. L. Stith, 1992: A status report on weather modification research
<br />in the Dakotas. Atmospheric Research, 28:271-298.
<br />
<br />An overview of the status of weather modification research in North Dakota and South Dakota (USA) is
<br />presented. The operational North Dakota Cloud Modification Project has. since 1976, been seeding
<br />summer convective clouds for the dual objectives of hail suppression and rainfall enhancement.
<br />Research being carried out as part of a Federal/State cooperative program, in coordination with the
<br />operational activities, has included physical and statistical evaluation studies as well as numerical cloud
<br />modeling investigations. The statistical analyses provide some indications that the intended seeding
<br />effects are being obtained. The physical studies involve aircraft and radar observations and emphasize
<br />tracer experiments to study the transport and dispersion of seeding agents and the activation of ice
<br />nuclei. The modeling studies simulate the experiments and aid in investigation of the processes
<br />involved and the effects of seeding. The 1989 North Dakota Thunderstonn Project, a major field study
<br />emphasizing physical and numerical modeling studies, is described briefly.
<br />
<br />Smith, P. L., Z. Uu, and J. Joss., 1991: Apparent Z-R relationships arising from sampling variability in
<br />raindrop size observations. Preprints, 25th International Conference on Radar Meteorology, Paris,
<br />France. June 24-28. 1991. American Meteorological Society. Boston, MA, 760-763.
<br />
<br />No abstract.
<br />
<br />Smith. P. L., H. D. Orville, and B. A. Boe, 1991: An overview of the 1989 North Dakota Thunderstonn Project.
<br />Preprints, 2nd Yugoslav Conference on Weather Modification, Mavrovo, Yugoslavia, April 2-4, 1991.
<br />Republic Hydrometeorology Institute of SR, Macedonia. Skopje, Yugoslavia, 1:16-24.
<br />
<br />No abstract.
<br />
<br />Smith, P. L.. H. D. Orville, B. A. Boe, and J. L. Stith, 1991: Weather modification in the Dakotas. Preprints,
<br />2nd International Meeting on Agriculture and Weather Modification, Zamora, Spain, March 12-15, 1991.
<br />Ministry of Agriculture, Fisheries, and Nutrition, ISBN 84-87469-15-9..DL:LE-321-1991, Zamora, Spain,
<br />71-82.
<br />
<br />No abstract.
<br />
<br />71
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