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Dean E. Mann

In December 1955 a severe tropical storm caused severe flooding throughout Northern California with damage exceeding $200,000,000. One area suffering large-scale flooding was at Yuba City, at the confluence of the Feather and Yuba Rivers. The levees broke and consequent damage was in the magnitude of $65 million. Property-owners sought recompense through suits brought in the Superior Court of Sutter County against the State of California, Pacific Gas and Electric Company (PG&E), and North American Weather Consultants (NAWC).

PG&E, through its contracting agent, NAWC, had undertaken cloud seeding operations in three places in the high Sierras, one of which was in the Lake Almanor water-shed in the Feather River system. NAWC had interrupted seeding activities in that area three days before the levees broke at Yuba City. Plaintiffs charged that PG&E and NAWC were negligent in the operation of their generators, had contributed to the total quantity of water produced by the watershed and therefore were legally liable, and that cloud seeding was ultra-hazardous activity so that those engaged in such activities were strictly liable for damages.

The suit was begun in 1958 and concluded in 1964. Trial before a judge only began in October 1963 and a decision was rendered in April 1964. The judge ruled that neither PG&E nor NAWC was liable. In accordance with an agreement among the parties no appeal was taken. Plaintiffs were successful, however, against the State, basing their claim for damages on the doctrine of inverse condemnation which holds that the State must recompense for damages incurred in the lawful exercise of its powers—in this case, the construction of levees.

The litigation raises important questions of public policy with regard to weather modification and these are considered in the light of this case.

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Stanley A. Changnon

Large metropolitan areas in North America, home to 65% of the nation's population, have created major changes in their climates over the past 150 years. The rate and amount of the urban climate change approximate those being predicted globally using climate models. Knowledge of urban weather and climate modification holds lessons for the global climate change issue. First, adjustments to urban climate changes can provide guidance for adjusting to global change. A second lesson relates to the difficulty but underscores the necessity of providing scientifically credible proof of change within the noise of natural climatic variability. The evolution of understanding about how urban conditions influence weather reveals several unexpected outcomes, particularly relating to precipitation changes. These suggest that similar future surprises can be expected in a changed global climate, a third lesson. In-depth studies of how urban climate changes affected the hydrologic cycle, the regional economy, and human activities were difficult because of data problems, lack of impact methodology, and necessity for multidisciplinary investigations. Similar impact studies for global climate change will require diverse scientific talents and funding commitments adequate to measure the complexity of impacts and human adjustments. Understanding the processes whereby urban areas and other human activities have altered the atmosphere and changed clouds and precipitation regionally appears highly relevant to the global climate-change issue. Scientific and governmental policy development needs to recognize an old axiom that became evident in the studies of inadvertent urban and regional climate change and their behavioral implications: Think globally but act locally. Global climate change is an international issue, and the atmosphere must be treated globally. But the impacts and the will to act and adjust will occur regionally.

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R. I. Sax, S. A. Changnon, L. O. Grant, W. F. Hitschfeld, P. V. Hobbs, A. M. Kahan, and J. Simpson

, each of which might carry different ramifications toward the validity, applicability,and economic feasibility of weather modification procedures. However, as the ever-expanding world population becomes critically dependent upon bountiful food ~ An excellent up-to-date review of the subject can be found inthe book W~at~r and Climat~ Modification, edited b~r W. N. Hess,and published in 1974 by John Wile, and Sons.production in certain, relatively small, agriculturalregions of this planet, it is

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Meral Demirtas and Alan J. Thorpe

. The method presented in this paper can be used to improve short-range weather forecasts. In effect the PV and WV image-based approach serves to pinpoint the location and subsynoptic-scale structure of the upper-level features. In cases where the analysis errors occur in the upper troposphere the method can lead to a significant improvement in the short-range forecast skill. Upper/low-level PV modifications emphasize the importance of upper- and low-level data for NWP. Focusing on predictability

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R. Maine and D. J. Gauntlett

18 JOURNAl. OF APPLIED METEOROLOGY VOLUMe?Modifications to an Operational Numerical Weather Analysis System and Application to Rainfall R. MAINE ANn D. J. GAUlqTLETT Bureau of Meteorology, Mdbourne, Australia (Manuscript received 6 July 1967, in revised form 19 October 1967) ABSTRACT Modifications are made to an operational numerical weather

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F. A. Huff and S. A. Changnon Jr.

3?6 JOURNAL OF APPLIED METEOROLOGY VOLU~EllEvaluation of Potential Effects of Weather Modification on Agriculture in Illinois F. A. Htm~ AN~) S. A. CnANO~OS, J'~.Illinois Slat* Water $ur~y, Urbana 61801(Manuscript received 26 July 1971, in revised form 15 October 1971) An investigation was made of the potential effects of modifying growing-season rainfall on the yields

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Paul W. Mielke Jr., James S. Williams, and Sing-chou Wu

1977 P. W. M I E L K E, J. S. W I L L I A M S A N D S- C. W U 183Covariance Analysis Technique Based on Bivariate Log-NormalDistribution with Weather Modification Applications PAUL W. MIELKE, J~t., ANi) ]tml~S S. W~LZ~A~S Department of Statistics, Colorado State University, Fort Collins 80523 SXNG-C~OU WuDepartment of Computer Science and Statistics, California Polytechnic State University, San Luis

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N. Fukuta and Y. Paik

996 JOURNAL OF APPLIED METEOROLOGY VoLu~15A Supersonic Expansion Method of Ice Nuclei Generation for Weather Modification~ N. FvitrrA ~ -. P~u~~ Den~r Reze~h Insgt~e, University of D~, D~, Co~. 80210 (M~pt r~ved 18 Feb~ 1976) ~ST~CT Aeroso~ of Orphic ice nudging a~n~ were fo~ by rapid a~ba~c ~on, by p~g sup~h~t~ s~m l~en with the

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Lulin Xue, Sarah A. Tessendorf, Eric Nelson, Roy Rasmussen, Daniel Breed, Shaun Parkinson, Pat Holbrook, and Derek Blestrud

1. Introduction The National Research Council (2003) provided two recommendations on numerical modeling efforts related to intentional weather modification: 1) improving cloud model treatment of cloud and precipitation physics, and 2) improving and using current computational and data assimilation capabilities. During the last decade, rapid progress has been made in these two areas. For example, the Wyoming Weather Modification Pilot Program (WWMPP; Breed et al. 2011 ) applied a state

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Bart Geerts, Qun Miao, Yang Yang, Roy Rasmussen, and Daniel Breed

1. Introduction In a 2008 editorial column in Nature , it was argued that “… weather modification is one of those areas in which science can have an immediate and obvious benefit for society” ( Nature 2008 ). Cloud seeding probably has been the most widely practiced method of intentional weather modification for the last few decades (e.g., Bruintjes 1999 ; Qiu and Cressey 2008 ). It is remarkable that notwithstanding a series of targeted field campaigns and the stronger experimental control

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