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Stanley A. Changnon

A new national effort dealing with planned and inadvertent weather modification has been recommended. The contention is that this readiness stems from finally learning important facts about how to properly design and conduct difficult experimentations; the need to study and understand ever growing inadvertent weather modification; the development of complex instrumentation and growing expertise; and more awareness of the impacts of changing the weather. Most importantly, awareness has come that progress can be made only through great attention to resolving many of the complex unknowns in the areas of cloud physics and dynamics. The potential benefits of an uncertain technology are difficult to specify, but appear sufficient to justify the research and development costs many have recommended. Either a better research program should be developed or we should essentially stop weather modification research.

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Donald Rottner, Stanley R. Brown, and Olin H. Foehner

of time and contaminate control experimental days when these control days immediately follow a seeded day. When the first 6 h periods of all such potentially contaminated days were placed in the seeded populationfor two randomized weather modification experiments, the Colorado River Basin Pilot Project (CRBPP)in the San Juan Mountains and the Jemez Atmospheric Water Resources Research Project (JAWRRP), astatistically significant seeding effect was detected. When the first 6 h periods were not

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David W. Reynolds, Thomas H. Vonder Haar, and Lewis O. Grant

During the past several years, many weather modification programs have been incorporating meteorological satellite data into both the operations and the analysis phase of these projects. This has occurred because of the advancement of the satellite as a mesoscale measurement platform, both temporally and spatially, and as the availability of high quality data has increased. This paper surveys the applications of meteorological satellite data to both summer and winter weather modification programs. A description of the types of observations needed by the programs is given, and an assessment of how accurately satellites can determine these necessary parameters is made.

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Rachel Hauser

, outcomes, the functions linking actions and outcomes, and any positive and negative payoffs associated with the potential activity ( Ostrom 1999 ; Folke et al. 2005 ; SRMGI 2011 ). At this time, a governance framework does not exist either for SRM specifically or for geoengineering in general. In considering what governance might be needed to carry forward a potential geoengineering development and deployment effort, weather modification governance may offer a useful proxy, as it is a technology

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Walter A. Lyons

JuLY 1974 W A L T E R A. L Y O N S 503Inadvertent Weather Modification by Chicago-Northern Indiana Pollution Sources Observed by ERTS-1~ WALTER m. LYONSAir Pollution A nalysis Laboratory, College of Engineering and Applied Science, University of Wisconsin-Milwaukee, Milwaukee, Wisc. 53201 (Manuscript received 2 November 1973, in

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Michael R. Poellot

A training program that has been conducted since 1974 to educate pilots in the principles of weather modification is described. The program offers theoretical and practical instruction in cloud seeding, including on-the-job experience. Some benefits of the program are presented.

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Stanley A. Changnon Jr.

A paradox has developed involving on one hand sizeable reductions during the last two years in federal support of weather modification, as opposed to major scientific-technical advances in the field plus strong recommendations for increased federal support from the scientific community. The major recent advances include the capability to operationally dissipate cold fogs, to enhance snow from orographic clouds, and to increase rain from tropical clouds, plus the discovery of sizeable urban-related increases in rainfall. Other advances include special weather radars, aircraft with new cloud sensors and the capability to penetrate thunderstorms, new seeding materials and delivery systems, and new techniques for evaluation of projects. These have been coupled with the spread of weather modification around the world and with the initiation of major seeding projects in Colorado (NHRE, HIPLEX, and San Juan Project), Florida, South Dakota, and Illinois-Missouri (METROMEX). Several groups (NACOA, NAS, ICAS, NWC, AMS) all made a series of positive recommendations for advancing the field through more federal support and reorganization. Yet, beginning in FY74, federal support for weather modification dropped 21% when other R&D increased 11%. Many possible causes for the paradox appear, including fear of weather changes, lack of scientific commitment, and a series of public, scientific, political, and military controversies. The three basic issues are that weather modification is still an immature technology; the socio-economic impacts are ill defined; and its management has been uncertain. Proper resolution of the paradox is more apt to occur either because of a dramatic scientific breakthrough or from growing concerns about weather and climate-related environmental changes.

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James A. Heimbach Jr. and Arlin B. Super

I176 JOURNAL OF APPLIED METEOROLOGY VOLU~t~ 19Raingage Network Requirements from a Simulated Convective Complex Weather Modification Experiment JAMES A. HEIMBACH, JR.tUniversity of North Dakota, Grand Forks, ND 58202 ARLIN B. SUPERWater and Power Resources Service, U,S. Department of the Interior, Miles City, MT 59701(Manuscript received 18 March 1980. in final form 14 July 1980

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Farn P. Parungo and J. Owen Rhea

468 JOURNAL OF APPLIED METEOROLOGY VOLUMg9Lead Measurement in Urban Air As It Relates to Weather Modification FA~N P. PARUNGO' AND J. OWEN RxiEAEG&G, Inc., Environmental Services Operation, Boulder, Colo.(Manuscript received 17 October 1969, in revised form 16 February 1970)Results from measurements rhode to study the behavior of lead aerosols in Denver urban air as latent icenuclei are discussed

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Roland List

The ever-increasing severe economic damage imposed on national and world wide economies by severe weather, the need for sufficient and safe water resources for an increasing world population, and the threat of adverse climate change led to this critical assessment of the state-of-the-art of weather modification (WM) and to a proposal of a road map for the future.

Special attention is given to rain enhancement because it is further developed than snowpack augmentation, hail suppression, tornado and hurricane modification, and other weather-related disaster control ideas. The question of what makes a rain enhancement experiment acceptable to the scientific community is answered by the World Meteorological Organization's (WMO) criteria, which address statistical evaluation, the measurement of rain, the understanding of nature's precipitation processes with the underlying physics and dynamics of clouds and cloud systems, and the transferability of experiment design. These criteria are no longer specific enough or satisfactory and will have to be reconsidered.

An actual WM experiment also involves a variety of techniques and technologies, aspects that need to be complemented by numerical modeling of clouds and cloud responses to seeding. Modeling also allows assessment of the extra-area effects, that is, detrimental effects of precipitation on adjacent areas. Assimilation models may be giving better estimates of the rain at the ground because they can integrate restricted information from radar and rain gauges with mesoscale meteorological and remote sensing, as well as hydrological, data. However, massive improvements in computer capacity are required to handle these problems.

Weather modification has been progressing very slowly in the past because of the enormity of the problem and the fact that the precipitation process is far from being understood. Considering that rain increases are attempted within a range of 10%–20%, the lack of knowledge at corresponding accuracy is particularly evident in the fields of cloud physics, cloud and cloud systems dynamics, weather forecasting, numerical modeling, and measuring technology.

Benefits of new intensive studies of precipitation processes will not be limited to WM; they are also vital to improving weather forecasting and climate change modeling. There is one additional aspect of WM; WM can also be used to test newly developed precipitation physics and models by studying if the clouds react to seeding in the predicted manner.

This article is a wake-up call to put more intellectual and financial resources into the exploration and modification of the precipitation processes in all their forms. All these points lead to the suggestion of an outline of a national precipitation research and weather modification program.

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